616 results about "Hypsarrhythmia" patented technology

Analyzes surface electrocardiographic and intracardiac signals to identify and separate electrical activity corresponding to distinct but superimposed events in the heart. Assesses the spatial phase, temporal phase, rate, spectrum and reproducibility of each event to determine uniformity of activation in all spatial dimensions. Uses numerical indices derived from these analyses to diagnose arrhythmias. Uses these indices to determine the location of an arrhythmia circuit, and to direct the movement of an electrode catheter to this location for ablation or permanent catheter positioning. Subsequently, uses these indices to determine whether ablation has successfully eliminated the circuit. Uses variability in these indices from the surface electrocardiogram to indicate subtle beat-to-beat fluctuations which reflect the tendency towards atrial and ventricular arrhythmias.

An implantable stimulator and monitor measures a group of heart failure parameters indicative of the state of heart failure employing EGM signals, measures of blood pressure including absolute pressure P, developed pressure (DP=systolic P-diastolic P), and/or dP/dt, and measures of heart chamber volume (V) over one or more cardiac cycles. These parameters include: (1) relaxation or contraction time constant tau (.tau.); (2) mechanical restitution (MR), i.e., the mechanical response of a heart chamber to premature stimuli applied to the heart chamber; (3) recirculation fraction (RF), i.e., the rate of decay of PESP effects over a series of heart cycles; and (4) end systolic elastance (E.sub.ES), i.e., the ratios of end systolic blood pressure P to volume V. These heart failure parameters are determined periodically regardless of patient posture and activity level. The physician can determine whether a particular therapy is appropriate, prescribe the therapy for a period of time while again accumulating the stored patient data for a later review and assessment to determine whether the applied therapy is beneficial or not, thereby enabling periodic changes in therapy, if appropriate. Drug therapies and electrical stimulation therapies, including PESP stimulation, and pacing therapies including single chamber, dual chamber and multi-chamber (bi-atrial and/or bi-ventricular) pacing can be delivered. In patient's prone to malignant tachyarrhythmias, the assessment of heart failure state can be taken into account in setting parameters of detection or classification of tachyarrhythmias and the therapies that are delivered.

A system and method for detecting and discriminating atrial arrhythmias based on mechanical signals of cardiac wall motion and electrical signals of cardiac depolarizations. A mechanical event rate determined from sensed mechanical events is used to corroborate an electrical event rate determined from sensed EGM or ECG signals to classify the heart rhythm. If the event rates are not correlated, other parameterized data from the mechanical signal and electrical signal are evaluated to detect evidence of an arrhythmia. If electrical and mechanical event data do not corroborate a common arrhythmia condition, electrical and mechanical sensing parameters may be adjusted.

Systems and methods of detecting an impending cardiac decompensation of a patient measure an electrocardiogram signal of the patient. An incidence of cardiac arrhythmias is determined from the electrocardiogram signal. A risk of impending decompensation is determined in response to the incidence of cardiac arrhythmias. In many embodiments, the impending decompensation can be detected early enough to avoid, or at least delay, the impending decompensation, such that patient trauma and/or expensive ICU care can be avoided. Although embodiments make specific reference to monitoring electrocardiogram and other physiological signals with an adherent patch, the system methods and devices are applicable to many applications in which physiological monitoring is used, for example wireless physiological monitoring with implanted sensors for extended periods.

Cardiac monitoring and/or stimulation methods and systems that provide one or more of monitoring, diagnosing, defibrillation, and pacing. Cardiac signal separation is employed to detect, monitor, track and/or trend ischemia using cardiac activation sequence information. Ischemia detection may involve sensing composite cardiac signals using implantable electrodes, and performing a signal separation that produces one or more cardiac activation signal vectors associated with one or more cardiac activation sequences. A change in the signal vector may be detected using subsequent separations. The change may be an elevation or depression of the ST segment of a cardiac cycle or other change indicative of myocardial ischemia, myocardial infarction, or other pathological change. The change may be used to predict, quantify, and/or qualify an event such as an arrhythmia, a myocardial infarction, or other pathologic change. Information associated with the vectors may be stored and used to track the vectors.

Apparatus and methods are provided for determining in near realtime the position of a probe placed within a living body. Electric currents are driven between one or more electrodes on the probe and electrodes placed on the body surface. The impedance between the probe and each of the body surface electrodes is measured, and three-dimensional position coordinates of the probe are determined based on the impedance measurements. Dynamic compensation is provided for changing impedance of the body surface and its interface with the electrodes, resulting from such causes as electrode peel-off and changes in moisture and temperature. The compensation improves the accuracy of, inter alia, medical procedures, such as mapping the heart or performing ablation to treat cardiac arrhythmias.

A noninvasive or minimally invasive treatment of cardiac arrhythmia such as supraventricular and ventricular arrhythmias, specifically atrial fibrillation and ventricular tachycardia, by treating the tissue with heat produced by ultrasound, (including High Intensity Focused Ultrasound or HIFU) intended to have a biological and/or therapeutic effect, so as to interrupt or remodel the electrical substrate in the tissue area that supports arrhythmia.

A method and a system for detection of an arrhythmia, the method comprising determining a number of heart beat intervals; determining an instantaneous heart rate for each of the heart beat intervals; determining the variability of the instantaneous heart rates compared to a mean of the number of instantaneous heart rates; determining a non-linear value that represents the variability of the instantaneous heart rates; and detecting the arrhythmia by comparing the non-linear value with a predetermined threshold.

A method is disclosed for displaying patient ECG data. The method includes receiving ECG data including an ECG waveform; receiving analyzed ECG data including arrhythmic events; generating an indicia of the detected arrhythmic event; and displaying the indicia of the detected arrhythmic event in relation to the ECG waveform at a position associated with a time of the detected arrhythmic event. A system for displaying patient ECG data is also disclosed.

A method involves implantably detecting changes in posture of a patient's body. Baroreflex responses to the posture changes are determined. An autonomic tone of the patient is determined based on the baroreflex responses. Based on the autonomic tone, various patient susceptibilities to disease may be determined, including susceptibilities to heart disease, arrhythmia, and/or sudden cardiac death.

The invention provides a disposable sensor patch for the non-invasive detection of heart disease. The patch is placed on a person's chest area for automatic analysis of ECG. The heart condition is indicated via an indicator integrated within the patch. The patch is inexpensive and simple for self-administration. In one embodiment, the status of the heart is indicated via multiple LEDs. The detection and indication typically occurs, within 24 hours or sooner if a condition is readily identifiable. The patch is thin, flexible, and incorporates a battery, ECG amplifier, and a processor for analyzing ECG waveform and indicating the heart condition. A software algorithm searches for a cardiac abnormality such as arrhythmia, bradycardia, tachycardia, fibrillation, mycocardial infarction, ischemia, long-QT syndrome, blocks, late potentials, and premature contractions. In another embodiment, results and relevant ECG data are stored in memory for later retrieval.

Heart treatment equipment and a heart treatment method directed to prevention of a fatal arrhythmia by detecting a physical exercise or a mental stress by using a sensor and thereafter controlling the vagus nerve stimulation, wherein sensor means for detecting various living body information for generating a signal which designates degree of a sympathetic tone is provided and heart rate threshold for carrying out the vagus nerve stimulation is adjusted according to the living body information detected by the sensor means. Further, a nerve stimulation parameter for adjusting the strength of the vagus nerve stimulation is adjusted in response to the degree of the patient sympathetic tone.

An implantable medical device and associated method for automatically generating morphology templates during fast cardiac rhythms, confirming a provisional template as a confirmed template, and using the confirmed template to classify subsequent detected arrhythmias. A provisional SVT template may be created during a fast ventricular rate and activated as a confirmed SVT template upon verification that the fast rate was due to an SVT. The confirmed SVT template may be used to discriminate SVT from VT/VF.

The invention provides a non-invasive method for treatment of arrhythmia. In a first aspect, a method for treatment of atrial fibrillation in a heart of a patient comprises directing radiation from outside the patient toward one or more target treatment regions of the heart so as to inhibit the atrial fibrillation. The radiation may induce isolation of a pulmonary vein.

A method for calculating a variability value that is indicative of AF by obtaining a signal sequence of a plurality of RR intervals by monitoring electrical activity of a patient's heart. Each RR interval is converted into an instantaneous heart rate value and sorted into ascending order. The difference between each successive heart rate is calculated, discarding the two largest differences. The variability value is calculated by adding the retained differences.

An apparatus to detect the onset of sleep apnea, and to provide an automated way to awaken the sleeping patient at the onset of sleep apnea. The apparatus may also contain a recording device or computer that captures blood oxygen levels and pulse rates throughout the period of sleep, and may contain computer programs, algorithms, subroutines or logic to determine the level of blood oxygen and pulse rate that indicates the onset of a sleep apnea event. The method of arousing the patient from sleep at the onset of a sleep apnea event will decrease or eliminate the occurrence of sleep apnea, arrhythmia, and partial epilepsy over time.

A medical device identifies a hemodynamically unstable arrhythmia based upon optical hemodynamic sensor signals. The optical hemodynamic sensor includes a light source for transmitting light corresponding to first and second wavelengths through a blood perfused tissue of a patient and a light detector for generating optical signals corresponding to an intensity of the detected light at the first and second wavelengths. At a low motion period for the patient, optical signals are obtained from the optical hemodynamic sensor and are analyzed to determine a baseline motion level for the patient. Subsequent signals obtained from the optical hemodynamic sensor are compared to the baseline motion levels, with only those signals corresponding to periods where motion does not exceed the baseline level of motion being further analyzed to determine if they are consistent with a hemodynamically unstable arrhythmia.

An arrhythmia discrimination device and method involves receiving electrocardiogram signals and non-electrophysiologic signals at subcutaneous locations. Both the electrocardiogram-signals and non-electrophysiologic signals are used to discriminate between normal sinus rhythm and an arrhythmia. An arrhythmia may be detected using electrocardiogram signals, and verified using the non-electrophysiologic signals. A detection window may be initiated in response to receiving the electrocardiogram signal, and used to determine whether the non-electrophysiologic signal is received at a time falling within the detection window. Heart rates may be computed based on both the electrocardiogram signals and non-electrophysiologic signals. The rates may be used to discriminate between normal sinus rhythm and arrhythmia, and used to determining absence of an arrhythmia.

An implantable medical device and method are provided for assessing autonomic tone and risk factors associated with arrhythmias and, based on this assessment, an early recurrence of ventricular tachycardia or ventricular fibrillation is predicted. Specifically, changes in R—R interval, heart rate variability, patient activity, and myocardial ischemia are measured prior to and after a detected an arrhythmia episode. A recurrence score is calculated as a weighted sum of measured parameters and compared to a prediction criterion. The prediction criterion may be a preset threshold score or an individualized episode template based on previously calculated recurrence scores associated with recurring episodes. Stored parameters and episode-related data may be downloaded for offline analyses for optimizing prediction criteria and monitoring patient status.

A system and method for detecting and classifying cardiac arrhythmias based on cardiac pressure signals or the combination of cardiac electrical and cardiac pressure signals. A cardiac electrogram signal is sensed to derive a cardiac rate from which an arrhythmia detection is made when the cardiac rate meets arrhythmia detection criteria. An intracardiac pressure signal is sensed to derive an indicator of tachycardia based on an analysis of the pressure signal in either the time domain or frequency domain. The detected arrhythmia is classified as tachycardia or fibrillation based on the tachycardia indicator wherein the tachycardia indicator is compared to tachycardia detection criteria and the arrhythmia is classified as tachycardia if tachycardia detection criteria are met and the arrhythmia is classified as fibrillation if the tachycardia detection criteria are not met.

An implantable cardiac stimulation device discriminates and treats accelerated atrial arrhythmias of a patient's heart. The device includes a sensing circuit that senses cardiac activity of one of the patient's atria to provide an atrial activity signal, a detector that detects an accelerated atrial arrhythmia of the patient's heart, and a classifying circuit that measures relative correspondence between successive P waves of the atrial activity signal to classify the detected accelerated atrial arrhythmia as either atrial tachycardia or atrial fibrillation. A therapy circuit provides anti-tachycardia pacing therapy responsive to a classified atrial tachycardia and defibrillation therapy responsive to a classified atrial fibrillation.