60 results about "Av delay" patented technology

Bi-ventricular cardiac pacing systems and systems for improving cardiac function for heart failure patients that pace and sense in right and left ventricles of the heart and particularly pace in one of the right and left ventricles after an AV delay timed from a preceding atrial event and after a spontaneous depolarization in the other of the right and left ventricles to achieve fusion pacing. An A-RVp delay and an A-LVp delay are each determined from an intrinsic sensed A-RVs delay and an intrinsic A-LVs delay. If the derived A-LVp delay becomes substantially equal to or shorter than the intrinsic A-RVs delay, then the A-RVp delay is decremented to be shorter than the A-LVp delay. Bi-ventricular pacing of the RV and LV is then established closely timed to the intrinsic RV and LV depolarizations.

An implantable cardiac stimulating device has a pacing circuit connected via an electrode lead system to a first electrode which stimulates and detects activity in the left ventricle, a second electrode to stimulate and detect activity in the right atrium, and to a third electrode to detect activity in the left atrium. Upon the occurrence of a paced or sensed depolarization of the right atrium, a first AV-delay is started. When the subsequent left atrial depolarization is detected, a new AV-interval is started that is optimized for the left side of the heart. Either the left ventricle only, or both ventricles, is paced at the optimized left side AV-interval.

A medical device for characterizing the cardiac status of a patient equipped with a bi-ventricular pacing active implant device. The implant collects an endocardiac acceleration signal and searches for an optimal pacing configuration. This latter tests a plurality of different pacing configurations and delivers for each tested configuration parameters derived from the endocardiac acceleration peak (PEA). The device derives a patient clinical status from those parameters, the indication being representative of the patient's response to the cardiac resynchronization therapy. Those parameters include: the possibility to automatically get or not a valid optimal AV Delay among all the biventricular pacing configurations; a factor indicating the character sigmoid of the PEA / AVD characteristic; the average value of the PEA for the various configurations; and the PEA signal / noise ratio. The active implantable medical device includes control software and processes for executing the characterizing functionality described.

A pacemaker and a method of employing a pacemaker to pace a patient's heart. The method of operation of the pacemaker includes defining a post ventricular atrial refractory period having a first duration responsive to ventricular events, during which period the pacemaker does not initiate timing of an AV delay responsive to detected atrial depolarizations and in response to events which a may disrupt AV synchrony, such as PVC's, mode changes and the like, defining a post ventricular atrial refractory period having a second duration less than the first duration. The shortened post ventricular atrial refractory period remains in effect only temporarily, for example for one cardiac cycle, and may be initiated on a ventricular event which is the disrupting event or immediately follows the disrupting event, or may be initiated following a later ventricular event.

A cardiac rhythm management device includes a dual chamber pacemaker, especially designed for treating congestive heart failure. The device incorporates a program microcontroller which is operative to adjust the pacing site, AV delay and interventricular delay of the pacemaker so as to achieve optimum hemodynamic performance. Atrial cycle lengths measured during transient (immediate) time intervals following a change in the site, AV delay and interventricular delay are signal processed and a determination can then be made as to which particular configuration yields the optimum performance. Paced transient beats following periods of baseline beats are synchronized to the patient's respiratory cycle to minimize effects of respiratory noise on atrial cycle length measurements.

Herein provided are methods for optimizing the atrio-ventricular (A-V) delay for efficacious delivery of cardiac resynchronization therapy. The A-V delay is set such that pacing-induced left ventricular contraction occurs following completion of left atrial (LA) contraction. This maximizes left ventricular filling (preload) which theoretically results in optimal LV contraction via the Frank-Starling mechanism. In CRT devices, the programmed A-V delay starts with detection of electrical activity in the right atrium (RA). Thus, a major component of the A-V delay is the time required for inter-atrial conduction time (IACT) from the RA to the LA. This IACT can be measured during implantation as the time from the atrial lead stimulation artifact to local electrograms in a coronary sinus (CS) catheter. Assuming that the beginning of LA contraction closely corresponds with the beginning of LA electrical activity, the optimal AV delay should be related to the time between the start of RA electrical activity and the start of LA electrical activity plus the duration of LA atrial contraction. Thus the inventors hypothesized that during atrial pacing the IACT measured at implantation correlated with the echocardiographically defined optimal paced AV delay (PAV).

Methods and systems are provided for determining pacing parameters for an implantable medical device (IMD). The methods and systems provide electrodes in the right atrium (RA), right ventricle (RV) and left ventricle (LV). The methods and systems sense RV cardiac signals and LV cardiac signals at an RV electrode and an LV electrode, respectively, over multiple cardiac cycles, to collect global activation information. The methods and systems identify a T-wave in the LV cardiac signal. The methods and systems calculate a repolarization index based at least in part on a timing of the T-wave identified in the LV cardiac signal. The methods and systems set at least one pacing parameter based on the repolarization index, wherein the at least one pacing parameter that is set represents at least one of an AV delay, an inter-ventricular interval and an intra-ventricular interval. Optionally, the methods and systems may deliver an RV pacing stimulus at the RV electrode such that the LV cardiac signal sensed thereafter includes the RV pacing stimulus followed by a T-wave. The methods and systems determine a waveform metric such as at least one of a QT interval, T-wave duration, and T-wave amplitude, and utilize the waveform metric to determine as the repolarization index.

An implantable cardiac stimulation system capable of automatic capture verification is provided with an associated method for performing automatic testing functions using programmable, or automatically determined, AV delays. Automatic threshold testing and evoked response sensitivity testing performed at a user-specified AV delay setting, rather than a preset setting, allows assessment of automatic capture verification based on an AV delay relevant to daily system function. Further features of the present invention are an adjustable frequency with which automatic threshold tests are performed and an adjustable frequency with which threshold test results are stored in memory in a threshold record for better monitoring of lead stability or impending clinical problems. The frequency of performing threshold tests and the frequency of storing threshold test results may be varied according to the threshold stability. Stored threshold test results are advantageously displayed with respect to a fixed or variable time scale.

Systems and methods for pacing the heart using resynchronization pacing delays that achieve improvement of cardiac function are described. An early activation pacing interval is calculated based on an optimal AV delay and an atrial to early ventricular activation interval between an atrial event and early activation of a ventricular depolarization. The early activation pacing interval for the ventricle is calculated by subtracting the measured AVEA from the calculated optimal AV delay. The early activation pacing interval is initiated responsive to sensing early activation of the ventricle and pacing is delivered relative to expiration of the early activation pacing interval.

A system for monitoring a patient and treating the malfunctioning heart of the patient, either in an automatic mode or in a semiautomatic mode, includes means which derive at least one physiologic signal from or related to the patient's circulatory system representative of hemodynamic status. A feedback loop is implemented in a biventricular implant, in order to automatically or selectively optimize the patient's clinical hemodynamic status. Accordingly, the biventricular implant will be programmed to go through a series of AV delay, RV-LV timing and heart rate sequences which scan a preselected range of programmable values and apply those values to the patient's heart. Hemodynamic patient measurements will be recorded and preferably graphed over those applied values. The optimal AV delay, RV-LV timing sequence and pacing rate can then be selected either manually by a technician, physician or other operator, or automatically via the implant in order to secure the best personalized timing sequence for the patient. Preferably, the implant will also be capable of automatically recording hemodynamic information and adjusting intervals, in order to optimize hemodynamics without third party intervention. Also preferably, the automatic adjusting feature can be selectively programmed on or off using the device programmer, to control manual or automatic intervention.

Methods for optimizing the atrio-ventricular (A-V) delay for efficacious delivery of cardiac resynchronization therapy. In CRT devices, the programmed A-V delay starts with detection of electrical activity in the right atrium (RA). Thus, a major component of the A-V delay is the time required for inter-atrial conduction time (IACT) from the RA to the LA. This IACT can be measured during implantation as the time from the atrial lead stimulation artifact to local electrograms in a coronary sinus (CS) catheter. Assuming that the beginning of LA contraction closely corresponds with the beginning of LA electrical activity, the optimal AV delay should be related to the time between the start of RA electrical activity and the start of LA electrical activity plus the duration of LA atrial contraction. Thus ‘during atrial pacing’ the IACT measured at implantation is correlated with the echocardiographically defined optimal paced AV delay (PAV).

The present invention demonstrates that continuous hemodynamic monitoring can be used to identify the optimal AV-delay in a pacemaker-treated patient with end stage heart failure. The AV-delay determines the timing of late diastolic filling in relation to the onset of ventricular contraction and the duration of diastolic filling. An optimal tuning of the AV-delay improves left ventricular filling pressures in patients with a DDD-programmed pacemaker and is particularly important in the presence of a compromised left ventricular function. It has been discovered that using the lowest ePAD pressure, an indirect parameter of the left ventricular end-diastolic pressure, as an indicator for the optimal AV interval. Importantly, measurements of the ePAD revealed the same optimal AV-delay as echocardiographic assessment of left ventricular diastolic filling by standard echocardiographic methods. Importantly, the HR determined as optimal during the acute hemodynamic test did not turn out to be optimal during daily living activities.

A system including a learning module and an algorithmic module for learning a physiological aspect of a patient body and regulating the delivery of a physiological agent to the body. An embodiment of the invention is an adaptive CRT device performing biventricular pacing in which the AV delay and VV interval parameters are changed dynamically according to the information supplied by the IEGM, hemodynamic sensor and online processed data, in order to achieve optimal hemodynamic performance. A learning module, preferably using artificial neural network, performs the adaptive part of the algorithm supervised by an algorithmic deterministic module, internally or externally from the implanted pacemaker or defibrillator.

A system for monitoring a patient and treating the malfunctioning heart of the patient, either in an automatic mode or in a semiautomatic mode, includes means which derive at least one physiologic signal from or related to the patient's circulatory system representative of hemodynamic status. A feedback loop is implemented in a biventricular implant, in order to automatically or selectively optimize the patient's clinical hemodynamic status. Accordingly, the biventricular implant will be programmed to go through a series of AV delay, RV-LV timing and heart rate sequences which scan a preselected range of programmable values and apply those values to the patient's heart. Hemodynamic patient measurements will be recorded and preferably graphed over those applied values. The optimal AV delay, RV-LV timing sequence and pacing rate can then be selected either manually by a technician, physician or other operator, or automatically via the implant in order to secure the best personalized timing sequence for the patient. Preferably, the implant will also be capable of automatically recording hemodynamic information and adjusting intervals, in order to optimize hemodynamics without third party intervention. Also preferably, the automatic adjusting feature can be selectively programmed on or off using the device programmer, to control manual or automatic intervention.

Heart stimulating system for stimulating at least a ventricle of a heart including: stimulation pulse generator adapted to generate stimulation pulses and connected to a ventricular stimulation electrode for delivering stimulation pulses, atrial sensing stage connected to an electrode for picking up potentials inside an atrium and adapted to sense an excitation or contraction of atrial myocardium, ventricular sensing stage connected to an electrode for picking up potentials inside a ventricle and adapted to sense an excitation or contraction of ventricular myocardium, memory for AV-delay values, a control unit adapted to trigger said stimulation pulse generator to generate ventricular stimulation pulses timed based on AV-delay values stored in said memory and to acquire atrioventricular interval samples, and atrioventricular interval timing analyzing unit for receiving atrioventricular interval samples from said control unit and adapted to generate at least one histogram based on said atrioventricular interval samples and analyze said histograms.

A system and method for an implantable cardiac pacing device provide for delivery of anti-tachycardia pacing of the atrium upon detection of atrial tachycardia combined with automatic re-synchronization of ventricular pacing directly following the last atrial pulse of the anti-tachycardia scheme. At the onset of delivery of the ATP train or like scheme of ATP, an appropriate ventricular pacing interval is calculated to enable asynchronous pacing of the ventricle during the ATP and synchronous delivery of the next ventricular pulse at a delay following the end of the ATP train. Upon determination of AT, an algorithm is used to calculate if a ventricular pacing interval can be found that meets maximum and minimum pacing criteria and also provides that the next ventricular pace pulse following the end of the ATP train will follow the last atrial pulse of the train by a suitable AV delay. If such a suitable pacing interval is found, the ventricular pacing interval is set to a temporary value and the train is delivered. If such a pacing interval cannot be initially determined the system waits for one more atrial sense and then repeats the determination to find such a suitable ventricular pacing interval.

In an implantable medical device that provides atrial and ventricular pacing in an atrial-based pacing mode, longer periods of time are permitted for intrinsic AV conduction to occur. By monitoring the patient's AV delay under these circumstances, useful information is obtained that can be correlated to other patient conditions or symptoms.

An active implantable medical device such as a cardiac prosthesis for the treatment of a heart failure by controlled adjustment of the atrioventricular and interventricular delays. The device provides atrioventricular and / or biventricular stimulation, a sensor delivering at least one hemodynamic parameter correlated with time intervals representative of the succession of the systolic and diastolic phases, and circuits to adjust the AV delay and / or VV delay. The device determines (12) during one cardiac cycle several parameters such as the left ventricular pre-ejection interval LPEI, the left ventricular ejection time LVET, the diastolic filling time FT and the conduction time PR. The device compares (14, 18) these parameters with at least one predetermined criterion. If a condition is met, the device readjusts (16) the AV delay and / or VV delay to maximize the ventricular filling and ejection.

A heart stimulator provides for a more appropriate yet simple setting of the AV-delay. The heart stimulator comprises a stimulation pulse generator adapted to generate electric stimulation pulses and connected to a ventricular stimulation electrode for delivering electric stimulation pulses. A sensing stage connected to an electrode for picking up electric potentials inside a ventricle is adapted to sense an excitation or a contraction of a heart chamber. A memory is adapted to store parameters defining a Bezier function determining the relationship between AV-delay values and heart rate and a control unit connected to said memory, said sensing stage and to said stimulation pulse generator, is adapted to determine an actual AV-delay based on an actual intrinsic heart rate or an actual stimulation rate and a non-linear smoothing interpolation between said parameters stored in said memory.

Embodiments of the present invention provide systems and methods for non-invasive, “in-service” AV delay detection and correction. These systems and methods do not modify the audio signal or the video signal, nor do they rely on any metadata to be carried with the audio signal or the video signal via the distribution path. Instead, agents located at various points along the distribution path generate very small signature curves for the audio signal and the video signal and distribute them to a manager via a separate data path other than the distribution path. The manager calculates a measured AV delay caused by the distribution path based on these signature curves, and then optionally corrects the measured AV delay by adjusting an in-line delay in the distribution path.

An implantable cardiac stimulation device promotes intrinsic activity of a heart during demand pacing. The device increases the time and probability of an AV delay interval extension. The device may further increase the AV delay interval from a first extended AV delay interval to a longer second extended AV delay interval. The device may further encourage intrinsic AV conduction in patients with intact AV conduction by allowing multiple cycles during a search interval and multiple search times to further encourage intrinsic conduction from the atrium to the ventricle.

Methods and systems are described that involve synchronized ventricular pacing that promotes sensing of atrial events. The atrioventricular pacing delay is modified based on characteristics of previously sensed atrial events. The modified AV delay is implemented relative to a first atrial event. A second AV delay is implemented relative to a second atrial event if the second atrial event is sensed during the modified AV delay. A ventricular pacing pulse is delivered following the second AV delay.

Methods and systems are provided for a rate adaptive bi-ventricular fusion pacing. The methods and systems deliver a first pulse at a left ventricular (LV) lead and a second pulse at a right ventricular (RV) lead based on a paced atrio-ventricular (AV) delay. The first pulse timed to be delivered concurrently with an intrinsic ventricular conduction. The methods and systems further repeat the delivery of the first pulse and the second pulse for a predetermined number of cycles. Additionally, the methods and systems measure an intrinsic AV conduction interval, and adjust the paced AV delay based on the intrinsic AV conduction interval and a negative hysteresis delta.