Abstract: An implantable cardiac stimulation device and associated method provide automatic capture verification and threshold testing capabilities with an added high-threshold response algorithm and patient notification process. The stimulation device responds to higher than normal capture thresholds by permitting the stimulation pulse energy to be set above the fixed maximum pulse energy normally allowed by automatic capture verification techniques. In order to maintain comfortable yet effective stimulation, the high-energy stimulation is delivered in a bipolar configuration. The stimulation device alerts the patient of the change to high-energy output when it occurs. After the high-energy output is automatically set, one or more high-energy stimulation pulses are delivered in a unipolar configuration on a scheduled or event-triggered basis. A unipolar high-energy stimulation pulse is typically perceptible by the patient due to stimulation of excitable tissue surrounding the device housing.

Abstract: A system and method detects and terminates a repetitive non-reentrant ventriculo-atrial synchronous (RNRVAS) rhythm. The system and method is particularly adapted for use in an implantable cardiac stimulation device including a pulse generator that delivers atrial and ventricular pacing stimulation pulses to a heart which implements an AV delay and an atrial escape interval. The system includes a sensing circuit that senses cardiac activity of the heart and a detector responsive to the sensing circuit that determines if an RNRVAS rhythm is present. When an RNRVAS rhythm is present, a therapy control circuit lengthens the atrial escape interval for at least one cardiac cycle. In addition, the VA delay interval may be shortened by the same amount to maintain a consistent ventricular pacing rate.

Abstract: An implantable multi-chamber cardiac stimulation device includes flexibly programmable electrode stimulation configurations, and is capable of precisely controlling the stimulation sequence between multiple sites. The stimulation device provides a plurality of connection ports that allow independent connection of each electrical lead associated with a particular stimulation site in the heart. Each connection port further provides a unique terminal for making electrical contact with only one electrode such that no two electrodes are required to be electrically coupled. Furthermore, each electrode, whether residing on a unipolar, bipolar or multipolar lead, may be selectively connected or disconnected through programmable switching circuitry that determines the electrode configurations to be used for sensing and for stimulating at each stimulation site. The stimulation device allows for the programmable selection of each electrode terminal connection to a relatively positive or negative battery potential.

Abstract: An implantable cardiac stimulation device and method treats intrinsic ventricular rhythms lacking atrial transport to the heart. Once an arrhythmia detector detects an intrinsic ventricular rhythm lacking atrial transport, an atrial pulse generator paces the atria to restore atrial transport. The pacing is maintained at a constant rate for a first time period after which the pacing rate is decreased over a recovery time period. The device and method may also be employed for treating accelerated junctional rhythms, accelerated idioventricular rhythms, and first degree AV block, all of which result in inhibition of a dual-chamber pacemaker.

Abstract: An implantable multi-chamber cardiac stimulation device includes flexibly programmable electrode stimulation configurations, and is capable of precisely controlling the stimulation sequence between multiple sites. The stimulation device provides a plurality of connection ports that allow independent connection of each electrical lead associated with a particular stimulation site in the heart. Each connection port further provides a unique terminal for making electrical contact with only one electrode such that no two electrodes are required to be electrically coupled. Furthermore, each electrode, whether residing on a unipolar, bipolar or multipolar lead, may be selectively connected or disconnected through programmable switching circuitry that determines the electrode configurations to be used for sensing and for stimulating at each stimulation site. The stimulation device allows for the programmable selection of each electrode terminal connection to a relatively positive or negative battery potential.

Abstract: A system and method detects and terminates a repetitive nonreentrant ventriculo-atrial synchronous (RNRVAS) rhythm. The system and method is particularly adapted for use in an implantable cardiac stimulation device that includes a pulse generator that delivers atrial and ventricular pacing stimulation pulses and implements an atrial escape interval and a VA delay interval. This system includes a sensing circuit that senses cardiac activity of a heart and a detector that is responsive to the sensing circuit that determines if an RNRVAS rhythm is present. If an RNRVAS rhythm is present, a therapy control circuit causes the pulse generator to deliver a secondary atrial pacing pulse following a primary atrial pacing pulse delivered at the end of an atrial escape interval. The therapy control circuit may additionally cause the pulse generator to deliver a tertiary atrial pacing pulse following the next ventricular pacing pulse to prevent the occurrence of a retrograde P wave.

Abstract: An implant able multi-chamber cardiac stimulation device includes flexibly programmable electrode sensing configurations, and is capable of precisely controlling the stimulation sequence between multiple sites. The stimulation device provides a plurality of connection ports that allow independent connection of each electrical lead associated with a particular stimulation site in the heart. Each connection port further provides a unique terminal for making electrical contact with only one electrode such that no two electrodes are required to be electrically coupled. Furthermore, each electrode, whether residing on a unipolar, bipolar or multipolar lead, may be selectively connected or disconnected through programmable switching circuitry that determines the electrode configurations to be used for sensing and for stimulating at each stimulation site.

Abstract: An implantable multi-chamber cardiac stimulation device includes flexibly programmable electrode stimulation configurations, and is capable of precisely controlling the stimulation sequence between multiple sites. The stimulation device provides a plurality of connection ports that allow independent connection of each electrical lead associated with a particular stimulation site in the heart. Each connection port further provides a unique terminal for making electrical contact with only one electrode such that no two electrodes are required to be electrically coupled. Furthermore, each electrode, whether residing on a unipolar, bipolar or multipolar lead, may be selectively connected or disconnected through programmable switching circuitry that determines the electrode configurations to be used for sensing and for stimulating at each stimulation site.

Abstract: An implantable multi-chamber cardiac stimulation device includes flexibly programmable electrode sensing configurations, and is capable of precisely controlling the stimulation sequence between multiple sites. The stimulation device provides a plurality of connection ports that allow independent connection of each electrical lead associated with a particular stimulation site in the heart. Each connection port further provides a unique terminal for making electrical contact with only one electrode such that no two electrodes are required to be electrically coupled. Furthermore, each electrode, whether residing on a unipolar, bipolar or multipolar lead, may be selectively connected or disconnected through programmable switching circuitry that determines the electrode configurations to be used for sensing and for stimulating at each stimulation site.

Abstract: Location-specific diagnostic information is detected and recorded by the cardiac stimulation device for subsequent display using the external programmer device. The diagnostic information includes location-specific event records, counters and IEGM signals. The event records include event codes that distinguish among events occurring in the four chambers of the heart, such as sensed or paced events occurring within the left or right atria or the left or right ventricles. The counters separately count events occurring within the chambers of the heart. The IEGM signals are separately detected within the four chambers of the heart using a multiple sensing lead arrangement. The location-specific event records, counters and IEGM signals are ultimately transmitted to the external programmer, which displays graphic representations of the diagnostic information. The event records are displayed using distinct event marker icons which distinguish among the four chambers of the heart.

Abstract: A system and method detects and terminates a repetitive non-reentrant ventriculo-atrial synchronous (RNRVAS) rhythm. The system and method is particularly adapted for use in an implantable cardiac stimulation device including a pulse generator that delivers atrial and ventricular pacing stimulation pulses to a heart which implements an AV delay and an atrial escape interval. The system includes a sensing circuit that senses cardiac activity of the heart and a detector responsive to the sensing circuit that determines if an RNRVAS rhythm is present. When an RNRVAS rhythm is present, a therapy control circuit lengthens the atrial escape interval for at least one cardiac cycle. In addition, the VA delay interval may be shortened by the same amount to maintain a consistent ventricular pacing rate.

Abstract: A system and method detects and terminates a repetitive non-reentrant ventriculo-atrial synchronous (RNRVAS) rhythm. The system and method is particularly adapted for use in an implantable cardiac stimulation device that includes a pulse generator that delivers atrial and ventricular pacing stimulation pulses and implements an atrial escape interval and a VA delay interval. This system includes a sensing circuit that senses cardiac activity of a heart and a detector that is responsive to the sensing circuit that determines if an RNRVAS rhythm is present. If an RNRVAS rhythm is present, a therapy control circuit causes the pulse generator to deliver a secondary atrial pacing pulse following a primary atrial pacing pulse delivered at the end of an atrial escape interval. The therapy control circuit may additionally cause the pulse generator to deliver a tertiary atrial pacing pulse following the next ventricular pacing pulse to prevent the occurrence of a retrograde P wave.

Abstract: An implantable stimulator device provides automatic electrode polarity switching during an atrial capture verification mode. In systems using a bipolar sensing configuration in the atrium, polarity switching will be advantageous in detecting far-field R-waves for verification of capture. This automatic polarity switching feature is programmable and enables or disables automatic switching from bipolar to unipolar sensing at the onset of a far-field interval window and switching again back to bipolar pacing at the end of the far-field interval window.

Abstract: An improved system and method for performing autocapture/autothreshold detection in an implantable cardiac stimulation device or any device capable of stimulating some organ or tissue in the body. In some existing systems, loss-of-capture and capture decisions are based upon two consecutive cardiac events. However, such systems may be subject to subthreshold stimulation pulses that capture and lose capture on alternating pulses, trigeminy PVC sequences, or the like that require a higher stimulation pulse amplitude but cannot make this determination due to the two consecutive event requirement. Accordingly, in the present invention, the determination of whether there is a loss-of-capture is determined only according to paced events, i.e., ignoring intrinsic and PVC beats. Furthermore, the loss-of-capture determination is based upon X out of the last Y beats, where Y is greater than 2 and X is less than Y. Accordingly, consecutive loss-of-capture events are no longer required in determining the threshold level.

Abstract: A method and assembly for selectively actuating features of implanted medical devices with a magneto-static field. The method includes selectively exposing the implanted device to a static magnetic field source, selectively shielding the magnetic field source, and distancing the shielded magnetic field source from the medical device. One version of the assembly includes a permanent magnet and a displaceable shield assembly that shields the magnetic field generated by the magnet in one configuration and is displaceable to a second configuration wherein the magnetic field is at least partially exposed. In another version, the assembly is an electromagnet that can be selectively activated and deactivated. The electromagnet generates minimal magnet field when it is off.

Abstract: An implantable dual chamber stimulation device provides a novel detection scheme for automatically detecting atrial capture and performing an atrial pacing threshold assessment. The stimulation device preferably waits until the patient is at or near rest and monitors the patient's P-wave activity to determine an detection window where a next P-wave is expected to occur. The stimulation device then delivers an atrial pulse prior to the next detection window, and monitors the window to determine whether a P-wave occurs therein. If a P-wave does not occur, then atrial capture is present, while occurrence of a P-wave indicates absence of atrial capture. If atrial capture is absent, the stimulation device automatically determines an appropriate atrial pacing threshold by monitoring the detection window while adjusting the stimulation pulse energy level.

Abstract: An implantable dual chamber stimulation device provides a novel detection scheme for automatically detecting atrial capture and performing an atrial pacing threshold assessment. The stimulation device preferably waits until the patient is at or near rest and monitors the patient's P-wave activity to determine an detection window where a next P-wave is expected to occur. The stimulation device then delivers an atrial pulse prior to the next detection window, and monitors the window to determine whether a P-wave occurs therein. If a P-wave does not occur, then atrial capture is present, while occurrence of a P-wave indicates absence of atrial capture. If atrial capture is absent, the stimulation device automatically determines an appropriate atrial pacing threshold by monitoring the detection window while adjusting the stimulation pulse energy level.

Abstract: An implantable cardiac device, such as a pacemaker or an implantable cardioverter-defibrillator that has a control unit which is adapted to sample a time-varying parameter relating to either the patient's changing physiological condition or to the delivery of therapeutic electrical stimulation pulse to the heart at a sampling frequency. The control unit is adapted to increase the sampling frequency when the variation between successive measurements of the parameter exceed a preselected value. The control unit is further adapted to decrease the sampling frequency when the variation between successive measurements of the parameter are less than a preselected value. In alternate embodiments, the parameter to be sampled is capture threshold, sensing threshold, lead-tissue impedance, and battery performance.

Abstract: A system and method for identifying and displaying safety alert advisories. The system automatically performs a comparison of identification data with a safety alert advisory. The system stores identification data in a plurality of dedicated fields. Each of dedicated fields contains information related to the patient. Upon the telemetric retrieval of the data by an external programmer, the external programmer automatically cross-correlates the data in the dedicated fields with the safety alert advisories. Upon identification of a match between the data and one of the safety alert advisories, the identified safety alert advisory is displayed to a medical practitioner. In addition, the system provides a dedicated memory to store an advisory flag. The advisory flag is marked when the programmer identifies a safety alert condition that is relevant to one of the dedicated fields.

Abstract: 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.