Abstract: A maximum pacing rate limiter for use in adaptive rate pacing in conjunction with a cardiac rhythm management system for a heart. The maximum pacing rate limiter may function to measure an interval, termed the ERT interval, between a paced ventricular evoked response and a T-wave. The maximum pacing rate limiter may further function to maintain the ERT interval at less than a certain percentage of the total cardiac cycle. In one disclosed embodiment, a maximum pacing rate limiter calculates an ERT rate based on the detected paced ventricular evoked response and the T-wave, and the pacing rate limiter module further communicates the minimum of the ERT rate and an adaptive-rate sensor indicated rate to a pacemaker.

Abstract: A plurality of chronic sensors are used to facilitate diagnosis and medical decision making for an individual patient. An expert system evaluates the sensor data, combines the sensor data with stored probability data and provides an output signal for notification or medical intervention.

Abstract: A cardiac rhythm management system includes a heart sound detector providing for detection of the third heart sounds (S3). An implantable sensor such as an accelerometer or a microphone senses an acoustic signal indicative heart sounds including the second heart sounds (S2) and S3. The heart sound detector detects occurrences of S2 and starts S3 detection windows each after a predetermined delay after a detected occurrence of S2. The occurrences of S3 are then detected from the acoustic signal within the S3 detection windows.

Abstract: A cardiac rhythm management system provides for the trending of a third heart sound (S3) index. The S3 index is a ratio, or an estimate of the ratio, of the number of S3 beats to the number of all heart beats, where the S3 beats are each a heart beat during which an occurrence of S3 is detected. An implantable sensor such as an accelerometer or a microphone senses an acoustic signal indicative heart sounds including S3. An S3 detector detects occurrences of S3 from the acoustic signal. A heart sound processing system trends the S3 index on a periodic basis to allow continuous monitoring of the S3 activity level, which is indicative of conditions related to heart failure.

Abstract: An implantable device monitors the balance between sympathetic tone and parasympathetic tone as a function of an activity level. Cardio-neurological healthy users exhibit a generally sympathetic tone in conjunction with heavy activity level and a generally parasympathetic tone in conjunction with periods of low activity level. Deviations from expected results are associated with a health problem. Measured conditions are stored and available for subsequent reporting to a remote programmer. Therapy delivered by an implantable device is determined as a function of the relationship between autonomic balance and activity level.

Abstract: A guiding catheter for use in medical procedures includes a flexible shaft with one or more audio transducers and a distal tip. An audio signal may be sent to one or more of the transducers and a reflected signal is received at one or more transducers. The reflected signal is used to detect the presence of an anatomical structure to assist in navigating the catheter to its destination. In another arrangement, the transducer can be used passively to detect physical characteristics of the heart such as sound, subsonic energy or temperature, that indicate relative proximity of a destination vessel.

Abstract: A cardiac rhythm management system measures a time interval between a first fiducial marker indicative of a ventricular depolarization (e.g., a Q-wave, an R-wave, etc.) and a second fiducial marker indicative of a subsequent mitral valve closure (MVC) occurring during the same cardiac cycle. Such time intervals are used for detecting atrioventricular (AV) dissociation. The AV dissociation may, in turn, be used for discriminating between a supraventricular tachyarrhythmia (SVT) and a ventricular tachyarrhythmia (VT) or for any other diagnostic or therapeutic purpose. The AV dissociation and/or SVT/VT discrimination information may be communicated from an implantable cardiac rhythm management device to an external interface and/or used to determine the nature of therapy delivered to the subject. In a further example, amplitudes indicative of the MVCs are also used for determining whether AV dissociation exists.