56 results about "Ventricular depolarization" patented technology

An implantable medical device operates to promote intrinsic ventricular depolarization according to a pacing protocol. The medical device monitors the AV interval and adjusts the Ventricular Pacing Protocol if the AV interval exceeds a threshold when the cardiac rate is elevated.

An apparatus and method for delivering electrical shock therapy in order to treat atrial tachyarrhythmias such as fibrillation in which the energy stored in a capacitor used to deliver a shock pulse is monitored and adjusted. A charging circuit is used to charge the capacitor from a supply voltage upon detection of an atrial arrhythmia, and a controller monitors sensed ventricular depolarizations until R-wave synchrony requirements are met so that an atrial shock pulse can be safely delivered. The controller also attempts to maintain the voltage of the capacitor at a specified voltage before delivery of the shock pulse by operation of the charging circuit.

A method of analyzing physiological data indicative of myocardial activity is disclosed. The method comprises: identifying in the data a set of N features, each corresponding to a ventricular depolarization, and calculating M time-intervals for each ventricular depolarization feature, thereby providing a vector of N*M time-intervals. The method further comprises fitting the vector to a power density function of time-intervals, and determining possible cardiac arrhythmia based on statistical parameters characterizing the function.

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, operatively connectable both to a cardiac-rhythm-management (CRM) subject, and to a CRM device associated with that subject, and an associated method, operable, in relation to received-and-processed, real-time, CRM-subject-specific, simultaneous ECG and heart-sound information, and other information including measurement time markers where available, for blocking, under all circumstances during the ventricular relative refractory period lying within each of successive CRM-subject cardiac cycles occupying a span of such cycles, the ventricular pacing activity of the subject-associated CRM device—the beginning and ending of such blocking in each cardiac cycle being system-defined to lie preferably, and respectively, (a) within the real-time, ventricular depolarization window in the cycle, and (b) at the time of the real-time, S2 heart-sound, plus or minus any user-defined time-delta.

An implantable cardioverter defibrillator (ICD) senses ventricular depolarizations (R-waves) in an electrogram signal to detect a ventricular tachycardia or fibrillation episodes. The EGM signal is also monitored in real time for characteristics that uniquely identify instances of T-wave oversensing. The ICD determines whether detection of a tachycardia or fibrillation episode is appropriate based upon counts of each of the unique characteristics evidencing T-wave oversensing.

An apparatus and method for delivering electrical shock therapy in order to treat atrial tachyarrhythmias such as fibrillation in which the energy stored in a capacitor used to deliver a shock pulse is monitored and adjusted. A charging circuit is used to charge the capacitor from a supply voltage upon detection of an atrial arrhythmia, and a controller monitors sensed ventricular depolarizations until R-wave synchrony requirements are met so that an atrial shock pulse can be safely delivered. The controller also attempts to maintain the voltage of the capacitor at a specified voltage before delivery of the shock pulse by operation of the charging circuit.

A pacemaker having a hysteresis feature which permits intrinsic heart activity, controlled by the sinus node to resume optimally after pacing. The pacemaker has a programmable lower rate and upper rate, a programmable lower hysteresis rate (LRH) corresponding to a lower rate hysteresis interval (LRHI), and a programmable rate (IR) intermediate an upper pacing rate (UR) and a lower pacing rate (LR). A microprocessor measures the average rate of change MAVG in the intervals between consecutive ventricular depolarizations, and compares the last intrinsic escape interval RRN to the lower rate hysteresis interval (LRHI).If the last intrinsic escape interval RRN is longer than the lower rate hysteresis interval (LRHI), and if the value of MAVG is greater than a first preselected value SL1 but less than a second preselected value SL2, the pacemaker stimulates at the lower rate hysteresis (LRH) and thereafter gradually increases the pacing rate up to the intermediate rate (IR). A time counter maintains a continuous pacing at the intermediate rate (IR) for a predefined period of time, and the pacing rate is gradually decreased toward the lower pacing rate (LR).

A method and apparatus for reducing a patient's heart rate or blood pressure. The apparatus provides stimulation to the patient's atrial and / or nodal tissue within the associated refractory period of the ventricle but outside of an associated refractory period of the stimulated atrial an / or nodal tissue, responsive to detecting an occurrence of a ventricular depolarization following a preceding atrial depolarization.The apparatus may define a time window following the ventricular depolarization, following the atrial depolarization or determined based upon the timing of both the atrial and ventricular depolarizations. The stimulus may be delivered during or on expiration of the defined time window. The duration of the time window may be pre-set or determined based upon measurements of the patient's refractory periods.

An implantable medical device operates to promote intrinsic ventricular depolarization according to a pacing protocol. The medical device operates to promote intrinsic conduction by providing elongated AV intervals or operating in an atrial based pacing mode. Conduction checks to determine if AV conduction is present are performed on a graduated or progressive scale to facilitate intrinsic emergence.

An apparatus includes a sensing circuit configured to generate a sensed physiological signal representative of cardiac activity of a subject, and an arrhythmia detection circuit. The arrhythmia detection circuit is configured to monitor information corresponding to ventricular depolarization (V-V) intervals using the sensed physiological signal; determine a V-V interval distribution; determine a heart rate density index (HRDI) as a portion of samples of the V-V interval distribution corresponding to a V-V interval occurring most often in the distribution; and generate an indication of atrial fibrillation (AF) using the HRDI.

In some embodiments, a method for operating a cardiac rhythm management device may include one or more of the following steps: (a) sensing atrial depolarizations through an implanted atrial electrode, (b) administering a sequential CRT pacing therapy in a sequential CRT pacing mode to a left and right ventricle of a heart of a patient via implanted ventricular electrodes in a sequential bi-ventricular fashion, (c) switching from the sequential CRT pacing mode to a simultaneous CRT pacing mode, (d) administering a simultaneous CRT pacing therapy in the simultaneous CRT pacing mode to the left and right ventricle in a simultaneous bi-ventricular fashion, (e) analyzing the sensed atrial depolarizations to detect the presence of an atrial arrhythmia, (f) analyzing the sensed atrial depolarizations while in the sequential CRT pacing mode to detect the presence of atrial arrhythmia, and (g) sensing ventricular depolarizations of the left and the right ventricle.

An implantable medical device operates to promote intrinsic ventricular depolarization according to a pacing protocol. The medical device monitors the number of attempts made to promote intrinsic conduction in comparison with the number of successful cardiac cycles to determine an efficiency value.

A method implemented in a dual chamber cardiac rhythm management device for identifying non-sinus ventricular depolarizations following an atrial event. The PR interval for a sensed ventricular beat that occurs after either an atrial pace or an atrial sensed event is examined and if it falls into a non-physiologic range, it is classified as an ectopic beat. If the PR interval is close to a physiologic range, the RR to AA ratio and a PR interval for the current beat are compared to those for an immediately preceding beat. Attention is also paid to the morphology of the ventricular depolarization in determining whether a beat is ectopic or not.

Cardiac catheterization is carried out using a probe having sensing electrodes disposed on a distal portion thereof, placing the sensing electrodes in galvanic contact with respective locations in an atrium of the heart, thereafter acquiring electrograms from the sensing electrodes while concurrently detecting ventricular depolarization events, generating from the electrograms a time-varying electroanatomic map showing electrical propagation in the heart, and displaying the electroanatomic map in a series of visual images, the images including an icon that visually indicates the ventricular depolarization events.

An implantable medical device operates to promote intrinsic ventricular depolarization according to a pacing protocol. The medical device determines a course of action based upon the presence or absence of sensed ventricular activity. The device further determines whether that activity is properly conducted or the result of a PVC or nodal rhythm.

Cardiac catheterization is carried out using a probe having sensing electrodes disposed on a distal portion thereof, placing the sensing electrodes in galvanic contact with respective locations in an atrium of the heart, thereafter acquiring electrograms from the sensing electrodes while concurrently detecting ventricular depolarization events, generating from the electrograms a time-varying electroanatomic map showing electrical propagation in the heart, and displaying the electroanatomic map in a series of visual images, the images including an icon that visually indicates the ventricular depolarization events.