摘要:
Programmable timing and logic circuitry is provided to detect crosstalk between paced chambers of the heart and to provide compensation in the event crosstalk is detected. Signals sensed during a prescribed time window early in the cardiac cycle following an atrial pulse are presumed to be crosstalk. If crosstalk occurs, a shortened AV delay is triggered. If crosstalk does not occur, a programmed AV delay is maintained. Absent the occurrence of a ventricular event after the prescribed time window up to the end of the AV delay, a ventricular stimulation pulse is provided. If a ventricular event is sensed during this time, the ventricular stimulation pulse is inhibited.
摘要:
Embodiments include a cardiac rhythm management system having a lead that includes an omni-directional pressure sensor that is configured to resist tissue in-growth and provide reliable and consistent pressure readings from within a patient's vasculature. Embodiments of the cardiac rhythm management lead may also include a variety of pacing and shocking electrodes.
摘要:
A system for detecting and treating congestive heart failure includes an implantable module, such as a pacemaker, and a patient advisory module. The system is configured to measure thoracic impedance and to provide the patient with instructions in order to improve the accuracy of the thoracic impedance measurement as well as treating symptoms of congestive heart failure.
摘要:
An implantable cardiac stimulation device applies pacing stimulation pulses to a heart and senses evoked responses to the pacing stimulation pulses. A pulse generator applies the stimulation pacing pulses to the heart in accordance with a pacing configuration. A sensor control selects an evoked response sensing electrode configuration from among a plurality of evoked response sensing electrode configurations in response to the pacing configuration. A sensor is then programmed to sense the evoked responses with the selected evoked response sensing electrode configuration. In accordance with a preferred embodiment, signal-to-noise ratios obtained with the various electrode configurations are used to select a best electrode configuration for sensing evoked responses.
摘要:
A pacemaker programmer and diagnostic system retrieves information stored within a pacemaker and analyzes the retrieved data in real time. The stored information can be retrieved by a telemetry communication link. The programmer includes features for allowing the physician to interactively adjust program parameters while viewing the results of parameter changes in real-time. The programmer performs a ventricular sensitivity threshold test by setting the stimulation device to an atrial tracking mode, and by assessing the ventricular sensing of the pacemaker. If ventricular sensing is confirmed, the processor performs a ventricular sensitivity threshold test to determine the pacemaker ventricular sensitivity threshold, and then automatically adjusts the ventricular sensitivity to within a safety margin from the ventricular sensitivity threshold. The programmer also performs an atrial sensitivity threshold test by setting the stimulation device to the atrial tracking mode, and by assessing the atrial sensing of the pacemaker. If atrial sensing is confirmed, the programmer determines whether the base rate is less than the sensed atrial rate by 20 BPM or more; if so, the processor performs an atrial sensitivity threshold test to determine the pacemaker atrial sensitivity threshold, and automatically adjusts the atrial sensitivity to within a safety margin from the atrial sensitivity threshold.
摘要:
An implantable pacemaker accurately senses the regular atrial rhythm even though some portions of the atrial rhythm, e.g., every other P-wave, may potentially be masked or hidden within the ventricular absolute refractory period. Such sensing includes unmasking or uncovering any hidden P-waves, thereby allowing an accurate atrial rate to be determined. The hidden P-waves are uncovered by: changing the PV delay, not tracking a sensed P-wave, or comparing the incoming morphology of the atrial channel signal to a prior stored baseline morphology signal. The accurate atrial rate, once determined, allows the presence of an atrial tachycardia to be reliably confirmed, thereby enabling appropriate atrial anti-tachycardia pacing (ATP) procedures to be invoked, or mode switching from an atrial synchronous mode of operation, e.g., DDD, to a non-atrial synchronous mode, e.g., VVIR.
摘要:
An implantable pacemaker operates in a DDD mode and reverts to a modified DDI mode in response to sensing atrial depolarization early in the pacing cycle. The modified DDI mode, when invoked, provides additional atrial kick by generating an atrial stimulation pulse (A-pulse) when there is sufficient time left in the current pacing cycle for the atrial kick resulting from such A-pulse to be of hemodynamic and electrophysiologic benefit. A time window, T.sub.A, is defined that follows the post-ventricular atrial refractory period (PVARP) of the normal DDD pacing cycle. If a P-wave is sensed during T.sub.A, then the modified DDI mode is invoked. In such modified DDI mode, the time between the last ventricular event and the next scheduled V-pulse, absent the detection of an inhibiting R-wave, is preserved. Further, in such modified DDI mode, if there is sufficient time to supply an A-pulse before the next V-pulse is scheduled, such A-pulse will be generated to provide the additional atrial kick. In one embodiment, if there is more than a fixed time interval e.g., 300 msec, plus a programmed AV delay (AVD) time remaining before the next scheduled V-pulse after sensing a P-wave during the time window T.sub.A, then an A-pulse is generated one AVD time prior to the next scheduled V-pulse.
摘要:
An implantable pacemaker continuously records pacing events and their respective rates of occurrence in sequence, as they occur, into an Event Record stored in a circular buffer. The circular buffer always contains the most recent events and rates collected. The recording of the pacing events selectively occurs at every event, or at sampling rates of one event per fixed sample interval. A programming device, coupled to the implantable pacemaker through a telemetry link, selectively retrieves the recorded pacing events and rates from the Event Record and reports subsets thereof in condensed or summarized form using numerical and/or graphical formats. The pacing event data collected in the Event Record is three-dimensional in that each pacing event includes a pacemaker event, an associated pacemaker or heart rate, and a real time interval. The programming device also calculates and reports statistical information from the data collected in the Event Record. The Event Record provides a base recording that establishes the behavior of the pacemaker in a particular patient under ascertainable conditions.
摘要:
A system within an implantable stimulation device and a method for limiting the extent to which rate-responsiveness can be utilized during low battery periods. A battery threshold detector is utilized to detect when the battery is below a predetermined threshold. The implantable stimulation device then switches to base rate, but with a preset recovery time used to prevent rapid rate change. In an alternate embodiment, the device may then become rate-responsive again, but with a lower allowable maximum sensor rate being used.
摘要:
A system within an implantable stimulation device and a method for limiting the extent to which any high power consumption modes, such as a rate response mode, can be utilized during low battery periods. A battery threshold detector is utilized to detect when the battery is below a predetermined threshold. The implantable stimulation device then switches from a high current drain mode of operation to progressively lower current drain modes of operation. This configuration allows a significant reduction in current drain at RRT and further prevents the output amplitude from dropping below the capture level and prevents the remaining battery capacity from being rapidly used up.