Abstract: A cardiac rhythm management system having a plurality of timers and programming adapted to receive a status array. The status array is based on the status of each timer of the plurality of timers and includes intrinsic activity detection for each pace sense site. The plurality of timers are initiated concurrent with a detected event or condition. The status array is masked according to an enable array and an interrupt signal is generated based on selected bit transitions of the status array. The interrupt signal initiates a predetermined therapy or function based on the status array. A FIFO buffer preserves the order of senses and paces for further processing. The predetermined therapy or function includes determining a mode of operation of the system.

Abstract: An implantable medical tissue stimulating device is designed to capture fault history relating to error events in a manner that allows subsequent analysis of operational performance prior to, during and subsequent to the occurrence of a detected error. Physiologic and operational data are fed through a buffer capable of temporarily storing such data over a predetermined interval. When a fault condition is detected, a trigger signal is generated a predetermined time following the occurrence of the fault condition and, upon generation of the trigger signal, the contents of the buffer are stored away in a RAM memory for subsequent read-out.

Abstract: A cardiac rhythm management system recognizes patterns of interval durations, distinguishing between events in different heart chambers even though signals associated with those different heart chambers are processed using a commonly shared sensing circuit. A therapy delivery algorithm ignores intervals between cardiac events occurring in different heart chambers when determining a cardiac rate upon which the delivery of therapy is based. This reduces the risk of inappropriate delivery of therapy to the patient. Delayed conduction left ventricular beats are not erroneously recognized as a subsequent right ventricular beat, preventing such short intervals from inappropriately triggering a defibrillation countershock. The system detects cardiac events, obtains a current interval between a current cardiac event and a previous cardiac event, and classifies the current interval into at least first and second categories, based on a duration of the current interval.

Abstract: A cardiac rhythm management system recognizes patterns of interval durations, distinguishing between events in different heart chambers even though signals associated with those different heart chambers are processed using a commonly shared sensing circuit. A therapy delivery algorithm ignores intervals between cardiac events occurring in different heart chambers when determining a cardiac rate upon which the delivery of therapy is based. This reduces the risk of inappropriate delivery of therapy to the patient. Delayed conduction left ventricular beats are not erroneously recognized as a subsequent right ventricular beat, preventing such short intervals from inappropriately triggering a defibrillation countershock. The system detects cardiac events, obtains a current interval between a current cardiac event and a previous cardiac event, and classifies the current interval into at least first and second categories, based on a duration of the current interval.

Abstract: Recognizing that delivery of pacing therapy to a patient may increase the risk of inappropriate delivery of anti-tachyarrhythmia therapy, a modified atrial-based timing device and method delivers pacing and anti-tachyarrhythmia therapy to the patient such that the risk is reduced. A ventricular-atrial (VA) time interval is increased, when an intrinsic ventricular activation is sensed during an atrial-ventricular (AV) time interval, by the time remaining in the immediately preceding AV time interval following the intrinsic ventricular activation sensed therein. As a result, the patient's heart rate is not elevated, in response to ventricular activations sensed during the AV time interval, and a tachyarrhythmia rate threshold is not exceeded, thereby avoiding inappropriate delivery of anti-tachyarrhythmia therapy.

Abstract: An implantable cardiac stimulator having a bradycardia pacer and a defibrillator in a common housing and sharing common atrial and ventricular sense circuits includes circuitry for defining a dynamic paced refractory interval that is inversely proportional to the pacing rate to thereby allow adequate time in the cardiac cycle for sensing ventricular events even at elevated pacing rates such as when the atrial tracking rate approaches a programmed upper rate limit for the pacemaker or a sensor driven rate approaches the programmed upper rate limit.