Abstract: An implantable medical device is provided that comprises a housing, sensors configured to be located to proximate a heart, and a sensing module to sense cardiac signals originating from the heart over a channel defined by the sensors. The cardiac signals include intrinsic R-wave events and associated intrinsic confirmation events when the heart exhibits normal sinus rhythm. The device further includes memory to store the cardiac signals sensed over a channel, and a detection module. The detection module identifies an R-wave event within the cardiac signals. The detection module captures, in the memory, a segment of the cardiac signals that precedes the R-wave event as a retrospective segment. The detection module determines whether the retrospective segment includes an intrinsic confirmation event that is associated with and occurs before the R-wave event.

Abstract: A surface electrocardiogram (EKG) is emulated using signals detected by internal leads of an implanted device. In one example, emulation is performed using a technique that concatenates portions of signals sensed using different electrodes, such as by combining far-field ventricular signals sensed in the atria with far-field atrial signals sensed in the ventricles. In another example, emulation is performed using a technique that selectively amplifies or attenuates portions of a single signal, such as by attenuating near-field portions of an atrial unipolar signal relative to far-field portions of the same signal. The surface EKG emulation may be performed by the implanted device itself or by an external programmer based on cardiac signals transmitted thereto. A transtelephonic monitoring network is also described, wherein the emulated surface EKG (or raw data used to emulate the EKG) is relayed from an implanted device to a remote monitor, typically installed in a physician's office.

Abstract: Techniques are provided for use by implantable medical devices such as pacemakers or by external systems in communication with such devices. An intracardiac electrogram (IEGM) is sensed within a patient in which the device is implanted using a cardiac signal sensing system. Cardiac events of interest such as arrhythmias, premature atrial contractions (PACs), premature ventricular contractions (PVCs) and pacemaker mediated tachycardias (PMTs) are detected within the patient using event detection systems and then portions of the IEGM representative of the events of interest are recorded in device memory. Subsequently, during an off-line or background analysis, the recorded IEGM data is retrieved and analyzed to identify false detections. In response to false detections, the cardiac signal sensing systems and/or the event detection systems of the implantable device are selectively adjusted or reprogrammed to reduce or eliminate any further false detections, including false-positives or false-negatives.

Abstract: A method and system are provided for trending variation in coronary burden across multiple heart rate ranges. The method and system include obtaining cardiac signals having a segment of interest over a period of time where each cardiac signal has an associated heart rate that falls within at least one heart rate range. Segment variations of the segment of interest are determined and grouped based on the associated heart rates to produce distributions of segment variations that are associated with the heart rate ranges. Trending information is produced by automatically comparing the distributions of segment variations between different heart rate ranges.

Abstract: An implantable medical device includes a lead, a pulse generator, an autothreshold module and a control module. The lead includes electrodes positioned within a heart. At least one of the electrodes senses cardiac signals. The pulse generator delivers a stimulus pulse through at least one of the electrodes. The autothreshold module performs a threshold search when operating in an autothreshold mode and causes atrial stimulus pulses to be delivered in an atrium of the heart at an overdrive rate during the threshold search. The control module determines an AV conduction time and applies an overdrive AV adjustment to the AV conduction time to generate an AV delay. The autothreshold module uses the AV delay in connection with delivering ventricular stimulus pulses to a ventricle of the heart.

Abstract: An implantable medical device includes a lead, a pulse generator, an autocapture module, an autothreshold module, a fusion detection module, and a control module. The lead includes electrodes configured to be positioned within a heart. At least one of the electrodes is capable of sensing cardiac signals. The pulse generator delivers a stimulus pulse through at least one of the electrodes. The autocapture module senses an evoked response of the heart after delivery of the stimulus pulse when operating in an autocapture mode. The autothreshold module performs a threshold search when operating in an autothreshold mode. The fusion detection module identifies fusion-based behavior in the heart. The control module automatically switches between the autothreshold and autocapture modes based on a presence of the fusion-based behavior.

Abstract: A system and method provide precise detection of the time of occurrence of a cardiac event of a heart. The method comprises the steps of sensing electrical activity of the heart to generate an electrogram of the heart and applying the electrogram to an event detector having a plurality of spaced apart thresholds. The thresholds are selected such that the electrogram has an amplitude for crossing at least one of the thresholds. The method further comprises determining a characteristic identifying feature of the electrogram at each threshold crossing of the electrogram, comparing the determined characteristic identifying features to an electrogram template, and identifying the time of occurrence of the cardiac event based upon the comparison.

Abstract: A system and method enables precise detection of the time of occurrence of a cardiac event of a heart. The method includes the steps of sensing electrical activity of the heart to generate an electrogram signal including the cardiac event, storing the electrogram signal, correlating the electrogram signal with an electrogram template, and identifying the time of occurrence of the cardiac event based upon the correlation.

Abstract: Cardiac pacing may be controlled through retrospective detection of events that are sensed during a given period of time. In some embodiments a detection decision is made substantially prior to the end of an escape interval. In some embodiments the mode of detection may be changed near the end of the period of time. In some embodiments the period of time is extended when an event is detected near the end of the period of time.

Abstract: An exemplary method includes performing a ventricular capture assessment, determining a ventricular paced propagation delay (PPD) and/or an interventricular conduction delay (IVCD) using information acquired during the ventricular capture assessment and optimizing at least an interventricular delay (VV) based at least in part on the ventricular paced propagation delay (PPD) and/or the interventricular conduction delay (IVCD). Another exemplary method includes performing an atrial capture assessment, determining an atrial evoked response width (?A) and one or more atrio-ventricular intervals (AR) using information acquired during the atrial capture assessment and optimizing an atrio-ventricular (PV or AV) delay based at least in part on the atrial evoked response width (?A) and the one or more atrio-ventricular intervals (AR). Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: A plurality of electrodes are implanted in, on or near the patient's heart and initially configured to define first circuits or vectors enabled for at least one of sensing and stimulating and second circuits or vectors which are idle for at least one of sensing and stimulating. Selected first circuits or second circuits are tested for fault indications related to one or both of sensing and stimulating and a status record is updated to indicate corresponding sensing fault indications and stimulating fault indications. If a sensing fault is found in one of the first circuits, the first circuit is redefined when enabled for sensing to include at least one electrode of a second circuit that does not have a record of a sensing fault indication. Likewise, if a stimulating fault is found in one of the first circuits, the first circuit is redefined when enabled for stimulating to include at least one electrode of a second circuit that does not have a record of a stimulating fault indication.

Abstract: A cardiac capture threshold may be determined using a test pulse and a backup pulse. Here, delivery of a test pulse is followed almost immediately by a non-conditional backup pulse of sufficient energy such that the backup pulse should always capture in the event the test pulse does not capture. The timing of the evoked response that follows the backup pulse may then be used to determine whether the test pulse or the backup pulse captured the cardiac tissue. In some embodiments morphology discrimination may be employed to determine whether an evoked response was triggered by the test pulse or the backup pulse. In some embodiments timing information associated with one or more features of the evoked response may be analyzed to determine whether an evoked response was triggered by the test pulse or the backup pulse.

Abstract: During a period of time comprising a plurality of cardiac cycles, a time relationship between ventricular events and atrial detections is established. Based on the relationship, a post-ventricular atrial refractory period is defined. The period includes an absolute atrial refractory period and a segmented relative atrial refractory period, wherein the segmented relative atrial refractory period includes at least one blanking window during which atrial detections of ventricular events have or are likely to occur.

Abstract: A method and apparatus for analyzing IEGM waveforms is disclosed. The method includes generating a long term ensemble average of a plurality of baseline IEGM waveforms and generating a short term ensemble average of at least a portion of the plurality of baseline IEGM waveforms. The method further includes determining a short term absolute point value as a function of the absolute value of the difference of the amplitude of the short term ensemble average and a test IEGM waveform and a long term absolute point value as a function of the difference of the amplitude of the long term ensemble average and the test waveform at a plurality of sample points. The disclosed method further includes detecting ischemia if the difference between the short term absolute point value and the long term absolute point value is greater than an ischemia detection threshold.

Abstract: A technique is provided for detecting episodes of cardiac ischemia based on an examination of the total energy of T-waves. Since cardiac ischemia is often a precursor to acute myocardial infarction (AMI) or ventricular fibrillation (VF), the technique thereby provides a method for predicting the possible onset of AMI or VF. Briefly, the technique integrates internal electrical cardiac signals occurring during T-waves and then compares the result against a running average. If the result exceeds the average by some predetermined amount, ischemia is thereby detected and a warning signal is provided to the patient. The maximum slope of the T-wave is also exploited. Techniques are also set forth herein for reliably detecting T-waves, which help prevent P-waves from being misinterpreted as T-waves on unipolar sensing channels. The T-wave detection technique may be used in conjunction with ischemia detection or for other purposes.

Abstract: An implantable medical device includes a first, short-range telemetry circuit; a second, long-range telemetry circuit; a first power system that powers the first telemetry circuit; and a second power system that powers the second telemetry circuit. The second power system includes an internal charging system and a rechargeable battery coupled to the internal charging system. The internal charging system may be configured for electromagnetic-inductive or RF-transmission coupling with an external charging system. A controller monitors the energy level of the rechargeable battery and provides an signal indicative of the level.

Abstract: A system is provided for backing up and synchronizing data stored within a set of programmers used for programming implantable cardiac stimulation devices such as pacemakers or implantable cardioverter defibrillators (ICDs). The data from the programmers that is backed up and synchronized includes programmer software, set up and configuration data, programming parameters, patient personal data, implantable device diagnostic data, and patient diagnostic data received from implanted devices. The implanted devices are classified into one or more groups and the programmer backup system merges and synchronizes data received from all programmers within a particular group. In other words, the backup system operates to ensure that each programmer within a particular group shares the same set up and configuration data, programmer software, patient contact data, and device diagnostic information.

Abstract: Techniques are described for detecting tachyarrhythmia and also for preventing T-wave oversensing using a narrowband bradycardia filter in combination with a narrowband tachycardia filter. In some embodiments, a separate wideband filter is also exploited. In one illustrative example, ventricular tachycardia (VT) is detected by: detecting a preliminary indication of VT using signals filtered by the bradycardia filter and, in response, confirming the detection of VT using signals filtered by the tachycardia filter. That is, the bradycardia filter, traditionally used only to detect bradycardia, is additionally used to provide a preliminary indication of VT. The tachycardia filter is then activated to confirm the detection of VT before therapy is delivered. In this manner, the tachycardia filter need not run continuously, but is instead activated only when there is some indication of possible VT, and hence power is saved.

Abstract: A peristaltic pump for conveying a fluid comprises a flexible tube having an outer surface and a lumen for carrying the fluid such as a therapeutic agent. The tube has a length defined by opposed ends of the tube, the outer surface of the body carrying a plurality of longitudinally spaced-apart electroactive polymer actuators. The plurality of actuators are adapted to be responsive to electrical signals for energizing the actuators sequentially along the length of the tube to move a lumen pinch-off along the length of the tube to thereby convey the fluid from one end of the tube to the other end by means of a peristaltic pumping action. The peristaltic pump may be incorporated into a medical lead, such as an endocardial pacing lead, carrying at least one electrode.

Abstract: An elastic framework configured to be positioned around a portion of the heart has a plurality of first regions and a plurality of second regions positioned relative to the first regions. The framework allows for the positioning of the first regions and second regions adjacent the outer surface of the heart and is structured so that the regions experience different movement effects in response to expansion and contraction of the heart. A sensor network having at least one motion sensor system associated with one of the first regions and second regions is associated with the framework. The motion sensor system outputs data responsive to the relative movement effects of the first and second regions. A communications system in communication with the sensor network provides for the transmission of motion data to a location remote from the framework.