Method and apparatus for determining whether r-wave detection should be classified as false

Abstract

Methods, devices, and systems for determining whether an R-wave detection should be classified as a false R-wave detection due to T-wave over sensing (TWO) or P-wave over sensing (PWO) are described herein. One such method includes comparing a particular morphology feature (e.g., peak amplitude) associated with the R-wave detection to a particular morphology feature associated with each of a first set of earlier detected R-wave detections to determine whether a first TWO or PWO morphology criterion is met, and comparing the particular morphology feature (e.g., peak amplitude) associated with the R-wave detection to a particular morphology feature associated with each of a second set of earlier detected R-wave detections to determine whether a second TWO or PWO morphology criterion is met, where the second set is different from the first set, but can have some overlap with the first set. The method further includes determining whether to classify the R-wave detection as a false R-wave detection based on whether one of the first TWO or PWO morphology criterion or the second TWO or PWO morphology criterion is met.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Nonprovisional Patent Application No. 17 / 723,207, filed April 18, 2022, and U.S. Provisional Patent Application No. 63 / 213,660, filed June 22, 2021, entitled “Methods and Systems for Determining Whether R-Wave Deceptions Should Be Classified as Failed Due to T-Wave Oversensing (TWO) or P-Wave Oversensing (PWO)”.

[0003] This application relates to U.S. Patent Application No. 17 / 153,036, filed January 20, 2021, entitled “METHODS AND SYSTEMS FOR DISTINGUISHING OVER-SENSED R-RINTERVALS FROM TRUE R-RINTERVALS”. Technical Field

[0004] The embodiments described herein relate to the analysis of electrogram (EGM) or electrocardiogram (ECG) signals, and more specifically, to determining whether R-wave detection should be classified as an error due to T-wave oversensing (TWO) or P-wave oversensing (PWO). Background Technology

[0005] Various types of implantable medical devices (IMDs) are used to monitor cardiac arrhythmias. Some types of IMDs, such as implantable pacemakers and implantable cardioverter defibrillators (ICDs), can provide appropriate treatment in response to detected arrhythmias.

[0006] Recent developments in nonvascular ICDs (NV-ICDs) (also known as subcutaneous ICDs (S-ICDs)) have simplified the implantation process for ICD patients. While traditional ICDs use bipolar intracardiac electrogram signals to detect rhythm, S-ICDs rely on far-field subcutaneous EGMs. These far-field EGMs, similar to surface ECGs, often include very large P and T waves, which can be falsely oversensed as R waves. This oversensing can ultimately lead to false detections of ventricular tachycardia (VT) or ventricular fibrillation (VF) and / or other types of arrhythmias, potentially resulting in inappropriate treatment delivery (e.g., shock). VT and VF can be detected by measuring the RR interval or its running average and comparing it to VT and VF detection thresholds. False positive VT and VF detections are highly undesirable because they can lead to inappropriate treatment delivery, such as shocks, which prematurely deplete the ICD's battery and cause patient distress.

[0007] Other types of IMDs (such as insertable cardiac monitors (ICMs)) are used for diagnostic purposes. ICMs are increasingly used to diagnose cardiac arrhythmias, including atrial fibrillation (AF). AF is a very common supraventricular tachycardia (SVT), causing approximately one in five strokes and is a major risk factor for ischemic stroke. However, AF is often asymptomatic and intermittent, which often leads to delays in appropriate diagnosis and / or treatment. To overcome this, many cardiac devices, such as ICMs, now monitor AF by acquiring an electrogram (EGM) signal and measuring RR interval variability based on the EGM signal. For example, an ICM or other IMD can compare a measurement of RR interval variability to a variability threshold to automatically detect AF when the threshold is exceeded. In fact, ICMs primarily identify AF by quantifying the variability of RR intervals (i.e., by quantifying the variability of ventricular systolic time). False positive AF detections are highly undesirable because the burden of sorting through a large number of clinically irrelevant AF episodes can be both time-consuming and costly.

[0008] Current P-wave and T-wave detection discriminator technologies are generally unable or insufficient to correctly distinguish between P-waves and T-waves and R-waves, often resulting in oversensitized P-waves and oversensitized T-waves, both of which are types of erroneous R-wave detection. Therefore, improved techniques are still needed to differentiate between P-waves and T-waves and R-waves, as well as to distinguish between oversensitized RR intervals and true RR intervals. In other words, improved methods, devices, and systems are still needed to distinguish between true R-wave detections and erroneous R-wave detections, and more generally, to detect T-wave oversensitization (TWO) and / or P-wave oversensitization (PWO). Summary of the Invention

[0009] Some embodiments of this technology relate to methods and apparatus for determining whether an R-wave detection should be classified as an erroneous R-wave detection due to TWO or PWO. According to some embodiments, a method includes: comparing a specific morphological feature (e.g., peak amplitude (A)) associated with an R-wave detection with a specific morphological feature associated with each R-wave detection in a first set of earlier detected R-wave detections to determine whether a first TWO or PWO morphological criterion is met; and comparing the specific morphological feature associated with an R-wave detection with a specific morphological feature associated with each R-wave detection in a second set of earlier detected R-wave detections to determine whether a second TWO or PWO morphological criterion is met, wherein the second set differs from the first set but may have some overlap with the first set. The method further includes: determining whether an R-wave detection is classified as an erroneous R-wave detection based on whether one of the first TWO or PWO morphological criteria or the second TWO or PWO morphological criteria is met. In some embodiments, the first set of earlier detected R-wave detections includes R-wave detections that were detected one, two, or three times earlier; and the second set of earlier detected R-wave detections includes R-wave detections that were detected two, three, or four times earlier. In some such embodiments, determining whether to classify an R-wave detection as an erroneous R-wave detection includes classifying the R-wave detection as an erroneous R-wave detection in response to meeting one of a first TWO or PWO morphological criterion or a second TWO or PWO morphological criterion.

[0010] According to some embodiments, a specific morphological feature includes a peak amplitude (A). In some such embodiments, a first TWO or PWO morphological criterion is satisfied when the peak amplitude A(n) associated with R-wave detection is at least a specified degree lower than the peak amplitude A(n-1) associated with an R-wave detection one R-wave earlier, at least not a specified degree lower than the peak amplitude A(n-2) associated with an R-wave detection two R-wave earlier, and at least a specified degree lower than the peak amplitude A(n-3) associated with an R-wave detection three R-wave earlier. In some such embodiments, a second TWO or PWO morphological criterion is satisfied when the peak amplitude A(n) associated with R-wave detection is at least a specified degree lower than the peak amplitude A(n-2) associated with an R-wave detection two R-wave earlier, at least not a specified degree lower than the peak amplitude A(n-3) associated with an R-wave detection three R-wave earlier, and at least a specified degree lower than the peak amplitude A(n-4) associated with an R-wave detection four R-wave earlier.

[0011] According to some embodiments, a specific morphological feature includes the area under the curve (AUC). In some such embodiments, a first TWO or PWO morphological criterion is satisfied when the AUC(n) associated with R-wave detection is at least a specified amount smaller than the AUC(n-1) associated with R-wave detection one R-wave earlier, at least not a specified amount smaller than the AUC(n-2) associated with R-wave detection two R-wave earlier, and at least a specified amount smaller than the AUC(n-3) associated with R-wave detection three R-wave earlier. In some such embodiments, a second TWO or PWO morphological criterion is satisfied when the AUC(n) associated with R-wave detection is at least a specified amount smaller than the AUC(n-2) associated with R-wave detection two R-wave earlier, at least not a specified amount smaller than the AUC(n-3) associated with R-wave detection three R-wave earlier, and at least a specified amount smaller than the AUC(n-4) associated with R-wave detection four R-wave earlier.

[0012] According to some embodiments, a specific morphological feature includes a width (W) associated with R-wave detection. In some such embodiments, a first TWO or PWO morphological criterion is satisfied when the width W(n) associated with R-wave detection is at least a specified amount longer than the width W(n-1) associated with an R-wave detection one R-wave earlier, at least not a specified amount longer than the width W(n-2) associated with an R-wave detection two R-wave earlier, and at least a specified amount longer than the width W(n-3) associated with an R-wave detection three R-wave earlier. In some such embodiments, a second TWO or PWO morphological criterion is satisfied when the width W(n) associated with R-wave detection is at least a specified amount longer than the width W(n-2) associated with an R-wave detection two R-wave earlier, at least not a specified amount longer than the width W(n-3) associated with an R-wave detection three R-wave earlier, and at least a specified amount longer than the width W(n-4) associated with an R-wave detection four R-wave earlier. Each width can be, for example, one of the following measurements associated with the corresponding R-wave detection: the full width at the threshold detection intersection, the full width at half maximum (FWHM), or the half width at half maximum (HWHM).

[0013] According to some embodiments, a specific morphological feature includes a maximum slope (MS) associated with R-wave detection. In some such embodiments, a first TWO or PWO morphological criterion is satisfied when the MS(n) associated with R-wave detection is at least a specified amount smaller than the MS(n-1) associated with an R-wave detection one R-wave earlier, at least not a specified amount smaller than the MS(n-2) associated with an R-wave detection two R-wave earlier, and at least a specified amount smaller than the MS(n-3) associated with an R-wave detection three R-wave earlier. In some such embodiments, a second TWO or PWO morphological criterion is satisfied when the MS(n) associated with R-wave detection is at least a specified amount smaller than the MS(n-2) associated with an R-wave detection two R-wave earlier, at least not a specified amount smaller than the MS(n-3) associated with an R-wave detection three R-wave earlier, and at least a specified amount smaller than the MS(n-4) associated with an R-wave detection four R-wave earlier.

[0014] According to some embodiments, determining whether to classify an R-wave detection as an erroneous R-wave detection includes classifying the R-wave detection as an erroneous R-wave detection in response to meeting one of a first TWO or PWO morphological criterion or a second TWO or PWO morphological criterion.

[0015] According to some embodiments, the method further includes: comparing the duration of the RR interval associated with an R-wave detection with the duration of the RR interval associated with each R-wave detection in a third group of earlier detected R-wave detections to determine whether a first TWO or PWO timing criterion is met; and comparing the duration of the RR interval associated with an R-wave detection with the duration of the RR interval associated with each R-wave detection in a fourth group of earlier detected R-wave detections to determine whether a second TWO or PWO timing criterion is met, wherein the fourth group differs from the third group but may have some overlap with the third group. In this method, it is also determined whether an R-wave detection is classified as an erroneous R-wave detection based on whether one of the first TWO or PWO timing criteria or the second TWO or PWO timing criteria is met. In some such embodiments, the third group of earlier detected R-wave detections includes R-wave detections that are one or two R-wave detections earlier; and the fourth group of earlier detected R-wave detections includes R-wave detections that are two or three R-wave detections earlier. In some such embodiments, a first TWO or PWO timing criterion is met when the RR interval duration D(n) associated with an R-wave detection is not similar to the RR interval duration D(n-1) associated with an R-wave detection that is one R-wave earlier, but is similar to the RR interval duration D(n-2) associated with an R-wave detection that is two R-wave earlier. A second TWO or PWO timing criterion is met when the RR interval duration D(n) associated with an R-wave detection is not similar to the RR interval duration D(n-2) associated with an R-wave detection that is two R-wave earlier, but is similar to the RR interval duration D(n-3) associated with an R-wave detection that is three R-wave earlier. In some such embodiments, determining whether to classify an R-wave detection as an erroneous R-wave detection includes classifying an R-wave detection as an erroneous R-wave detection in response to both the first TWO or PWO morphological criterion and the first TWO or PWO timing criterion; or both the second TWO or PWO morphological criterion and the second TWO or PWO timing criterion.

[0016] According to certain embodiments of the present technology, a device includes two or more electrodes, sensing circuitry, and a processor or controller. The sensing circuitry is coupled to the two or more electrodes and configured to acquire one or more ECG or EGM signals indicative of the electrical activity of a patient's heart. Using such a device (which may be an implantable medical device (IMD)), R-wave detection is performed based on comparing a sample of signals indicative of the patient's heart's electrical activity with an R-wave detection threshold. According to certain embodiments, to determine whether an R-wave detection should be classified as an erroneous R-wave detection due to TWO or PWO, the processor or controller is configured to compare specific morphological features associated with the R-wave detection with specific morphological features associated with each R-wave detection in a first set of earlier detected R-wave detections to determine whether a first TWO or PWO morphological criterion is met, and to compare specific morphological features associated with the R-wave detection with specific morphological features associated with each R-wave detection in a second set of earlier detected R-wave detections to determine whether a second TWO or PWO morphological criterion is met, wherein the second set differs from the first set but may have some overlap with the first set. In addition, the processor or controller is configured to determine whether to classify an R-wave detection as an erroneous R-wave detection based on whether one of the first TWO or PWO morphological criteria or the second TWO or PWO morphological criteria is met.

[0017] According to certain embodiments, the first group of earlier detected R-wave detections includes R-wave detections that are one, two, or three R-wave detections earlier; and the second group of earlier detected R-wave detections includes R-wave detections that are two, three, or four R-wave detections earlier. In some such embodiments, the processor or controller is configured to classify R-wave detections as erroneous R-wave detections in response to satisfying one of a first TWO or PWO morphological criterion or a second TWO or PWO morphological criterion.

[0018] According to some embodiments, a specific morphological feature includes a peak amplitude (A). In some such embodiments, the processor or controller is configured to determine that a first TWO or PWO morphological criterion is met when the peak amplitude A(n) associated with R-wave detection is at least lower than the peak amplitude A(n-1) associated with an R-wave detection one R-wave earlier, at least not lower than the peak amplitude A(n-2) associated with an R-wave detection two R-wave earlier, and at least lower than the peak amplitude A(n-3) associated with an R-wave detection three R-wave earlier. The processor or controller is configured to determine that the second TWO or PWO morphological criterion is satisfied when the peak amplitude A(n) associated with the R-wave detection is at least lower than the peak amplitude A(n-2) associated with the R-wave detection two R-wave detections earlier, at least not lower than the peak amplitude A(n-3) associated with the R-wave detection three R-wave detections earlier, and at least lower than the peak amplitude A(n-4) associated with the R-wave detection four R-wave detections earlier.

[0019] According to some embodiments, a specific morphological feature includes the area under the curve (AUC). In some such embodiments, the processor or controller is configured to determine that a first TWO or PWO morphological criterion is met when the AUC(n) associated with R-wave detection is at least a specified amount smaller than the AUC(n-1) associated with R-wave detection one R-wave earlier, at least not a specified amount smaller than the AUC(n-2) associated with R-wave detection two R-wave earlier, and at least a specified amount smaller than the AUC(n-3) associated with R-wave detection three R-wave earlier. The processor or controller is configured to determine that a second TWO or PWO morphological criterion is met when the AUC(n) associated with R-wave detection is at least a specified amount smaller than the AUC(n-2) associated with R-wave detection two R-wave earlier, at least not a specified amount smaller than the AUC(n-3) associated with R-wave detection three R-wave earlier, and at least a specified amount smaller than the AUC(n-4) associated with R-wave detection four R-wave earlier.

[0020] According to some embodiments, a specific morphological feature includes a width (W) associated with R-wave detection. In some such embodiments, a processor or controller is configured to determine that a first TWO or PWO morphological criterion is satisfied when the width W(n) associated with R-wave detection is at least as long as a specified amount longer than the width W(n-1) associated with an R-wave detection one R-wave earlier, at least not as long as a specified amount longer than the width W(n-2) associated with an R-wave detection two R-wave earlier, and at least as long as a specified amount longer than the width W(n-3) associated with an R-wave detection three R-wave earlier. The processor or controller is configured to determine that a second TWO or PWO morphological criterion is satisfied when the width W(n) associated with R-wave detection is at least as long as a specified amount longer than the width W(n-2) associated with an R-wave detection two R-wave earlier, at least not as long as a specified amount longer than the width W(n-3) associated with an R-wave detection three R-wave earlier, and at least as long as a specified amount longer than the width W(n-4) associated with an R-wave detection four R-wave earlier. Each width can be, for example, one of the following measurements associated with the corresponding R-wave detection: full width at the threshold detection intersection, FWHM, or HWHM.

[0021] According to some embodiments, a specific morphological feature includes a maximum slope (MS) associated with R-wave detection. In some such embodiments, the processor or controller is configured to determine that a first TWO or PWO morphological criterion is met when the MS(n) associated with R-wave detection is at least a specified amount smaller than the MS(n-1) associated with an R-wave detection one R-wave earlier, at least not a specified amount smaller than the MS(n-2) associated with an R-wave detection two R-wave earlier, and at least a specified amount smaller than the MS(n-3) associated with an R-wave detection three R-wave earlier. The processor or controller is configured to determine that a second TWO or PWO morphological criterion is met when the MS(n) associated with R-wave detection is at least a specified amount smaller than the MS(n-2) associated with an R-wave detection two R-wave earlier, at least not a specified amount smaller than the MS(n-3) associated with an R-wave detection three R-wave earlier, and at least a specified amount smaller than the MS(n-4) associated with an R-wave detection four R-wave earlier.

[0022] According to some embodiments, the controller or processor is configured to classify an R-wave detection as an erroneous R-wave detection in response to satisfying one of a first TWO or PWO morphological criterion or a second TWO or PWO morphological criterion.

[0023] According to some embodiments, the controller or processor is further configured to: compare the duration of the RR interval associated with an R-wave detection with the duration of the RR interval associated with each R-wave detection in a third group of earlier detected R-wave detections to determine whether a first TWO or PWO timing criterion is met; and compare the duration of the RR interval associated with an R-wave detection with the duration of the RR interval associated with each R-wave detection in a fourth group of earlier detected R-wave detections to determine whether a second TWO or PWO timing criterion is met, wherein the fourth group differs from the third group but may have some overlap with the third group. In some such embodiments, the controller or processor is configured to: further determine whether to classify an R-wave detection as an erroneous R-wave detection based on whether one of the first TWO or PWO timing criteria or the second TWO or PWO timing criteria is met.

[0024] According to some embodiments, a third group of earlier detected R-waves includes R-waves detected one or two times earlier; and a fourth group of earlier detected R-waves includes R-waves detected two or three times earlier. In some such embodiments, a processor or controller is configured to determine that a first TWO or PWO timing criterion is met when the RR interval duration D(n) associated with an R-wave detection is not similar to the RR interval duration D(n-1) associated with an R-wave detection one time earlier, but is similar to the RR interval duration D(n-2) associated with an R-wave detection two times earlier. A processor or controller is configured to determine that a second TWO or PWO timing criterion is met when the RR interval duration D(n) associated with an R-wave detection is not similar to the RR interval duration D(n-2) associated with an R-wave detection two times earlier, but is similar to the RR interval duration D(n-3) associated with an R-wave detection three times earlier.

[0025] According to some embodiments, the controller or processor is configured to classify an R-wave detection as an erroneous R-wave detection in response to either: meeting both a first TWO or PWO morphological criterion and a first TWO or PWO timing criterion; or meeting both a second TWO or PWO morphological criterion and a second TWO or PWO timing criterion.

[0026] According to some embodiments, the controller or processor is also configured to adjust at least one parameter of the R-wave detection threshold based on a determination of whether the R-wave detection should be classified as an erroneous R-wave detection due to TWO or PWO. For example, if at least a threshold number of R-wave detections in a specified number of R-wave detections (or within a specified time period) are classified as erroneous R-wave detections due to PWO, the R-wave detection threshold can be increased to reduce the chance of PWO. Alternatively, or additionally, if at least a threshold number of R-wave detections in a specified number of R-wave detections (or within a specified time period) are classified as erroneous R-wave detections due to TWO, the delayed decay of the R-wave detection threshold can be extended to reduce the chance of TWO, wherein the decay delay defines the period during which the amplitude or sensitivity level of the R-wave detection threshold remains constant after the refractory period expires and before the R-wave detection threshold begins to decrease in real time.

[0027] Some embodiments of this technology relate to a method for determining whether an R-wave detection should be classified as an erroneous R-wave detection due to TWO or P-wave oversensing PWO, the method comprising: obtaining a peak amplitude A(n) associated with the R-wave detection and corresponding peak amplitudes of other R-wave detections prior to the R-wave detection; determining whether the peak amplitude A(n) associated with the R-wave detection is at least lower than a peak amplitude A(n-1) associated with an R-wave detection one R-wave earlier, whether it is at least not lower than a peak amplitude A(n-2) associated with an R-wave detection two R-wave earlier, and whether it is at least higher than a peak amplitude A(n-3) associated with an R-wave detection three R-wave earlier. The criteria for determining whether a first TWO or PWO morphological standard is met are determined by determining whether the peak amplitude A(n) associated with an R-wave detection is at least lower than the peak amplitude A(n-2) associated with an R-wave detection that occurred two R-waves earlier, whether it is at least not lower than the peak amplitude A(n-3) associated with an R-wave detection that occurred three R-waves earlier, and whether it is at least lower than the peak amplitude A(n-4) associated with an R-wave detection that occurred four R-waves earlier; and in response to meeting either the first TWO or PWO morphological standard or the second TWO or PWO morphological standard, the R-wave detection is classified as an erroneous R-wave detection.

[0028] Some embodiments of this technology relate to a device including: two or more electrodes; sensing circuitry coupled to the two or more electrodes and configured to acquire signals indicative of electrical activity in a patient's heart; and a processor or controller. The processor or controller is configured to acquire a peak amplitude A(n) associated with an R-wave detection and corresponding peak amplitudes of other R-wave detections prior to the R-wave detection. The processor or controller is further configured to determine whether a first TWO or PWO morphological criterion is met by determining whether the peak amplitude A(n) associated with the R-wave detection is at least lower by a specified degree than the peak amplitude A(n-1) associated with an R-wave detection one R-wave earlier, whether it is at least not lower by a specified degree than the peak amplitude A(n-2) associated with an R-wave detection two R-wave earlier, and whether it is at least lower by a specified degree than the peak amplitude A(n-3) associated with an R-wave detection three R-wave earlier. The processor or controller is further configured to determine whether a second TWO or PWO morphological criterion is met by determining whether the peak amplitude A(n) associated with the R-wave detection is at least lower than a specified degree of the peak amplitude A(n-2) associated with an R-wave detection that occurred two R-waves earlier, whether it is at least not lower than a specified degree of the peak amplitude A(n-3) associated with an R-wave detection that occurred three R-waves earlier, and whether it is at least lower than a specified degree of the peak amplitude A(n-4) associated with an R-wave detection that occurred four R-waves earlier. The processor or controller is configured to classify the R-wave detection as an erroneous R-wave detection in response to meeting either the first TWO or PWO morphological criterion or the second TWO or PWO morphological criterion.

[0029] This overview is not intended to be a complete description of embodiments of the present technology. Other features and advantages of embodiments of the present technology will become apparent from the following description, taken in conjunction with the accompanying drawings and claims, in which preferred embodiments have been set forth in detail. Attached Figure Description

[0030] Figure 1 An example EMG signal is shown and used to explain how certain criteria (often referred to as the first TWO or PWO temporal criteria and the first TWO or PWO morphological criteria) can be used to determine whether an R-wave detection should be classified as an erroneous R-wave detection.

[0031] Figure 2 An example EMG signal is shown and used to explain how certain other criteria (often referred to as the second TWO or PWO temporal criteria and the second TWO or PWO morphological criteria) can be used to determine whether an R-wave detection should be classified as an erroneous R-wave detection.

[0032] Figure 3A and 3B(Collectively referred to as Figure 3) includes a high-level flowchart according to certain embodiments of the present technology describing a method for determining whether an R-wave detection should be classified as an erroneous R-wave detection due to TWO or PWO.

[0033] Figure 4A and Figure 4B (collectively referred to as Figure 4) provides some additional details on how to implement the method described with reference to Figure 3 according to certain embodiments of the present technology.

[0034] Figure 5 Includes advanced flowcharts describing how the first TWO or PWO timing criteria and the second TWO or PWO timing criteria can be used to determine whether an R-wave detection should be classified as an erroneous R-wave detection without using the first TWO or PWO morphological criteria and the second TWO or PWO morphological criteria.

[0035] Figure 6 Includes advanced flowcharts describing how the first TWO or PWO morphological standard and the second TWO or PWO morphological standard can be used to determine whether an R-wave detection should be classified as an erroneous R-wave detection without using the first TWO or PWO timing standard and the second TWO or PWO timing standard.

[0036] Figure 7 Includes another advanced flowchart describing how the first TWO or PWO morphological criteria and the second TWO or PWO morphological criteria can be used to determine whether an R-wave detection should be classified as an erroneous R-wave detection.

[0037] Figure 8 A block diagram of one embodiment of an IMD implanted in a patient according to certain embodiments of the present technology is shown. Detailed Implementation

[0038] As is well known, each cardiac cycle represented in the EGM or ECG typically includes a P wave, followed by a QRS complex, and then a T wave, where the QRS complex includes Q, R, and S waves. The P wave is caused by atrial depolarization. This is followed by atrial contraction, which indicates a slight increase in atrial pressure that contributes to further ventricular filling. After atrial contraction comes ventricular depolarization, as shown in the QRS complex, where ventricular depolarization initiates ventricular contraction, which causes a rise in ventricular pressure until it exceeds the diastolic pressure of the pulmonary and aorta, resulting in forward flow of blood as it exits the ventricles. Ventricular repolarization then occurs, as shown in the T wave, and this is associated with the onset of ventricular diastole, during which forward flow ceases, and the pressure in the ventricles drops below the pressure in the atria, at which point the mitral and tricuspid valves open to begin passively filling the ventricles during diastole. The terms EGM, EGM signal, and EGM waveform are used interchangeably throughout this document. Similarly, the terms ECG, ECG signal, and ECG waveform are used interchangeably in this document. Both ECG and EGM signals are signals that indicate the electrical activity of a patient's heart, and each can also be referred to as a signal indicating the electrical activity of the heart.

[0039] The R wave is the largest wave in the QRS complex and is typically identified by comparing a sample of the EGM or ECG to an R wave threshold, which is usually variable and generally depends on the peak amplitude of the detected R wave. Various measurements can be obtained based on the EGM or ECG waveform, including measurements of the RR interval, which is the duration between a pair of consecutive R waves. As mentioned above, in the background art, common techniques for detecting AF are based on measurements of RR interval variability, while common techniques for detecting VT and VF are based on measurements of RR interval duration or their running average. However, in cases where T waves and / or P waves are misidentified as R waves, highly variable erroneous RR intervals may be identified due to oversensitization, leading to false detections of AF. Oversensitized T waves and / or P waves can also lead to false detections of VT and VF. In other words, oversensitized P waves and / or oversensitized T waves can lead to false positive AF detections, false positive VT detections, and / or false positive VF detections. As used herein, an oversensitized P wave refers to a P wave that is misidentified as an R wave. Similarly, as used in this paper, an oversensitized T wave refers to a T wave that is incorrectly identified as an R wave. Therefore, it can be understood that an oversensitized T wave and an oversensitized P wave are examples of erroneous R wave detections caused by T wave oversensitization (TWO) and P wave oversensitization (PWO), respectively.

[0040] Some embodiments of this technology relate to methods and apparatus for determining whether P-wave and / or T-wave oversensing has occurred using the duration and peak amplitude of the RR interval (or other types of temporal and / or morphological features) associated with R-wave detection, and more generally, for distinguishing true R-wave detection from erroneous R-wave detection. Such embodiments can be advantageously used, for example, to prevent or reject erroneous positive VF detection, prevent or reject erroneous positive VT detection, and / or prevent or reject erroneous positive AF detection, but are not limited thereto. Therefore, it should be understood that such embodiments can be used to provide improved treatment delivery and / or improved use of clinical resources. For example, in the case of embodiments of this technology used to prevent or reject erroneous positive VF detection, this embodiment can be used to avoid the delivery of unnecessary defibrillation shocks that are painful to the patient and prematurely deplete the battery power from the IMD. For another example, in the case of embodiments of this technology used to prevent or reject erroneous positive VT detection, this embodiment can be used to avoid the delivery of unnecessary antitachycardia pacing (ATP), which can accelerate the sinus rhythm to VT or VF and prematurely deplete the battery power from the IMD. In yet another example, in the case of an embodiment of the present technology used to prevent or reject false positive detections of AF, this embodiment can be used to improve the use of clinical resources, where the clinician’s task is to analyze AF episodes detected and recorded by IMD.

[0041] As used in this document, a true RR interval refers to the actual RR interval, that is, the interval between two actual R waves. As used in this document, an incorrect RR interval refers to an interval that is incorrectly identified as an RR interval but is not an actual RR interval. Examples of interval types that may be incorrectly identified as RR intervals and therefore incorrect RR intervals include, but are not limited to, PR intervals, RT intervals, PT intervals, and TP intervals. A PR interval may be incorrectly identified as an RR interval where the P wave is oversensed. A RT interval may be incorrectly identified as an RR interval where the T wave is oversensed. A PT interval or TP interval may be incorrectly identified as an RR interval where the T and P waves are oversensed while the R wave is undersensed. These are merely a few examples of types of incorrect RR intervals and how they may occur, and are not intended to be exhaustive. An incorrect RR interval may also be referred to herein as an oversensed RR interval.

[0042] The RR interval is the duration between two consecutive R-wave detections; therefore, the RR interval may also be referred to as the RR duration in this document. More generally, it can be said that the RR interval duration associated with R-wave detections is the duration between the time of the R-wave detection and the time of the immediately preceding R-wave detection. When discussing R-wave detections, the immediately preceding R-wave detection may also be referred to as the R-wave detection of the earlier R-wave detection. The duration associated with an R-wave detection can be determined by the processor of the IMD, and other temporal and / or morphological features associated with the R-wave detection can also be determined. For example, the peak amplitude associated with an R-wave detection can be determined, for example, by determining the peak amplitude of the ECG or EGM signal within a window following the R-wave detection (e.g., a refractory period window, but not limited to this). Examples of other morphological features that can be determined for an R-wave detection include, but are not limited to, the maximum slope of the ECG or EGM signal within a specified window around or following the R-wave detection, the width associated with the R-wave detection, the morphological correlation of the ECG or EGM signal, the area under the curve (AUC) associated with the R-wave detection, the peak amplitude polarity of the R-wave detection, etc. For most of the remaining discussion, it is assumed that the morphological feature associated with the R-wave detection used to determine whether an R-wave detection should be classified as an erroneous R-wave detection is the peak amplitude associated with the R-wave detection. Furthermore, for most of the remaining discussion, it is assumed that the temporal feature associated with the R-wave detection used to determine whether an R-wave detection should be classified as an erroneous R-wave detection is the duration of the RR interval associated with the R-wave detection, where the associated RR interval duration is the duration (i.e., time length) between the R-wave detection and an earlier R-wave detection.

[0043] Some embodiments of the technology described herein rely on various criteria to identify erroneous R-wave detections. One criterion, which may be referred to as the first TWO or PWO timing criterion, is that the RR interval duration D(n) associated with an R-wave detection that is actually an oversensitized P-wave or T-wave should not be similar to the RR interval duration D(n-1) associated with an R-wave detection that is one R-wave detection earlier, and should be similar to the RR interval duration D(n-2) associated with an R-wave detection that is two R-wave detections earlier. As will be understood from the discussion below, the term "not similar" when used herein to describe how two RR interval durations are compared means that, regardless of calculation, the difference in durations exceeds a certain specified threshold. The term "similar" when used herein to describe how two RR interval durations are compared means that, regardless of calculation, the difference in durations is within a certain specified threshold. Two RR interval durations can also be said to be dissimilar if they are not similar to each other (because the difference in their durations exceeds the specified threshold).

[0044] Another criterion, which may be referred to as the first TWO or PWO morphological standard, is that the peak amplitude A(n) associated with an R-wave detection that is actually an oversensitized P-wave or T-wave should be lower than the peak amplitude A(n-1) associated with an R-wave detection that is one R-wave detection earlier, lower than the peak amplitude A(n-3) associated with an R-wave detection that is three R-wave detections earlier, but not lower than the peak amplitude A(n-2) associated with an R-wave detection that is two R-wave detections earlier. As will be understood from the discussion below, the term “lower than” when used herein to describe how two peak amplitudes are compared means that the value of one peak amplitude is at least a certain specified threshold smaller than the value of the other peak amplitude, or that the ratio of the values ​​of the two peak amplitudes is lower than a certain specific threshold. Note that the phrase “TWO or PWO” referring to T-wave oversensitization or P-wave oversensitization can be alternatively written as TWO / PWO.

[0045] According to some embodiments, if an R-wave detection satisfies both a first TWO or PWO timing criterion and a first TWO or PWO morphological criterion, the R-wave detection is classified as an erroneous R-wave detection, which may be caused by P-wave oversensing (PWO) or T-wave oversensing (TWO). Both the first TWO or PWO timing criterion and the first TWO or PWO morphological criterion can be satisfied; for example, in the case where the R-wave detection actually corresponds to a T-wave, an R-wave detection corresponding to one R-wave detection earlier is a true R-wave, an R-wave detection corresponding to two R-wave detections earlier is a T-wave, and an R-wave detection corresponding to three R-wave detections earlier is a true R-wave. An example of this situation is... Figure 1 As shown below, both the first TWO or PWO timing criterion and the first TWO or PWO morphological criterion can be satisfied. For example, in the case where the R-wave detection actually corresponds to the P-wave, the R-wave detection corresponding to one R-wave detection earlier is a true R-wave, the R-wave detection corresponding to two R-wave detections earlier is a P-wave, and the R-wave detection corresponding to three R-wave detections earlier is a true R-wave.

[0046] If the R-wave detection does not meet both the first TWO or PWO timing criterion and the first TWO or PWO morphological criterion, then according to certain embodiments of the present technology, if both the second TWO or PWO timing criterion and the second TWO or PWO morphological criterion are met, the R-wave detection can still be classified as an erroneous R-wave detection, as described below.

[0047] According to one embodiment, the second TWO or PWO timing criterion is that the duration of the RR interval D(n) associated with an R-wave detection that is actually an oversensitized P-wave or T-wave should be different from (i.e., not similar to) the duration of the RR interval D(n-2) associated with an R-wave detection that is two R-wave detections earlier, and should be similar to the duration of the RR interval D(n-3) associated with an R-wave detection that is three R-wave detections earlier. According to one embodiment, the second TWO or PWO morphological criterion is that the peak amplitude A(n) associated with an R-wave detection that is actually an oversensitized P-wave or T-wave should be lower than the peak amplitude A(n-2) associated with an R-wave detection that is two R-wave detections earlier, lower than the peak amplitude A(n-4) associated with an R-wave detection that is four R-wave detections earlier, but not lower than the peak amplitude A(n-3) associated with an R-wave detection that is three R-wave detections earlier. Both the second TWO or PWO timing criterion and the second TWO or PWO morphological criterion can be satisfied. For example, when an R-wave detection actually corresponds to a T-wave, an R-wave detection that is one R-wave earlier is a true R-wave, an R-wave detection that is two R-waves earlier is a true R-wave, an R-wave detection that is three R-waves earlier is a T-wave, and an R-wave detection that is four R-waves earlier is a true R-wave. An example of this situation is... Figure 2 As shown in the diagram, this will be discussed below. Alternatively, both the second TWO or PWO timing criterion and the second TWO or PWO morphological criterion can be satisfied. For example, in the case where the R-wave detection actually corresponds to the P-wave, the R-wave detection corresponding to one R-wave detection earlier is a true R-wave, the R-wave detection corresponding to two R-wave detections earlier is a true R-wave, the R-wave detection corresponding to three R-wave detections earlier is a P-wave, and the R-wave detection corresponding to four R-wave detections earlier is a true R-wave.

[0048] In summary, according to certain embodiments, if both the first TWO or PWO timing criterion and the first TWO or PWO morphological criterion are satisfied; or if both the second TWO or PWO timing criterion and the second TWO or PWO morphological criterion are satisfied, then the R-wave detection is classified as an erroneous R-wave. See below for further details. Figure 1 and Figure 2 These standards will be described in more detail.

[0049] Figure 1 An example EGM signal 101 sensed by an IMD (such as an S-ICD) is shown. The R-wave detection being analyzed is... Figure 1An R-wave detection, denoted as R(n), has an associated RR interval duration D(n) and an associated peak amplitude A(n). As described above, according to one embodiment, the first TWO or PWO timing criterion is that the RR interval duration D(n) associated with an R-wave detection that is actually an oversensitized P-wave or T-wave should be different from the RR interval duration D(n-1) associated with an R-wave detection that is one R-wave detection earlier, and should be similar to the RR interval duration D(n-2) associated with an R-wave detection that is two R-wave detections earlier. According to some embodiments, to determine whether D(n) is different from D(n-1), a percentage difference between D(n) and D(n-1) is determined, and the percentage difference between D(n) and D(n-1) is compared with a corresponding percentage threshold (e.g., 10%). Similarly, to determine whether D(n) is similar to D(n-2), the percentage difference between D(n) and D(n-2) is determined and compared to a corresponding percentage threshold (e.g., 10%). The percentage difference between D(n) and D(n-1) can be calculated using the following equation: % difference between D(n) and D(n-1) = 100 * |D(n) – D(n-1)| / D(n). Similarly, the percentage difference between D(n) and D(n-2) can be calculated using the following equation: % difference between D(n) and D(n-2) = 100 * |D(n) – D(n-2)| / D(n). From Figure 1 It can be seen that the percentage difference between D(n) and D(n-1) = 100 * |D(n) – D(n-1)| / D(n) = 100 * |0.30 - 0.45| / 0.3 = 50% > 10%. From... Figure 1 It can also be seen that the percentage difference between D(n) and D(n-2) = 100*|D(n)–D(n-2)| / D(n) = 100*|0.30-0.29| / 0.30 = 3.3% < 10%.

[0050] As described above, according to one embodiment, the first TWO or PWO morphological criterion is that the peak amplitude A(n) associated with an R-wave detection that is actually an oversensitized P-wave or T-wave should be lower than the peak amplitude A(n-1) associated with an R-wave detection that is one R-wave detection earlier, not lower than the peak amplitude A(n-2) associated with an R-wave detection that is two R-wave detections earlier, and lower than the peak amplitude A(n-3) associated with an R-wave detection that is three R-wave detections earlier. According to some embodiments, to determine whether A(n) is lower than A(n-1), a ratio of A(n) to A(n-1) is determined and compared to a corresponding ratio threshold (e.g., 0.4). Similarly, to determine whether A(n) is not lower than A(n-2), a ratio of A(n) to A(n-2) is determined and compared to a corresponding ratio threshold (e.g., 0.4). Furthermore, to determine whether A(n) is lower than A(n-3), the ratio of A(n) to A(n-3) is determined and compared with the corresponding ratio threshold (e.g., 0.4). The above ratios can be calculated using the following equations: Ratio of A(n) to A(n-1) = A(n) / A(n-1); Ratio of A(n) to A(n-2) = A(n) / A(n-2); and Ratio of A(n) to A(n-3) = A(n) / A(n-3). Figure 1 From this, we can understand that the ratio of A(n) to A(n-1) = A(n) / A(n-1) = 0.2 / 1.2 = 0.17 < 0.4. From... Figure 1 This can also be understood as the ratio of A(n) to A(n-2) = A(n) / A(n-2) = 0.2 / 0.2 = 1 > 0.4. Furthermore, from... Figure 1 It can be understood that the ratio of A(n) to A(n-3) = A(n) / A(n-3) = 0.2 / 1.2 = 0.17 < 0.4.

[0051] From reference Figure 1 As can be understood from the above example, in this example, both the first TWO or PWO timing criterion and the first TWO or PWO morphological criterion are satisfied. Therefore, in embodiments using this technology, the R-wave detection R(n) will be classified as an erroneous R-wave detection due to TWO or PWO.

[0052] As stated above, if an R-wave detection does not meet both the first TWO or PWO timing criterion and the first TWO or PWO morphological criterion, but meets both the second TWO or PWO timing criterion and the second TWO or PWO morphological criterion, the R-wave detection can still be classified as an erroneous R-wave detection. This is because if both the first TWO or PWO timing criterion and the first TWO or PWO morphological criterion are met, or if both the second TWO or PWO timing criterion and the second TWO or PWO morphological criterion are met, then the R-wave detection is classified as an erroneous R-wave.

[0053] Figure 2 An example EGM signal 201 sensed by an IMD (such as an S-ICD) is shown. The R-wave detection being analyzed is... Figure 2 An R-wave detection, denoted as R(n), has an associated RR interval duration D(n) and an associated peak amplitude A(n). As described above, according to one embodiment, the second TWO or PWO timing criterion is that the RR interval duration D(n) associated with an R-wave detection that is actually an oversensitized P-wave or T-wave should be different from the RR interval duration D(n-2) associated with an R-wave detection that is two R-wave detections earlier, and should be similar to the RR interval duration D(n-3) associated with an R-wave detection that is three R-wave detections earlier. According to some embodiments, to determine whether D(n) is different from D(n-2), a percentage difference between D(n) and D(n-2) is determined, and the percentage difference between D(n) and D(n-2) is compared with a corresponding percentage threshold (e.g., 10%). Similarly, to determine whether D(n) is similar to D(n-3), the percentage difference between D(n) and D(n-3) is determined and compared to a corresponding percentage threshold (e.g., 10%). The percentage difference between D(n) and D(n-2) can be calculated using the following equation: % difference between D(n) and D(n-2) = 100 * |D(n) – D(n-2)| / D(n). Similarly, the percentage difference between D(n) and D(n-3) can be calculated using the following equation: % difference between D(n) and D(n-3) = 100 * |D(n) – D(n-3)| / D(n). Figure 2 It can be seen that the percentage difference between D(n) and D(n-2) = 100*|D(n) – D(n-2)| / D(n) = 100*|0.3 - 0.6| / 0.3 = 100% > 10%. From... Figure 2 It can also be seen that the percentage difference between D(n) and D(n-3) = 100*|D(n)–D(n-2)| / D(n) = 100*|0.3-0.29| / 0.3 = 3.3% < 10%.

[0054] As described above, according to one embodiment, the second TWO or PWO morphological criterion is that the peak amplitude A(n) associated with an R-wave detection that is actually an oversensitized P-wave or T-wave should be lower than the peak amplitude A(n-2) associated with an R-wave detection that is two R-waves earlier, not lower than the peak amplitude A(n-3) associated with an R-wave detection that is three R-waves earlier, and lower than the peak amplitude A(n-4) associated with an R-wave detection that is four R-waves earlier. According to some embodiments, to determine whether A(n) is lower than A(n-2), a ratio of A(n) to A(n-2) is determined, and this ratio is compared to a corresponding ratio threshold (e.g., 0.4). Similarly, to determine whether A(n) is not lower than A(n-3), a ratio of A(n) to A(n-3) is determined, and this ratio is compared to a corresponding ratio threshold (e.g., 0.4). Furthermore, to determine whether A(n) is lower than A(n-4), the ratio of A(n) to A(n-4) is determined and compared with the corresponding ratio threshold (e.g., 0.4). The above ratios can be calculated using the following equations: the ratio of A(n) to A(n-2) = A(n) / A(n-2); the ratio of A(n) to A(n-3) = A(n) / A(n-3); and the ratio of A(n) to A(n-4) = A(n) / A(n-4). Figure 2 From this, we can understand that the ratio of A(n) to A(n-2) = A(n) / A(n-2) = 0.2 / 1.1 = 0.18 < 0.4. From... Figure 2 This can also be understood. The ratio of A(n) to A(n-3) = A(n) / A(n-3) = 0.2 / 0.15 = 1.3 > 0.4. Furthermore, from... Figure 2 It can be understood that the ratio of A(n) to A(n-4) = A(n) / A(n-4) = 0.2 / 1.2 = 0.17 < 0.4.

[0055] From reference Figure 2 As can be understood from the above example, in this example, both the second TWO or PWO timing criterion and the second TWO or PWO morphological criterion are satisfied. Therefore, in embodiments using this technology, the R-wave detection R(n) will be classified as an erroneous R-wave detection.

[0056] In alternative embodiments, instead of using percentage differences to compare the durations of RR intervals associated with various R-wave detections, a ratio can be used when determining whether a first TWO or PWO timing criterion or a second TWO or PWO timing criterion is met. For example, to determine whether the duration of D(n) differs from that of D(n-1), D(n) can be determined to be D(n) / D(n-1), which can be compared to a threshold. For example, if the ratio D(n) / D(n-1) is in the range of 0.9 to 1.1, the durations are considered similar, and if the ratio D(n) / D(n-1) is outside this range, the durations are considered dissimilar. Other ways of determining whether durations are similar or dissimilar are also possible and are within the scope of the embodiments described herein. Other thresholds may be used alternatively in addition to the example thresholds described herein.

[0057] In alternative embodiments, when determining whether a first TWO or PWO morphological criterion or a second TWO or PWO morphological criterion is met, instead of using ratios to compare amplitudes associated with various R-wave detections, percentage differences can be used. For example, to determine whether A(n) is lower than A(n-2) and by how much A(n) is lower than A(n-2), the percentage difference between A(n) and A(n-2) can be determined as 100*(A(n)-A(n-2)) / D(n), which can be compared to, for example, a threshold of -60%. Other ways of determining whether one peak amplitude is lower than another peak amplitude are also possible and are within the scope of the embodiments described herein. It is also noted that, in addition to (or excluding) peak amplitudes, one or more other types of morphological features associated with R-wave detection can be compared with each other to determine whether an R-wave detection should be classified as an erroneous R-wave detection. As described above, examples of other morphological features that can be used to determine R-wave detection (and to determine whether an R-wave detection should be classified as an erroneous R-wave detection) include, but are not limited to, the maximum slope (MS) within a window around or after the R-wave detection, the width (W) associated with the R-wave detection, the morphological correlation of the ECG or EGM signal, the area under the curve (AUC) associated with the R-wave detection, and the peak amplitude polarity of the R-wave detection. The maximum slope can be determined by determining the maximum derivative (dV / dt) of the ECG or EGM signal within a window around or after the R-wave detection. Such a window could be, for example, from 50 milliseconds (msec) before the R-wave detection to 50 milliseconds after the R-wave detection. Since the maximum slope of the P-wave or T-wave is typically lower than that of the true R-wave, similarly, the peak amplitude of the P-wave or T-wave is typically lower than that of the true R-wave, this morphological feature can be used to distinguish oversensitized P-waves or T-waves from true R-waves. Similarly, the area under the curve of the P-wave or T-wave between zero crossings is typically smaller than that of the true R-wave between zero crossings. Conversely, the width of a P wave or T wave is typically greater than the width of a true R wave. Therefore, if this morphological feature is used in a comparison, the logic used in the comparison should be modified accordingly, as understood by one of ordinary skill in the art upon reading this disclosure.

[0058] For the remainder of the discussion, unless otherwise stated, it is assumed that the morphological feature associated with the R-wave detection used to determine whether an R-wave detection should be classified as an erroneous R-wave detection is the peak amplitude associated with the R-wave detection. Additionally, for the remainder of the discussion, unless otherwise stated, it is assumed that the temporal feature associated with the R-wave detection used to determine whether an R-wave detection should be classified as an erroneous R-wave detection is the duration of the RR interval associated with the R-wave detection, where the associated RR interval duration is the duration (i.e., time length) between the R-wave detection and an earlier R-wave detection.

[0059] Figure 3A and 3B (Collectively referred to as Figure 3) includes a high-level flowchart describing a method for determining whether an R-wave detection is classified as an erroneous R-wave detection according to certain embodiments of the present technology.

[0060] refer to Figure 3A Step 302 involves obtaining an associated RR interval duration D(n) and an associated peak amplitude A(n) for R-wave detection. In one embodiment, the associated RR interval duration D(n) is the duration between an R-wave detection and an earlier R-wave detection. In one embodiment, the associated peak amplitude A(n) is the peak amplitude of the ECG or EGM signal within a window (e.g., a refractory period window, but not limited thereto) following the R-wave detection. For R-wave detection, the associated RR interval duration D(n) and associated peak amplitude A(n) can be determined by the processor of the IMD and can be stored in the memory of the IMD (e.g., a buffer memory) such that they can be used in the methods described herein and / or other methods. Similarly, corresponding RR interval durations and peak amplitudes can be determined and stored in memory for earlier (and later) R-wave detections such that such durations and peak amplitudes can be used in the methods described herein and / or other methods.

[0061] Still referencing Figure 3A Step 312 involves determining whether the RR interval duration D(n) associated with the R-wave detection is similar to or not similar to the RR interval duration D(n-1) associated with an R-wave detection that occurred one R-wave earlier, and whether it is similar to or not similar to the RR interval duration D(n-2) associated with an R-wave detection that occurred two R-wave earlier. Step 322 involves determining whether the RR interval duration D(n) associated with the R-wave detection is not similar to the RR interval duration D(n-1) associated with an R-wave detection that occurred one R-wave earlier, and whether it is similar to the RR interval duration D(n-2) associated with an R-wave detection that occurred two R-wave earlier. If the answer to the determination in step 322 is "yes," this means that the first TWO or PWO timing criterion is met, and the process proceeds to steps 322 and 342 to determine whether the first TWO or PWO morphological criterion is met. If the answer to the determination in step 322 is "no," this means that the first TWO or PWO timing criterion is not met, and the process proceeds to... Figure 3B Steps 362 and 372 are used to determine whether the second TWO or PWO timing criterion and the second TWO or PWO morphological criterion are met. Note that although steps 312 and 322 are shown as two steps, these two steps can be combined into a single step. It should also be noted that these steps can consist of multiple sub-steps, as discussed below. Figure 4A Understanding.

[0062] Still referencing Figure 3A Steps 332 and 342 involve determining whether the peak amplitude A(n) associated with the R-wave detection is at least lower than a specified degree of the peak amplitude A(n-1) associated with an R-wave detection one R-wave earlier, at least lower than a specified degree of the peak amplitude A(n-3) associated with an R-wave detection three R-wave earlier, and at least not lower than a specified degree of the peak amplitude A(n-2) associated with an R-wave detection two R-wave earlier. If the answer to step 342 is "yes," then the first TWO or PWO morphological criterion is satisfied, and the process proceeds to step 352, and the R-wave detection is classified as an erroneous R-wave detection caused by TWO or PWO. If the answer to step 342 is "no," then this means that the first TWO or PWO morphological criterion is not satisfied, and the process proceeds to... Figure 3B Steps 362 and 372 are used to determine whether the second TWO or PWO timing criterion and the second TWO or PWO morphological criterion are met. Note that although steps 332 and 342 are shown as two steps, these two steps can be combined into a single step. It should also be noted that these steps can consist of multiple sub-steps, as discussed below. Figure 4A Understanding.

[0063] Now for reference Figure 3B Step 362 involves determining whether the RR interval duration D(n) associated with the R-wave detection is similar to or not similar to the RR interval duration D(n-2) associated with an R-wave detection that is two R-waves earlier, and whether it is similar to or not similar to the RR interval duration D(n-3) associated with an R-wave detection that is three R-waves earlier. Step 372 involves determining whether the RR interval duration D(n) associated with the R-wave detection is not similar to the RR interval duration D(n-2) associated with an R-wave detection that is two R-waves earlier, and whether it is similar to the RR interval duration D(n-3) associated with an R-wave detection that is three R-waves earlier. If the answer to the determination in step 372 is "yes", then it is determined that the second TWO or PWO timing criterion is met, and the process proceeds to steps 382 and 392 to determine whether the second TWO or PWO morphological criterion is met. Note that although steps 362 and 372 are shown as two steps, these two steps can be combined into a single step. It should also be noted that these steps can consist of multiple sub-steps, as will be discussed below. Figure 4B The understanding is as follows. If the answer to step 372 is "no", it means that the second TWO or PWO time criterion is not met, and the process proceeds to step 394, in which the R-wave detection is not classified as an erroneous R-wave detection.

[0064] Still referencing Figure 3B Steps 382 and 392 involve determining whether the peak amplitude A(n) associated with the R-wave detection is at least lower than a specified degree of the peak amplitude A(n-2) associated with an R-wave detection two R-wave detections earlier, at least lower than a specified degree of the peak amplitude A(n-4) associated with an R-wave detection four R-wave detections earlier, and at least not lower than a specified degree of the peak amplitude A(n-3) associated with an R-wave detection three R-wave detections earlier. If the answer to the determination in step 392 is "yes," this means that the second TWO or PWO morphological criterion is met, and the process proceeds to step 352 (in Figure 3A (In the middle), and the R-wave detection is classified as an erroneous R-wave detection caused by oversensing of the P-wave or T-wave. If the definitive answer to step 392 is "no," it means that the second TWO or PWO morphological criterion is not met, and the process proceeds to step 394, in which the R-wave detection is not classified as an erroneous R-wave detection. Note that although steps 382 and 392 are shown as two steps, these two steps can be combined into a single step. It should also be noted that these steps can consist of multiple sub-steps, which will be discussed below. Figure 4B This is for your understanding. Furthermore, it should be noted that steps 382 and 392 may be performed before steps 362 and 372, or more generally, the determination of whether the second TWO or PWO morphological standard is met may be performed before determining whether the second TWO or PWO temporal standard is met.

[0065] Currently in use Figure 4A and 4B (collectively referred to as FIG4) illustrates how certain embodiments of the present technology may be implemented with reference to FIG3 (including FIG3). Figure 3A and 3B Some additional details about the method described.

[0066] refer to Figure 4A Step 302 is the same as the above reference. Figure 3AThe steps described in step 302 are the same, so there is no need to describe them again. Steps 404, 406, 408, and 410 can be used to perform the above steps 312 and 322, and more generally, can be used to determine whether the first TWO or PWO temporal criteria are met. Step 404 involves determining %Diff_1 = 100 * |D(n) – D(n-1)| / D(n). Step 406 involves determining %Diff_2 = 100 * |D(n) – D(n-2)| / D(n). Step 408 involves determining whether %Diff_1 (i.e., 100 * |D(n) – D(n-1)| / D(n)) is greater than a specified percentage difference threshold, such as 10%. Step 410 involves determining whether %Diff_2 (i.e., 100 * |D(n) – D(n-2)| / D(n)) is less than a specified percentage difference threshold, such as 10%. If the answers to the determinations in steps 408 and 410 are both "yes", this means that the first TWO or PWO temporal criteria are met, and then the process proceeds to steps 412 to 422 to determine whether the first TWO or PWO morphological criteria are met. If the answer to at least one of the determinations in steps 408 and 410 is "no", this means that the first TWO or PWO temporal criteria are not met, and the process proceeds to 424-430( Figure 4B in) to determine whether the second TWO or PWO temporal criteria are met.

[0067] Steps 412 to 422 can be used to perform the above steps 332 and 342, and more generally, can be used to determine whether the first TWO or PWO morphological criteria are met. Step 412 involves determining Ratio_1 = A(n) / A(n-1). Step 414 involves determining Ratio_2 = A(n) / A(n-2). Step 416 involves determining Ratio_3 = A(n) / A(n-3). Step 418 involves determining whether Ratio_1 < ratio threshold (R_TH) (e.g., 0.4). Step 420 involves determining whether Ratio_2 > R_TH (e.g., 0.4). Step 422 involves determining whether Ratio_3 < R_TH (e.g., 0.4). If the answers to the determinations in steps 418, 420, and 422 are all "yes", this means that the first TWO or PWO morphological criteria are met, and then the process proceeds to step 352. In step 352, the R-wave detection is classified as an erroneous R-wave detection caused by over-sensing of the P-wave or T-wave. If the answer to at least one of the determinations in steps 418, 420, and 422 is "no", this means that the first TWO or PWO morphological criteria are not met, and the process proceeds to steps 424 to 430( Figure 4B in) to determine whether the second TWO or PWO temporal criteria are met.

[0068] Now refer to Figure 4B, Steps 424, 426, 428, and 430 can be used to perform the above-mentioned steps 362 and 372, and more generally, can be used to determine whether the second TWO or PWO temporal criteria are met. Step 424 involves determining %Diff_2 = 100 * |D(n) – D(n - 2)| / D(n), which may have been determined in step 406, so if %Diff_2 is saved, it does not need to be determined again. Step 426 involves determining %Diff_3 = 100 * |D(n) – D(n - 3)| / D(n). Step 428 involves determining whether %Diff_2 > %TH (e.g., 10%). Step 430 involves determining whether %Diff_3 < %TH (e.g., 10%). If the answers to the determinations in steps 428 and 430 are both "yes", this means that the second TWO or PWO temporal criteria are met, and then the process proceeds to steps 432 to 442 to determine whether the second TWO or PWO morphological criteria are met. If the answer to at least one of the determinations in steps 428 and 430 is "no", this means that the second TWO or PWO temporal criteria are not met, and the process proceeds to step 394, where the R-wave detection is not classified as an incorrect R-wave detection.

[0069] Still referring to Figure 4B , Steps 432 to 442 can be used to perform the above-mentioned steps 382 and 392, and more generally, can be used to determine whether the second TWO or PWO morphological criteria are met. Step 432 involves determining Ratio_2 = A(n) / A(n - 2), which may have been determined in step 414, so if Ratio_2 is saved, it does not need to be determined again. Step 434 involves determining Ratio_3 = A(n) / A(n - 3), which may have been determined in step 416, so if Ratio_3 is saved, it does not need to be determined again. Step 436 involves determining Ratio_4 = A(n) / A(n - 4). Step 438 involves determining whether Ratio_2 < R_TH (e.g., 0.4). Step 440 involves determining whether Ratio_3 > R_TH (e.g., 0.4). Step 422 involves determining whether Ratio_4 < R_TH (e.g., 0.4). If the answers to the determinations in steps 438, 440, and 442 are all "yes", this means that the second TWO or PWO morphological criteria are met, and then the process proceeds to step 352 ( Figure 4A in). In step 352, the R-wave detection is classified as an incorrect R-wave detection caused by over-sensing of P waves or T waves. If the answer to at least one of the determinations in steps 438, 440, and 442 is "no", this means that the second TWO or PWO morphological criteria are not met, and the process proceeds to step 394, where the R-wave detection is not classified as an incorrect R-wave detection.

[0070] In the embodiments described above with reference to Figures 3 and 4, an R-wave detection is classified as an erroneous R-wave detection (caused by P-wave or T-wave oversensitivity) if both the first TWO or PWO timing criterion and the first TWO or PWO morphological criterion are met, or if both the second TWO or PWO timing criterion and the second TWO or PWO morphological criterion are met. To determine whether the first TWO or PWO timing criterion or the second TWO or PWO timing criterion is met, the RR interval duration associated with the R-wave detection is compared with each other. The RR interval duration is an example of a timing characteristic of the R-wave detection. To determine whether the first TWO or PWO morphological criterion or the second TWO or PWO morphological criterion is met, the peak amplitude associated with the R-wave detection is compared with each other. The peak amplitude is an example of a morphological characteristic associated with the R-wave detection. As described above, and explained in more detail below, in alternative embodiments, other types of morphological characteristics associated with the R-wave detection (instead of (or excluding) peak amplitude) may be compared with each other to determine whether the R-wave detection should be classified as an erroneous R-wave detection (caused by PWO or TWO).

[0071] In some embodiments with lower computational intensity but potentially lower positive predictive values, the temporal characteristics of R-wave detections can be compared with each other without comparing their morphological characteristics to determine whether an R-wave detection should be classified as an erroneous R-wave detection (caused by P-wave or T-wave oversensing). For a more specific example, according to some embodiments, the durations of the RR intervals associated with R-wave detections are compared with each other to determine whether one of a first TWO or PWO temporal criterion or a second TWO or PWO temporal criterion is met, and if so, the R-wave detection is classified as an erroneous R-wave detection (caused by PWO or TWO). Figure 5 An example high-level flowchart of this embodiment is shown. (Reference) Figure 5 Step 502 involves obtaining the associated RR interval duration D(n) for the R-wave detection. Steps 312 and 322 are used to determine whether a first TWO or PWO timing criterion is met. If the first TWO or PWO timing criterion is met, the answer to the determination in step 322 will be "yes," and in step 352, the R-wave detection will be classified as an erroneous R-wave detection. If the first TWO or PWO timing criterion is not met, steps 362 and 372 are used to determine whether a second TWO or PWO timing criterion is met. If the second TWO or PWO timing criterion is met, the answer to the determination in step 372 will be "yes," and in step 352, the R-wave detection will be classified as an erroneous R-wave detection. If neither the first TWO or PWO timing criterion nor the second TWO or PWO timing criterion is met, then in step 394, the R-wave detection will not be classified as an erroneous R-wave detection. Figure 5Steps 312, 322, 352, 362, 372, and 394 shown have already been described above with reference to Figure 3, and therefore do not need to be described again. Figure 4 above describes some additional example details of how to perform these steps.

[0072] In some other embodiments with lower computational intensity but similarly likely lower positive predictive values, the morphological characteristics of R-wave detections can be compared with each other without comparing the temporal characteristics of R-wave detections to determine whether an R-wave detection should be classified as an erroneous R-wave detection (caused by P-wave or T-wave oversensing). For a more specific example, according to some embodiments, the peak amplitudes associated with R-wave detections are compared with each other to determine whether one of a first TWO or PWO morphological criterion or a second TWO or PWO morphological criterion is met, and if so, the R-wave detection is classified as an erroneous R-wave detection (caused by P-wave or T-wave oversensing). Figure 6 An example high-level flowchart of this embodiment is shown. (Reference) Figure 6 Step 602 involves obtaining the associated peak amplitude A(n) for the R-wave detection. Steps 332 and 342 are used to determine whether a first TWO or PWO morphological criterion is met. If the first TWO or PWO morphological criterion is met, the answer to the determination in step 342 will be "yes," and in step 352, the R-wave detection will be classified as an erroneous R-wave detection. If the first TWO or PWO morphological criterion is not met, steps 382 and 392 are used to determine whether a second TWO or PWO morphological criterion is met. If the second TWO or PWO morphological criterion is met, the answer to the determination in step 392 will be "yes," and in step 352, the R-wave detection will be classified as an erroneous R-wave detection. If neither the first TWO or PWO morphological criterion nor the second TWO or PWO morphological criterion is met, then in step 394, the R-wave detection will not be classified as an erroneous R-wave detection. Figure 6 Steps 332, 342, 352, 382, ​​392, and 394 shown have been described above with reference to Figure 3 and therefore do not need to be described again. Some additional example details of how to perform these steps are described above with reference to Figure 4.

[0073] Figure 7 Includes a more general explanation of how to use the first TWO or PWO morphological criterion and the second TWO or PWO morphological criterion to determine whether an R-wave detection should be classified as an erroneous R-wave detection due to TWO or PWO. Reference Figure 7Step 702 involves obtaining a specific type of morphological feature associated with R-wave detection. According to a particular embodiment, the specific type of morphological feature includes peak amplitude. When the specific type of morphological feature includes peak amplitude, step 702 is the same as step 602 described above. Alternative types of morphological features that can be obtained in step 702 include, but are not limited to, the area under the curve (AUC) associated with R-wave detection, the width (W) associated with R-wave detection, or the maximum slope (MS) associated with R-wave detection. The width (W) can be, for example, the following measurements associated with the corresponding R-wave detection: full width at the R-wave threshold detection intersection, full width at half maximum (FWHM), or half width at half maximum (HWHM), but is not limited thereto. As described above, the maximum slope (MS) associated with R-wave detection can be determined by determining the maximum derivative (dV / dt) of the ECG or EGM signal within a window around or after R-wave detection. Such a window can be, for example, a window from 50 milliseconds before R-wave detection to 50 milliseconds after R-wave detection, but is not limited thereto.

[0074] Still referencing Figure 7 Step 732 involves comparing a specific morphological feature (e.g., peak amplitude) associated with the R-wave detection with a specific morphological feature associated with each R-wave detection in the first set of earlier detected R-wave detections to determine whether a first TWO or PWO morphological criterion is met. In some embodiments, the first set of earlier detected R-wave detections includes R-wave detections that are one, two, or three times earlier than the first set of detected R-wave detections. Step 732 is the same as step 332 described above when a specific type of morphological feature includes peak amplitude and the first set of earlier detected R-wave detections includes R-wave detections that are one, two, or three times earlier than the first set of detected R-wave detections. In step 742, it is determined whether the first TWO or PWO morphological criterion is met. If the answer to the determination in step 742 is "yes," the process proceeds to step 752, and the R-wave detection is classified as an erroneous R-wave detection caused by TWO or PWO. If the answer to the determination in step 742 is "no," the process proceeds to step 782.

[0075] Step 782 involves comparing a specific morphological feature (e.g., peak amplitude) associated with the R-wave detection with a specific morphological feature associated with each of the earlier R-wave detections in the second group to determine whether a second TWO or PWO morphological criterion is met, wherein the second group differs from the first group but may have some overlap with the first group. In some embodiments, the earlier R-wave detections in the second group include R-wave detections that are two, three, or four R-wave detections earlier. Step 782 is the same as step 382 described above when a specific type of morphological feature includes peak amplitude and the earlier R-wave detections in the second group include R-wave detections that are two, three, or four R-wave detections earlier. In step 792, it is determined whether the second TWO or PWO morphological criterion is met. If the answer to the determination in step 792 is "yes," the process proceeds to step 752, and the R-wave detection is classified as an erroneous R-wave detection caused by TWO or PWO. If the answer to the determination in step 792 is "no," the process proceeds to step 794, and the R-wave detection is not classified as an erroneous R-wave detection.

[0076] According to certain embodiments, one of the above-described techniques for determining whether an R-wave detection should be classified as an erroneous R-wave detection (due to TWO or PWO) can be performed in real time, such that each time an R-wave detection occurs, before the next R-wave detection occurs, it is determined whether the R-wave detection should be classified as an erroneous R-wave detection. In some such embodiments, whenever an R-wave detection occurs, a preliminary rhythm classification of the R-wave detection is established based on the RR interval associated with the R-wave detection, and a label for the preliminary classification (e.g., bradycardia, normal sinus rhythm, VT, or VF) can be generated and stored along with information about the R-wave detection (e.g., associated RR interval duration, peak amplitude, etc.). For example, the preliminary rhythm classification can be determined by determining which rate zone or RR interval range the R-wave detection is appropriate to, wherein for each of a plurality of different rhythms (e.g., but not limited to normal sinus rhythm, bradycardia, VT, and VF), there can be a separate rate zone or RR interval range. In some IMDs, in response to a threshold number of R-wave detections (within a specified time period or a specific number of R-wave detections) being classified as a type of arrhythmia (e.g., VT), that type of arrhythmia (e.g., VT) will be detected (and possibly treated). For example, if 8 out of the last 12 R-wave detections are classified as VT, the IMD can detect a VT episode and deliver antitachycardia pacing (ATP) therapy to attempt to convert the VT episode to a normal sinus rhythm. As another example, if 8 out of the last 12 R-wave detections are classified as VF, the IMD can detect a VF episode and deliver a defibrillation shock to attempt to convert the VF episode to a normal sinus rhythm. This can be achieved, for example, by incrementing an appropriate counter (such as a VT counter or a VF counter) in response to an initial classification of the R-wave detection as a VT or VF rhythm. In cases where one of the aforementioned techniques is used to classify an R-wave detection as an erroneous R-wave detection (due to TWO or PWO), the R-wave detection cannot be used to increment any of the aforementioned counters, the R-wave detection is classified as unclassified, and / or the label of the R-wave detection (e.g., VT label or VF label) is discarded (also known as removal). Real-time correction of these labels is beneficial because it does not interfere with the arrhythmia detection algorithm and also improves downstream diagnosis.

[0077] In an alternative embodiment, upon detection of an arrhythmia, one of the aforementioned techniques for determining whether an R-wave detection should be classified as an erroneous R-wave detection (due to TWO or PWO) can be executed to determine whether the arrhythmia detection should be rejected because it may be an erroneous arrhythmia detection. For example, once the IMD detects a VT, the IMD can analyze the R-wave detections within the window that led to the VT detection to determine whether and / or to what extent the R-wave detections within the window are erroneous R-wave detections. Then, if at least a threshold number of R-wave detections are classified as erroneous R-wave detections, the arrhythmia detection can be classified as an erroneous arrhythmia detection, and treatment of the arrhythmia can be suspended. For a particular example implementation, an "oversensing score" can be calculated as the percentage of R-wave detection events classified as oversensing within a specified pre-detection window. If the "oversensing score" exceeds a threshold, the arrhythmia detection can be rejected, and any treatment can be blocked or suspended. Other variations are also possible and are within the scope of the embodiments described herein.

[0078] Alternatively, R-wave detections classified as erroneous R-wave detections can be discarded, and one or more arrhythmia algorithms can be rerun to check whether the original arrhythmia detection should be confirmed or rejected. For example, upon detecting an arrhythmia, a pre-detection window (e.g., a 30-second window that led to the arrhythmia detection) is analyzed to determine if any oversensitized R-wave detection events exist within the pre-detection window. If one or more oversensitized events are identified, the oversensitized events can be discarded to produce a corrected pre-detection window. The corrected pre-detection window can then be analyzed to determine whether the arrhythmia detection was a true positive or a false positive. In other words, any arrhythmia detection algorithm(s) used to provide the initial arrhythmia detection can be rerun on the corrected pre-detection window. Other variations are also possible and are within the scope of the embodiments described herein.

[0079] According to certain embodiments of the present technology, the R-wave detection threshold and / or other types of R-wave sensing parameters can be adjusted based on whether and / or to what extent the R-wave detection is classified as an erroneous R-wave detection due to TWO or PWO. For example, if at least a threshold number of R-wave detections within a specified number of R-wave detections (or within a specified amount of time) are classified as erroneous R-wave detections due to PWO, the R-wave detection threshold can be increased to reduce the chance of PWO. Alternatively, or additionally, if at least a threshold number of R-wave detections within a specified number of R-wave detections (or within a specified amount of time) are classified as erroneous R-wave detections due to TWO, the delayed decay of the R-wave detection threshold can be extended to reduce the chance of TWO, wherein the decay delay defines the period during which the amplitude or sensitivity level of the R-wave detection threshold remains constant after the refractory period expires and before the R-wave detection threshold begins to decrease in real time. Other variations are also possible and are within the scope of the embodiments described herein.

[0080] According to certain embodiments of this technology, PWO and / or TWO detection criteria can be dynamically adjusted based on whether and / or to what extent an R-wave detection is classified as an erroneous R-wave detection due to a TWO or TWO event. For example, one of the techniques described above can be performed in real time for a recently detected R-wave detection, and one or more histograms can be generated to track RT interval variations and T-wave amplitude variations. Then, when a newly detected R-wave detection has an associated RR interval duration and associated peak amplitude (and / or some other morphological features) within the range of one of the generated histograms, the R-wave detection criteria can be adjusted because the R-wave detection is more likely to be another TWO or PWO event. Other variations are also possible and are within the scope of the embodiments described herein.

[0081] According to certain embodiments, the IMD can perform the above-mentioned reference figures 3 to 4 in response to the detection of an arrhythmia episode. Figure 7 One method described. Detection of arrhythmia episodes can also be referred to as arrhythmia triggering. Such an IMD can be configured to transmit data corresponding to the arrhythmia episode detected by the IMD to an external device communicatively coupled to the patient care network. In some such embodiments, the IMD does not (is blocked) from transmitting data corresponding to the arrhythmia episode detected by the IMD (to the external device communicatively coupled to the patient care network), but this data is subsequently identified by the IMD as a false positive detection.

[0082] According to certain embodiments, the above-described reference figures 3 to 4 are executed. Figure 7A medical device (e.g., an IMD) using one of these methods can monitor a patient's heart rate (HR) based on an interval identified from a segment of an EGM or ECG, and the device can determine, based on the results of the method, whether the monitored HR is inaccurate due to oversensing and should therefore be ignored or recalculated. For example, if the oversensing score exceeds a corresponding threshold, the device can determine that the HR determined based on the sensed interval is inaccurate and should not be used, or should be recalculated.

[0083] Embodiments of the technology described herein can be used with various types of IMDs, including but not limited to insertable cardiac monitors (ICMs), pacemakers with one or more leads attached, leadless pacemakers (LCPs), or implantable cardioverter defibrillators (ICDs). Such IMDs can be transvascular or nonvascular, wherein nonvascular IMDs can be subcutaneous (SubQ) IMDs. When embodiments of the technology are implemented using an IMD, these embodiments can be used, for example, to reduce the number of false positive AF detections transmitted from the IMD to the patient care network for review by clinicians. This is beneficial because false positive AF detections are highly undesirable, as the burden of sorting out a large number of clinically unrelated AF episodes can be both time-consuming and expensive. When embodiments of the technology are used with an IMD or an IMD communicating with an IMD, these embodiments can reduce the frequency of delivery of antitachycardia pacing (ATP) and / or defibrillation shocks in response to false positive tachycardia detections. This is beneficial because defibrillation shocks are usually painful, and delivering such a shock while the patient is awake in response to a false positive tachycardia detection would subject the patient to unnecessary pain or discomfort and could prematurely deplete the energy stored in the battery.

[0084] Figure 8 A block diagram of one embodiment of an IMD implanted in a patient according to a certain embodiment of the present technology is shown. The IMD 801 can be implemented as a full-function biventricular pacemaker equipped with both atrial and ventricular sensing and pacing circuitry for four-chamber sensing and stimulation therapy (including both pacing and electrical shock therapy). Optionally, the IMD 801 can provide full-function cardiac resynchronization therapy. Optionally, the IMD 801 can be implemented with a simplified set of functions and components. For example, if the IMD is an ICM, the IMD can be implemented without pacing. The IMD 801 can be coupled to one or more leads for single-chamber or multi-chamber pacing and / or sensing. Alternatively, the IMD 801 can be an LCP including electrodes located at or very close to the housing 800 of the IMD 801.

[0085] The IMD 801 has a housing 800 that houses electronic / computing components. The housing 800 (which is commonly referred to as a “can,” “box,” “shell,” or “box electrode”) can be programmably selected to act as a return electrode for certain stimulation modes. The housing 800 may further include connectors (not shown) having multiple terminals 802, 804, 806, 808, and 810. The terminals can be connected to electrodes located at different positions on the housing 800, or to electrodes located on leads. The electrodes to which terminals 802, 804, 806, 808, and 810 are connected can also be designated using reference numerals 802, 804, 806, 808, and 810, respectively, and “box electrode” can refer to box electrode 800. The IMD 801 includes a programmable microcontroller 820 that controls various operations of the IMD 801, including cardiac monitoring and / or stimulation therapy. The microcontroller 820 includes a microprocessor (or equivalent control circuitry), RAM and / or ROM memory, logic and timing circuitry, state machine circuitry, and I / O circuitry.

[0086] The IMD 801 also includes a pulse generator 822 that generates stimulation pulses and communication pulses for delivery via two or more electrodes coupled thereto. The pulse generator 822 is controlled by a microcontroller 820 via a control signal 824. The pulse generator 822 can be coupled to multiple selection electrodes via an electrode configuration switch 826, which includes multiple switches for connecting the desired electrode to appropriate I / O circuitry, thereby facilitating electrode programmability. The switch 826 is controlled by a control signal 828 from the microcontroller 820.

[0087] exist Figure 8 In one embodiment, a single pulse generator 822 is illustrated. Alternatively, the IMD may include multiple pulse generators, similar to pulse generator 822, wherein each pulse generator is coupled to two or more electrodes and controlled by microcontroller 820 to deliver selected stimulation pulses to the corresponding two or more electrodes.

[0088] Microcontroller 820 is shown to include timing control circuitry 832 for controlling the timing of stimulation pulses (e.g., pacing rate, atrioventricular (AV) delay, atrial (AA) conduction delay, or ventricular (VV) conduction delay, etc.). Timing control circuitry 832 can also be used for timing refractory periods, blanking intervals, noise detection windows, evoked response windows, alarm intervals, marker channel timing, etc. Microcontroller 820 also has an arrhythmia detector 834 and a morphology detector 836 for detecting arrhythmia conditions. Although not shown, microcontroller 820 may also include other dedicated circuitry and / or firmware / software components that aid in monitoring various conditions of the patient's heart and managing pacing therapy. Microcontroller 820 is also shown to include an oversensing detector 840, which can be used to perform the above-mentioned references. Figure 1-7 Any embodiment of the present technology described herein. The oversensing detector 840 may more generally be implemented using hardware, software, firmware, and / or a combination thereof. The microcontroller may include a processor. The microcontroller and / or its processor may be used to perform the methods of the present technology described herein.

[0089] The IMD 801 may be further equipped with a communication modem (modulator / demodulator) to enable wireless communication with a remote pacemaker. The modem may include one or more transmitters and two or more receivers. In one implementation, the modem may use low-frequency or high-frequency modulation. As an example, the modem may transmit implant-to-implant (i2i) messages and other signals via conductive communication between a pair of electrodes. Such a modem may be implemented in hardware as part of the microcontroller 820, or as software / firmware instructions programmed into and executed by the microcontroller 820. Alternatively, the modem may reside as a separate component from the microcontroller.

[0090] The IMD 801 includes sensing circuitry 844, selectively coupled via switch 826 to two or more electrodes performing sensing operations to detect the presence of cardiac activity in the right ventricle of the heart. Sensing circuitry 844 may include a dedicated sensing amplifier, a multiplexed amplifier, or a shared amplifier. It may also employ one or more low-power precision amplifiers with programmable gain and / or automatic gain control, bandpass filtering, and threshold detection circuitry to selectively sense cardiac signals of interest. Automatic gain control enables the unit to sense low-amplitude signal characteristics of atrial fibrillation. Switch 826 determines the sensing polarity of the cardiac signal by selectively closing an appropriate switch. This allows clinicians to program the sensing polarity independently of the stimulus polarity.

[0091] The output of sensing circuit 844 is connected to microcontroller 820, which in turn triggers or inhibits pulse generator 822 in response to the presence or absence of cardiac activity. Sensing circuit 844 receives control signal 846 from microcontroller 820 for timing control of gain, threshold, polarization charge removal circuit (not shown), and any blocking circuits (not shown) coupled to the input of sensing circuit.

[0092] exist Figure 8 In the embodiments illustrated, a single sensing circuit 844 is shown. Optionally, the IMD may include multiple sensing circuits, similar to sensing circuit 844, wherein each sensing circuit is coupled to two or more electrodes and controlled by microcontroller 820 to sense electrical activity detected at the corresponding two or more electrodes. Sensing circuit 844 may operate in a unipolar sensing configuration or a bipolar sensing configuration.

[0093] The IMD 801 also includes an analog-to-digital (A / D) data acquisition system (DAS) 850, which is coupled to two or more electrodes via a switch 826 to sample cardiac signals on any desired pair of electrodes. The data acquisition system 850 is configured to acquire intracardiac electrogram signals, convert raw analog data into digital data, and store the digital data for subsequent processing and / or telemetry transmission to an external device 854 (e.g., a programmer, local transceiver, or diagnostic system analyzer). The data acquisition system 850 is controlled by control signals 856 from a microcontroller 820.

[0094] The microcontroller 820 is coupled to the memory 860 via a suitable data / address bus. Programmable operating parameters used by the microcontroller 820 are stored in the memory 860 and are used to customize the operation of the IMD 801 to suit the needs of a specific patient. These operating parameters define, for example, pacing pulse amplitude, pulse duration, electrode polarity, rate, sensitivity, auto-sensing characteristics, arrhythmia detection criteria, and the amplitude, waveform, and vector of each electrical shock pulse to be delivered to the patient's heart 612 within each corresponding level of treatment.

[0095] The operating parameters of the IMD 801 can be non-invasively programmed into the memory 860 via the telemetry circuit 864, which communicates telemetryally with the external device 854 via the communication link 866. The telemetry circuit 864 allows electrocardiograms and status information associated with the operation of the IMD 801 (such as those contained in the microcontroller 820 or the memory 860) to be transmitted to the external device 854 via the communication link 866.

[0096] The IMD 801 may also include a magnet detection circuit (not shown) coupled to the microcontroller 820 for detecting when a magnet is placed on the unit. Clinicians can use the magnet to perform various test functions of the IMD 801 and / or signal the microcontroller 820 that an external device 854 is in place to receive or transmit data to the microcontroller 820 via telemetry circuitry 864.

[0097] The IMD 801 may further include one or more physiological sensors 870. These sensors are often referred to as “rate-responsive” sensors because they are typically used to adjust the pacing stimulation rate based on the patient’s exercise status. However, the physiological sensors 870 may further be used to detect changes in cardiac output, changes in cardiac physiology, or diurnal variations in activity (e.g., detecting sleep and wakefulness). Signals generated by the physiological sensors 870 are passed to a microcontroller 820 for analysis. The microcontroller 820 responds by adjusting various pacing parameters (such as rate, AV delay, VV delay, etc.) applied by the atrial and ventricular pacing pulses. Although shown as being included within the IMD 801, one or more physiological sensors 870 may be external to the IMD 801 but still implanted in or carried by the patient. Examples of physiological sensors include sensors for sensing respiratory rate, blood pH, ventricular gradient, activity, position / posture, minute ventilation (MV), etc.

[0098] Battery 872 provides operating power to all components in IMD 801. Battery 872 is preferably capable of long-term operation with low current consumption and of providing high-current pulses (for capacitor charging) when the patient requires a shock pulse (e.g., exceeding 2A, voltage above 2V, lasting 10 seconds or longer). Battery 872 also desirously has predictable discharge characteristics, allowing for the detection of selective replacement times. As an example, IMD 801 employs a lithium / silver vanadium oxide battery.

[0099] The IMD 801 also includes impedance measurement circuitry 874, which can be used for a variety of purposes, including: monitoring lead impedance during the acute and chronic phases for proper lead positioning or displacement; detecting operable electrodes and automatically switching to an operable electrode pair if displacement occurs; measuring respiratory rate or minute ventilation; measuring chest impedance to determine the shock threshold; detecting when the device is implanted; measuring stroke volume; and detecting the opening of heart valves, etc. Impedance measurement circuitry 874 is coupled to switch 826, allowing the use of any desired electrode. In this embodiment, the IMD 801 also includes shock circuitry 880 coupled to microcontroller 820 via data / address bus 882.

[0100] The embodiments of the present technology described above are primarily used with implantable medical devices or systems that monitor heart rate (HR) based on sensed intervals and / or for one or more types of arrhythmia episodes, whereby, as mentioned above, the sensed intervals can be true RR intervals or oversensitized RR intervals. These embodiments of the present technology can alternatively be used with non-implantable devices or systems (also referred to as external devices or systems) that include at least two electrodes in contact with human skin and are used to monitor HR based on sensed intervals and / or for one or more types of arrhythmia episodes. More specifically, such embodiments can alternatively be used with or implemented by user wearable devices, such as wrist-worn devices, or user wearable devices designed to be worn on one or more other parts of the human body besides the wrist (e.g., on the ankle, upper arm, or chest), but are not limited thereto. Such user wearable devices may include electrodes configured to contact human skin, sensing circuitry coupled to the electrodes and configured to receive signals indicative of electrical activity in the patient's heart, and at least one processor or controller configured to execute one or more of the algorithms described above. This user-wearable device (or more generally, an external device or system) can monitor atrial fibrillation (AF) and / or other types of arrhythmias(s) and determine when false positives are detected. Additionally or alternatively, this user-wearable device (or more generally, an external device or system) can monitor a person's heart rate (HR) and determine when HR measurements may be inaccurate due to oversensing. The user-wearable device can acquire signals indicative of the electrical activity of a patient's heart and can monitor a person's HR and / or(s) arrhythmias based on intervals obtained from the acquired signals. Optionally, the user-wearable device can be communicatively coupled to another external device, such as a smartphone or tablet, and the other external device can acquire signals from the user-wearable device and monitor a person's HR and / or(s) arrhythmias based on intervals. The user-wearable device or other external device or system can determine when false positives may occur and / or when the measured HR may be inaccurate due to oversensing. Other implementations of this external device or system are also possible and are within the scope of the embodiments described herein.

[0101] It should be understood that the subject matter described herein is not limited to its application to the construction details and arrangement of components set forth in the description or shown in the accompanying drawings. The subject matter described herein can have other embodiments and can be practiced or performed in various ways. Furthermore, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be considered limiting. The use of “comprising,” “including,” or “having,” and variations thereof herein is intended to cover the items listed thereafter and their equivalents, as well as additional items. Additionally, it should be noted that, unless otherwise stated, the term “based on” as used herein should be interpreted as meaning at least partially based on, indicating that there may be one or more additional factors, such as those upon which decisions are made. For example, if a decision is based on the results of a comparison, then the decision may be based on one or more other factors besides the results of the comparison.

[0102] Embodiments of this technology have been described with the aid of functional building blocks illustrating the performance of specified functions and their relationships. For ease of description, the boundaries of these functional building blocks are frequently defined herein. Alternative boundaries can be defined as long as the specified functions and their relationships are properly performed. Therefore, any such alternative boundaries are within the scope and spirit of the claimed invention. For example, they can be combined or separated. Figures 2 to 7 Some of the steps shown are illustrated. It is also possible to record some of the steps shown in Figures 3 through 7. For another example, the steps can be modified. Figure 8 The boundaries of some of the boxes shown.

[0103] The specific thresholds mentioned above (e.g., percentage thresholds, ratio thresholds, less than a specified level, etc.) are provided as examples only and can be system-optimized for a broader patient population or for individual patients. Therefore, embodiments of the technology described herein should not be limited to use with the exemplary thresholds described herein.

[0104] It should be understood that the above description is intended to be illustrative and not limiting. For example, the above embodiments (and / or aspects thereof) can be used in combination with each other. Furthermore, many modifications can be made to adapt particular situations or materials to the teachings of embodiments of the present technology without departing from the scope of the present technology. While the dimensions, material types, and coatings described herein are intended to define parameters of embodiments of the present technology, they are by no means limiting but rather exemplary embodiments. Many other embodiments will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of embodiments of the present technology should be determined by reference to the appended claims and the full scope of their equivalents. In the appended claims, the terms “comprising” and “wherein” are used as concise equivalents to the corresponding terms “including” and “therein”. Furthermore, in the following claims, the terms “first,” “second,” and “third,” etc., are used merely as labels and are not intended to impose numerical requirements on their objects. Moreover, the limitations of the following claims are not written in a component-plus-function format and are not intended to be interpreted based on 35U.SC112(f), unless and until such a claim expressly uses the phrase “component, for” followed by a functional statement without further structure.

Claims

1. A method for determining whether an R-wave detection should be classified as an erroneous R-wave detection due to T-wave oversensing (TWO) or P-wave oversensing (PWO), the method comprising: The specific morphological features associated with the R-wave detection are compared with the specific morphological features associated with each of the earlier R-wave detections in a first group of R-wave detections, including R-wave detections that are earlier than one, two, and three times, to determine whether a first TWO or PWO morphological criterion is met. The specific morphological features associated with the R-wave detection are compared with the specific morphological features associated with each of the earlier R-wave detections in a second group of R-wave detections, including R-wave detections that are earlier than two, three, and four times, to determine whether a second TWO or PWO morphological criterion is met, wherein the second group is different from the first group but has some overlap with the first group. as well as In response to satisfying either the first TWO or PWO morphological standard or the second TWO or PWO morphological standard, the R-wave detection is classified as an erroneous R-wave detection.

2. The method according to claim 1, wherein: The specific morphological feature includes peak amplitude A; The first TWO or PWO morphological criterion is satisfied when the peak amplitude A(n) associated with the R-wave detection is at least lower than the peak amplitude A(n-1) associated with an R-wave detection one R-wave earlier, at least not lower than the peak amplitude A(n-2) associated with an R-wave detection two R-wave earlier, and at least lower than the peak amplitude A(n-3) associated with an R-wave detection three R-wave earlier; and The second TWO or PWO morphological standard is satisfied when the peak amplitude A(n) associated with the R-wave detection is at least lower than the peak amplitude A(n-2) associated with an R-wave detection two R-wave detections earlier, at least not lower than the peak amplitude A(n-3) associated with an R-wave detection three R-wave detections earlier, and at least lower than the peak amplitude A(n-4) associated with an R-wave detection four R-wave detections earlier.

3. The method according to claim 1, wherein: The specific morphological feature includes the area under the curve (AUC); The first TWO or PWO morphological criterion is satisfied when the AUC(n) associated with the R-wave detection is at least a specified amount smaller than the AUC(n-1) associated with an R-wave detection one R-wave earlier, at least not a specified amount smaller than the AUC(n-2) associated with an R-wave detection two R-wave earlier, and at least a specified amount smaller than the AUC(n-3) associated with an R-wave detection three R-wave earlier; and The second TWO or PWO morphological criterion is satisfied when the AUC(n) associated with the R-wave detection is at least as small as the AUC(n-2) associated with an R-wave detection that occurred two R-waves earlier, at least as small as the AUC(n-3) associated with an R-wave detection that occurred three R-waves earlier, and at least as small as the AUC(n-4) associated with an R-wave detection that occurred four R-waves earlier.

4. The method according to claim 1, wherein: The specific morphological feature includes width W; The first TWO or PWO morphological standard is satisfied when the width W(n) associated with the R-wave detection is at least longer than the width W(n-1) associated with an R-wave detection that occurred one R-wave earlier, at least not longer than the width W(n-2) associated with an R-wave detection that occurred two R-wave earlier, and at least longer than the width W(n-3) associated with an R-wave detection that occurred three R-wave earlier. The second TWO or PWO morphological criterion is satisfied when the width W(n) associated with the R-wave detection is at least longer than the width (n-2) associated with an R-wave detection two R-waves earlier, at least not longer than the width W(n-3) associated with an R-wave detection three R-waves earlier, and at least longer than the width W(n-4) associated with an R-wave detection four R-waves earlier; and Each of the widths can be one of the following measurements associated with the corresponding R-wave detection: full width at the threshold detection intersection, full width at half maximum (FWHM), or half width at half maximum (HWHM).

5. The method according to claim 1, wherein: The specific morphological feature includes the maximum slope MS; The first TWO or PWO morphological criterion is satisfied when the MS(n) associated with the R-wave detection is at least smaller than the MS(n-1) associated with an R-wave detection one R-wave earlier, at least not smaller than the MS(n-2) associated with an R-wave detection two R-wave earlier, and at least smaller than the MS(n-3) associated with an R-wave detection three R-wave earlier; and the MS(n-1) associated with the R-wave detection three R-wave earlier. The second TWO or PWO morphological criterion is satisfied when the MS(n) associated with the R-wave detection is at least smaller than the MS(n-2) associated with an R-wave detection that occurred two R-waves earlier, at least not smaller than the MS(n-3) associated with an R-wave detection that occurred three R-waves earlier, and at least smaller than the MS(n-4) associated with an R-wave detection that occurred four R-waves earlier.

6. The method according to any one of claims 1 to 5, wherein, The step of determining whether to classify the R-wave detection as an erroneous R-wave detection includes classifying the R-wave detection as an erroneous R-wave detection in response to satisfying one of the first TWO or PWO morphological criteria or the second TWO or PWO morphological criteria.

7. The method according to any one of claims 1 to 5, further comprising: The duration of the RR interval associated with the R-wave detection is compared with the duration of the RR interval associated with each of the earlier R-wave detections in the third group to determine whether a first TWO or PWO timing criterion is met; and the duration of the RR interval associated with the R-wave detection is compared with the duration of the RR interval associated with each of the earlier R-wave detections in the fourth group to determine whether a second TWO or PWO timing criterion is met, wherein the fourth group is different from the third group; and The classification of the R-wave detection as an erroneous R-wave detection is also determined based on whether one of the first TWO or PWO time criterion or the second TWO or PWO time criterion is met.

8. The method according to claim 7, wherein: The third group of earlier detected R-wave detections includes R-wave detections that were one or two R-wave detections earlier; The fourth group of earlier detected R-wave detections includes R-wave detections that were two or three R-wave detections earlier; The first TWO or PWO timing criterion is satisfied when the RR interval duration D(n) associated with the R-wave detection is not similar to the RR interval duration D(n-1) associated with an R-wave detection that was one R-wave detection earlier, but is similar to the RR interval duration D(n-2) associated with an R-wave detection that was two R-wave detections earlier; and The second TWO or PWO timing criterion is satisfied when the duration of the RR interval D(n) associated with the R-wave detection is not similar to the duration of the RR interval D(n-2) associated with an R-wave detection that is two R-wave detections earlier, but is similar to the duration of the RR interval D(n-3) associated with an R-wave detection that is three R-wave detections earlier.

9. The method of claim 8, wherein determining whether to classify the R-wave detection as an erroneous R-wave detection includes classifying the R-wave detection as an erroneous R-wave detection in response to: It satisfies both the first TWO or PWO morphological standard and the first TWO or PWO temporal standard; or It satisfies both the second TWO or PWO morphological standard and the second TWO or PWO temporal standard.

10. An apparatus for determining whether an R-wave detection should be classified as an erroneous R-wave detection due to T-wave oversensing (TWO) or P-wave oversensing (PWO), comprising: Two or more electrodes; A sensing circuit, coupled to the two or more electrodes, is configured to acquire a signal indicative of the electrical activity of the patient's heart; as well as Processor or controller; R-wave detection is performed by comparing a signal or a sample of the signal indicative of the patient's cardiac electrical activity with an R-wave detection threshold; and In order to determine whether the R-wave detection should be classified as an erroneous R-wave detection due to T-wave oversensing (TWO) or P-wave oversensing (PWO), the processor or controller is configured to: The specific morphological features associated with the R-wave detection are compared with those associated with each of the earlier R-wave detections in a first group of R-wave detections, including R-wave detections that are one, two, and three R-wave detections earlier, to determine whether a first TWO or PWO morphological criterion is met. The specific morphological features associated with the R-wave detection are also compared with those associated with each of the earlier R-wave detections in a second group of R-wave detections, including R-wave detections that are two, three, and four R-wave detections earlier, to determine whether a second TWO or PWO morphological criterion is met, wherein the second group differs from the first group but overlaps with it to some extent. In response to satisfying either the first TWO or PWO morphological standard or the second TWO or PWO morphological standard, the R-wave detection is classified as an erroneous R-wave detection.

11. The device according to claim 10, wherein: The specific morphological feature includes peak amplitude A; The processor or controller is configured to determine that the first TWO or PWO morphological criterion is satisfied when the peak amplitude A(n) associated with the R-wave detection is at least lower than the peak amplitude A(n-1) associated with an R-wave detection one R-wave earlier, at least not lower than the peak amplitude A(n-2) associated with an R-wave detection two R-wave earlier, and at least lower than the peak amplitude A(n-3) associated with an R-wave detection three R-wave earlier; and The processor or controller is configured to determine that the second TWO or PWO morphological standard is satisfied when the peak amplitude A(n) associated with the R-wave detection is at least lower than the peak amplitude A(n-2) associated with an R-wave detection two R-wave detections earlier, at least not lower than the peak amplitude A(n-3) associated with an R-wave detection three R-wave detections earlier, and at least lower than the peak amplitude A(n-4) associated with an R-wave detection four R-wave detections earlier.

12. The device according to claim 10, wherein: The specific morphological feature includes the area under the curve (AUC); The processor or controller is configured to determine that the first TWO or PWO morphological criterion is satisfied when the AUC(n) associated with the R-wave detection is at least as small as the AUC(n-1) associated with an R-wave detection one R-wave earlier, at least not as small as the AUC(n-2) associated with an R-wave detection two R-wave earlier, and at least as small as the AUC(n-3) associated with an R-wave detection three R-wave earlier; and The processor or controller is configured to determine that the second TWO or PWO morphological criterion is satisfied when the AUC(n) associated with the R-wave detection is at least as small as the AUC(n-2) associated with an R-wave detection that occurred two R-waves earlier, at least as small as the AUC(n-3) associated with an R-wave detection that occurred three R-waves earlier, and at least as small as the AUC(n-4) associated with an R-wave detection that occurred four R-waves earlier.

13. The device according to claim 10, wherein: The specific morphological feature includes width W; The processor or controller is configured to determine that the first TWO or PWO morphological standard is satisfied when the width W(n) associated with the R-wave detection is at least longer than the width W(n-1) associated with an R-wave detection one R-wave earlier by a specified degree, at least not longer than the width W(n-2) associated with an R-wave detection two R-wave earlier by the specified degree, and at least longer than the width W(n-3) associated with an R-wave detection three R-wave earlier by the specified degree. The processor or controller is configured to determine that the second TWO or PWO morphological standard is satisfied when the width W(n) associated with the R-wave detection is at least longer than the width (n-2) associated with an R-wave detection two R-wave detections earlier by a specified degree, at least not longer than the width W(n-3) associated with an R-wave detection three R-wave detections earlier by a specified degree, and at least longer than the width W(n-4) associated with an R-wave detection four R-wave detections earlier; and Each of the widths can be one of the following measurements associated with the corresponding R-wave detection: full width at the threshold detection intersection, full width at half maximum (FWHM), or half width at half maximum (HWHM).

14. The device according to claim 10, wherein: The specific morphological feature includes the maximum slope MS; The processor or controller is configured to determine that the first TWO or PWO morphological criterion is satisfied when the MS(n) associated with the R-wave detection is at least smaller by a specified amount than the MS(n-1) associated with an R-wave detection one R-wave earlier, at least not smaller by the specified amount than the MS(n-2) associated with an R-wave detection two R-wave earlier, and at least smaller by the specified amount than the MS(n-3) associated with an R-wave detection three R-wave earlier; and The processor or controller is configured to determine that the second TWO or PWO morphological criterion is satisfied when the MS(n) associated with the R-wave detection is at least as small as the MS(n-2) associated with an R-wave detection that occurred two R-waves earlier, at least as small as the MS(n-3) associated with an R-wave detection that occurred three R-waves earlier, and at least as small as the MS(n-4) associated with an R-wave detection that occurred four R-waves earlier.

15. The device according to any one of claims 10 to 14, wherein, The processor or controller is configured to classify the R-wave detection as an erroneous R-wave detection in response to satisfying either the first TWO or PWO morphological standard or the second TWO or PWO morphological standard.

16. The device according to any one of claims 10 to 14, wherein, The processor or controller is also configured to: The duration of the RR interval associated with the R-wave detection is compared with the duration of the RR interval associated with each of the earlier R-wave detections in the third group to determine whether a first TWO or PWO timing criterion is met; and the duration of the RR interval associated with the R-wave detection is compared with the duration of the RR interval associated with each of the earlier R-wave detections in the fourth group to determine whether a second TWO or PWO timing criterion is met, wherein the fourth group is different from the third group; and The classification of the R-wave detection as an erroneous R-wave detection is also determined based on whether one of the first TWO or PWO time criterion or the second TWO or PWO time criterion is met.

17. The apparatus according to claim 16, wherein: The third group of earlier detected R-wave detections includes R-wave detections that were one or two R-wave detections earlier; The fourth group of earlier detected R-wave detections includes R-wave detections that were two or three R-wave detections earlier; The processor or controller is configured to determine that the first TWO or PWO timing criterion is met when the RR interval duration D(n) associated with the R-wave detection is not similar to the RR interval duration D(n-1) associated with an R-wave detection that was one R-wave detection earlier, but is similar to the RR interval duration D(n-2) associated with an R-wave detection that was two R-wave detections earlier; and The processor or controller is configured to determine that the second TWO or PWO timing criterion is met when the RR interval duration D(n) associated with the R-wave detection is not similar to the RR interval duration D(n-2) associated with an R-wave detection that is two R-wave detections earlier, but is similar to the RR interval duration D(n-3) associated with an R-wave detection that is three R-wave detections earlier.

18. The device of claim 17, wherein the processor or controller is configured to classify the R-wave detection as an erroneous R-wave detection in response to: It satisfies both the first TWO or PWO morphological standard and the first TWO or PWO temporal standard; or It satisfies both the second TWO or PWO morphological standard and the second TWO or PWO temporal standard.

19. The device according to any one of claims 10 to 14, wherein, The processor or controller is further configured to adjust at least one parameter of the R-wave detection threshold based on a determination of whether the R-wave detection should be classified as an erroneous R-wave detection due to TWO or PWO.

20. A method for determining whether an R-wave detection should be classified as an erroneous R-wave detection due to T-wave oversensing (TWO) or P-wave oversensing (PWO), the method comprising: Obtain the peak amplitude A(n) associated with the R-wave detection and the corresponding peak amplitudes of other R-wave detections prior to the R-wave detection; The first TWO or PWO morphological criterion is determined by determining whether the peak amplitude A(n) associated with the R-wave detection is at least lower than the peak amplitude A(n-1) associated with an R-wave detection one R-wave earlier, whether it is at least not lower than the peak amplitude A(n-2) associated with an R-wave detection two R-wave earlier, and whether it is at least lower than the peak amplitude A(n-3) associated with an R-wave detection three R-wave earlier. The second TWO or PWO morphological standard is determined by determining whether the peak amplitude A(n) associated with the R-wave detection is at least lower than the peak amplitude A(n-2) associated with an R-wave detection two R-waves earlier, whether it is at least not lower than the peak amplitude A(n-3) associated with an R-wave detection three R-waves earlier, and whether it is at least lower than the peak amplitude A(n-4) associated with an R-wave detection four R-waves earlier; and In response to satisfying either the first TWO or PWO morphological standard or the second TWO or PWO morphological standard, the R-wave detection is classified as an erroneous R-wave detection.

21. An apparatus for determining whether an R-wave detection should be classified as an erroneous R-wave detection due to T-wave oversensing (TWO) or P-wave oversensing (PWO), comprising: Two or more electrodes; A sensing circuit, coupled to the two or more electrodes, is configured to acquire a signal indicative of the electrical activity of the patient's heart; as well as The processor or controller is configured as follows: Obtain the peak amplitude A(n) associated with the R-wave detection and the corresponding peak amplitudes of other R-wave detections prior to the R-wave detection; The first T-wave oversensing TWO or P-wave oversensing PWO morphological criteria are determined by determining whether the peak amplitude A(n) associated with the R-wave detection is at least lower than the peak amplitude A(n-1) associated with an R-wave detection one R-wave earlier, whether it is at least not lower than the peak amplitude A(n-2) associated with an R-wave detection two R-wave earlier, and whether it is at least lower than the peak amplitude A(n-3) associated with an R-wave detection three R-wave earlier. The second TWO or PWO morphological standard is determined by determining whether the peak amplitude A(n) associated with the R-wave detection is at least lower than the peak amplitude A(n-2) associated with an R-wave detection two R-waves earlier, whether it is at least not lower than the peak amplitude A(n-3) associated with an R-wave detection three R-waves earlier, and whether it is at least lower than the peak amplitude A(n-4) associated with an R-wave detection four R-waves earlier; and In response to satisfying either the first TWO or PWO morphological standard or the second TWO or PWO morphological standard, the R-wave detection is classified as an erroneous R-wave detection.

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