Abstract: Pacing parameters are provided to address cross talk and intrinsic ventricular events occurring within a predefined blanking period following an atrial event. The parameters are used in conjunction with protocol for minimizing or reducing ventricular pacing, wherein ignoring intrinsic ventricular events during the blanking period might otherwise affect the performance of the protocol.

Abstract: A feature named “atrial tracking recovery” (ATR) provides a means of restoring delivery of cardiac pacing therapy upon identification of an AR-VS pattern of cardiac activity. The present invention incorporates a method of monitoring such patterns to determine if they are terminable. Once the AR-VS pattern is identified, according to the present invention the PVARP is shortened to allow sensing of the atrial event, which previously was unable to initiate an SAV interval. Subsequent SAV intervals are shortened until an atrial event is sensed so that a ventricular pacing stimulus is delivered after the SAV interval expires. Since the SAV interval is normally programmed to an interval that is shorter than the intrinsic conduction time, ventricular pacing stimulus is provided after the SAV ends, thereby effectively restoring delivery of a ventricular pacing modality such as cardiac resynchronization therapy (CRT).

Abstract: A system and method is provided for reliably indicating that an implantable medical device is in need of replacement. The system and method measures the operational characteristics of the battery and the operational parameters of the implantable device itself. When these characteristics and parameters reach a defined level, the implantable medical device starts a replacement indicator timer. The replacement indicator timer starts and counts a replacement time period, with the replacement time period ending at a determined replacement date. The determined replacement date is the date at which the implantable medical device should be replaced.

Abstract: A device-implemented software system operates a detection window and adjusts PAV as needed after confirming the presence or detection of evidence of an arrhythmia. The detection window is monitored based on a preferred length. If the detection window is shorter than required, intervals are adjusted for a specific pacing rate. Further, the software system provides means for selecting detection over pacing based on an analysis of a preferred length in the presence of evidence of an arrhythmia.

Abstract: The present invention is directed to the problem of preventing episodes of “AV Desynchronization Arrhythmia” (AVDA), a dual-chamber pacing behavior that is initiated by a PVC or other ventricular event that is not closely preceded by an atrial depolarization event. If the initiating PVC creates retrograde conduction resulting in an atrial refractory-sensed event, and should the succeeding AP fail to capture due to pacing within the atrial refractory period (ARP) a repetitive AVDA sequence (APineffectual-VP-ARrefractory) can persist for an extended period of time and symptoms of pacemaker syndrome can occur. After AVDA detection, the following may occur: delivered atrial pacing (AP) energy may be (dynamically) increased, a atrial pacing (AP) delay interval may be implemented, a mode-switch may be executed, a patient notification process may begin, a histogram may be recorded or processed, and/or a combination thereof may be used in response the detected AVDA sequence.

Abstract: The invention is directed to pacing techniques designed to avoid competitive atrial pacing. In particular, the techniques dynamically adjust a non-competitive atrial pacing (NCAP) interval based on sensed cardiac conditions. An apparatus capable of delivering pacing stimuli, such as a pacemaker or an implantable cardioverter/defibrillator (ICD), is described that inhibits delivery of an atrial pacing stimulus for an NCAP interval having a duration that is adjusted according to sensed cardiac conditions. The apparatus may adjust the duration of the NCAP interval when sensing, for example, premature ventricular contraction (PVC), pacemaker mediated tachycardia (PMT), or atrial arrhythmia (AA).

Abstract: A device is provided, the device comprising an implantable medical device and a controller controlling the implantable medical device, the controller having a plurality of modular features and having a firmware architecture allowing modular feature design and implementation, the firmware architecture coordinating between and among the plurality of modular features to reduce feature-to-feature interactions. The device also comprises the controller having a converter enabling efficient conversion between at least one identifiable first modular feature working in a rate domain and at least one identifiable second modular feature working in an interval domain.

Abstract: A device-implemented software system operates a detection window and adjusts PAV as needed after confirming the presence or detection of evidence of an arrhythmia. The detection window is monitored based on a preferred length. If the detection window is shorter than required, intervals are adjusted for a specific pacing rate. Further, the software system provides means for selecting detection over pacing based on an analysis of a preferred length in the presence of evidence of an arrhythmia.

Abstract: The invention is directed to pacing techniques designed to avoid competitive atrial pacing. In particular, the techniques dynamically adjust a non-competitive atrial pacing (NCAP) interval based on sensed cardiac conditions. An apparatus capable of delivering pacing stimuli, such as a pacemaker or an implantable cardioverter/defibrillator (ICD), is described that inhibits delivery of an atrial pacing stimulus for an NCAP interval having a duration that is adjusted according to sensed cardiac conditions. The apparatus may adjust the duration of the NCAP interval when sensing, for example, premature ventricular contraction (PVC), pacemaker mediated tachycardia (PMT), or atrial arrhythmia (AA).

Abstract: A device is provided, the device comprising an implantable medical device and a controller controlling the implantable medical device, the controller having a plurality of modular features and having a firmware architecture allowing modular feature design and implementation, the firmware architecture coordinating between and among the plurality of modular features to reduce feature-to-feature interactions. The device also comprises the controller having a converter enabling efficient conversion between at least one identifiable first modular feature working in a rate domain and at least one identifiable second modular feature working in an interval domain.

Abstract: Multi-site cardiac pacing systems for providing pacing to multiple sites in a patient's heart, e.g., in a single heart chamber or in right and left heart chambers, while avoiding inappropriate responses to double sensing of an evoked depolarization conducted between the sites. A conditional refractory period and further post-event time periods, e.g. a conventional refractory period, are started upon a sense event or pacing pulse sensed at or delivered to a first pace/sense site. A sense event detected at another sense site that occurs during the conditional refractory period is characterized as a conditional refractory event, and it restarts shortened post-event time periods and terminates the conditional refractory period. The restarted post-event time periods are reduced in length by the elapsed time between the starting and termination of the conditional refractory period.

Abstract: A pacing system provided with a mode switching feature and ventricular rate regularization (VRR) function adapted to stabilize or regularize ventricular heart rate during chronic or paroxysmal atrial tachyarrhythmia. In a preferred embodiment, the pacing system nominally operates in an atrial synchronized pacing mode such as DDD or DDDR pacing mode. In response to detection of atrial rhythm characteristics consistent with an atrial tachyarrhythmia, e.g., atrial fibrillation, a mode switch into a non-atrial synchronized, ventricular rate regularization pacing mode, e.g. DDIR or VDIR pacing mode, is made. If the VRR function is programmed on, the ventricular pacing rate based upon a rate responsive sensor derived ventricular pacing rate modulated on a beat by beat basis by preceding intrinsic or paced ventricular events, the stability of the intrinsic ventricular heart rate, and any atrial pace events to regularize the ventricular pacing rate.

Abstract: 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.

Abstract: Because a determination of atrial tachycardia can occur too often where the pacemaker maintained true atrial interval value is designed to converge on the shortest A-A intervals, a method and apparatus either extends PVAB to cover inappropriate atrial senses that should not be counted in determining the true atrial interval, primarily where they occur after an atrial pace, or removes other AS events from consideration.

Abstract: A dual chamber pacemaker is provided, preferably either DDDR or DDIR, having logic hardware and/or software for normally carrying out the DDIR or DDDR mode of operation, and further having means for carrying out a safe atrial pace method of operation in circumstances where normal atrial pacing could otherwise be competitive or result in loss of atrial capture. The pacemaker has means for detecting an atrial sense during PVARP, timing out a delay from the time of the early atrial sense, delivering a safe atrial pulse at the end of the delay, and controlling generation of a ventricular pace pulse in synchronous relation to the safe atrial pulse and with at least a minimum AV interval.

Abstract: An improved atrial synchronous dual-chamber pacemaker provided with a variable refractory period during which the pacemaker is not responsive to sensed atrial contractions. The atrial refractory period is selected based upon whether the ventricular pacing pulse preceding the refractory occurred as a result of time out of the interval corresponding to the basic ventricular pacing rate, or due to time out of the A-V delay interval initiated in response to sensing of a natural atrial contraction. The pacemaker may most easily be practiced by modifying a DDD type pacemaker, and employing the V-A interval, normally separating an atrial pacing pulse from an immediately preceding ventricular contraction, as an extended atrial refractory period, employed only after generation of a ventricular pacing pulse not triggered by a preceding atrial contraction.

Abstract: A switched capacitor ventricular sense amplifier for an implantable pulse generator having unique control of the switching clock for minimization of transients during the period just preceding, during and following an atrial paced event. The timing is modified to discontinue switching during this period. This ensures that transients occurring as a result of functionally disconnecting and subsequently reconnecting the sensing lead with the sense amplifier are not propagated within the switched capacitor bandpass filter. An alternative approach is to increase the clocking rate during the blanked period to ensure that the transients created by the atrial pace or by disconnecting and reconnecting the sensing lead are rapidly processed by the switched capacitor bandpass filter and that processing is completed shortly following the atrial paced event. This alternative approach requires a gate at the sense amplifier output to disable propagation of any transients processed.

Abstract: A cardiac pacemaker system of the type including a sensor responsive to the metabolic demand for oxygen and which varies the pacing rate in response to the output of the sensor. The pacemaker defines a function relating sensor output to pacing rate, based upon independently selectable parameters, including a first rate which may be the lower rate of the pacemaker, a second rate which may also be the upper rate of the pacemaker, and a predetermined activity level. The function defined by the pacemaker varies the pacing rate between the first and second rates, with the second rate being achieved at the selected sensor output. The pacemaker system provides both simplicity and extraordinary flexibility, allowing rate responses to be optimized to the needs of a individual patients.

Abstract: Two pairs of solid state current path means, disclosed as transistors, are interconnected to provide an accurate dead band control circuit means. The transistors have emitters that are intentionally mismatched in size thereby creating dissimilar current conducting characteristics for each pair of transistors. The switching characteristics of each pair of transistors can be controlled by the areas of the emitters and thereby a dead band can be created between the two pairs of transistors which can be used as an accurate dead band control.