Abstract: Systems and methods are described for implementing a catheter model to estimate shape of a deformable catheter in a three-dimensional space. The catheter model includes two or more model segments that correspond to two or more segments of the deformable catheter. Each model segment includes a length and location of model electrode(s) and/or model magnetic sensor(s) corresponding electrodes and/or magnetic sensors of the deformable catheter. Variable shape parameter define a curvature of the segment. Varying the shape parameters generates a plurality of potential catheter shapes. In conjunction with generating the potential catheter shapes, impedance and/or magnetic responses (e.g., measured responses) are obtained for the physical electrodes and/or physical magnetic sensors of the deformable catheter. Using a selected one (e.g., most likely) of the potential catheter shapes and the measured responses, the shape parameters are updated and a catheter shape is generated and displayed.

Abstract: Systems and methods are described for implementing a catheter model to estimate shape of a deformable catheter in a three-dimensional space. The catheter model includes two or more model segments that correspond to two or more segments of the deformable catheter. Each model segment includes a length and location of model electrode(s) and/or model magnetic sensor(s) corresponding electrodes and/or magnetic sensors of the deformable catheter. Variable shape parameter define a curvature of the segment. Varying the shape parameters generates a plurality of potential catheter shapes. In conjunction with generating the potential catheter shapes, impedance and/or magnetic responses (e.g., measured responses) are obtained for the physical electrodes and/or physical magnetic sensors of the deformable catheter. Using a selected one (e.g., most likely) of the potential catheter shapes and the measured responses, the shape parameters are updated and a catheter shape is generated and displayed.

Abstract: A preferred atrial-based pacing method and apparatus is provided using an intelligent cardiac pacing system to having the ability to continue atrial-based pacing as long as relatively reliable AV conduction is present. In the event that such relatively reliable AV conduction is not present, mode switching to a DDD/R or a DDI/R pacing mode while continually biased to mode switch back to atrial-based pacing. The standard or relatively reliable AV conduction may be changed either automatically or manually. This increases pacing that utilizes natural AV conduction however possible so as to gain all the benefits of cardiac contractile properties resulting therefrom, while tolerating the occasional missed ventricular depolarization (i.e., non-conducted P-wave). In the event where relatively reliable AV conduction is not present, the pacing mode is switched to a DDD/R mode while detecting a return of the relatively reliable AV conduction (and resulting mode switch to preferred atrial based pacing).

Abstract: A preferred atrial-based pacing method and apparatus is provided using an intelligent cardiac pacing system to having the ability to continue atrial-based pacing as long as relatively reliable AV conduction is present. In the event that such relatively reliable AV conduction is not present, mode switching to a DDD/R or a DDI/R pacing mode while continually biased to mode switch back to atrial-based pacing. The standard or relatively reliable AV conduction may be changed either automatically or manually. This increases pacing that utilizes natural AV conduction however possible so as to gain all the benefits of cardiac contractile properties resulting therefrom, while tolerating the occasional missed ventricular depolarization (i.e., non-conducted P-wave). In the event where relatively reliable AV conduction is not present, the pacing mode is switched to a DDD/R mode while detecting a return of the relatively reliable AV conduction (and resulting mode switch to preferred atrial based pacing).

Abstract: A preferred atrial-based pacing method and apparatus is provided using an intelligent cardiac pacing system to having the ability to continue atrial-based pacing as long as relatively reliable AV conduction is present. In the event that such relatively reliable AV conduction is not present, mode switching to a DDD/R or a DDI/R pacing mode while continually biased to mode switch back to atrial-based pacing. The standard or relatively reliable AV conduction may be changed either automatically or manually. This increases pacing that utilizes natural AV conduction however possible so as to gain all the benefits of cardiac contractile properties resulting therefrom, while tolerating the occasional missed ventricular depolarization (i.e., non-conducted P-wave). In the event where relatively reliable AV conduction is not present, the pacing mode is switched to a DDD/R mode while detecting a return of the relatively reliable AV conduction (and resulting mode switch to preferred atrial based pacing).

Abstract: Rate responsive pacing is limited in an atrial based pacing mode by the AV interval in order to avoid or minimize ventricular encroachment of atrial pacing. The AV or VA interval is used to permit rate responsiveness; modulate rate responsiveness or to determine a dynamic upper sensor rate.

Abstract: Pacing parameters are provided to address cross talk and intrinsic ventricular events occurring within a predefined blanking period following an atrial event. The parameters are used in conjunction with protocol for minimizing or reducing ventricular pacing, wherein ignoring intrinsic ventricular events during the blanking period might otherwise affect the performance of the protocol.

Abstract: An ADI/R mode is implemented using an intelligent pacing system to continually monitor ventricular response. This ensures AV conduction whenever possible so as to gain all the benefits of cardiac contractile properties resulting from native R-waves. In the event where AV conduction is blocked, the pacing mode is switched to a DDD/R mode to ensure a paced R-wave. Thereafter, subsequent to a completed interval of a P-wave, ADI/R pacing resumes to monitor ventricular response.

Abstract: An ADI/R mode is implemented using an intelligent pacing system to continually monitor ventricular response. This ensures AV conduction whenever possible so as to gain all the benefits of cardiac contractile properties resulting from native R-waves. In the event where AV conduction is blocked, the pacing mode is switched to a DDD/R mode to ensure a paced R-wave. Thereafter, subsequent to a completed interval of a p-wave, ADI/R pacing resumes to monitor ventricular response.

Abstract: An ADI/R mode is implemented using an intelligent pacing system to continually monitor ventricular response. This ensures AV conduction whenever possible so as to gain all the benefits of cardiac contractile properties resulting from native R-waves. In the event where AV conduction is blocked, the pacing mode is switched to a DDD/R mode to ensure a paced R-wave. Thereafter, subsequent to a completed interval of a p-wave, ADI/R pacing resumes to monitor ventricular response.

Abstract: A preferred atrial-based pacing method and apparatus is provided using an intelligent cardiac pacing system to having the ability to continue atrial-based pacing as long as relatively reliable AV conduction is present. In the event that such relatively reliable AV conduction is not present, mode switching to a DDD/R or a DDI/R pacing mode while continually biased to mode switch back to atrial-based pacing. The standard or relatively reliable AV conduction may be changed either automatically or manually. This increases pacing that utilizes natural AV conduction however possible so as to gain all the benefits of cardiac contractile properties resulting therefrom, while tolerating the occasional missed ventricular depolarization (i.e., non-conducted P-wave). In the event where relatively reliable AV conduction is not present, the pacing mode is switched to a DDD/R mode while detecting a return of the relatively reliable AV conduction (and resulting mode switch to preferred atrial based pacing).

Abstract: A method and device for delivering anti-tachycardia pacing pulses that may be used to treat episodes of atrial or ventricular tachycardia. Episodes of atrial or ventricular tachycardia can occur while the heart is at a normal rhythm or an accelerated rhythm. The method and device is directed to determining an estimate of action potential duration of a heart that experiences episodes of atrial or ventricular tachycardia for use in determining a pacing interval for anti-tachycardia pacing pulses that may more effectively terminate the tachycardia.

Abstract: A preferred atrial-based pacing method and apparatus is provided using an intelligent cardiac pacing system to having the ability to continue atrial-based pacing as long as relatively reliable AV conduction is present. In the event that such relatively reliable AV conduction is not present, mode switching to a DDD/R or a DDI/R pacing mode while continually biased to mode switch back to atrial-based pacing. The standard or relatively reliable AV conduction may be changed either automatically or manually. This increases pacing that utilizes natural AV conduction however possible so as to gain all the benefits of cardiac contractile properties resulting therefrom, while tolerating the occasional missed ventricular depolarization (i.e., non-conducted P-wave). In the event where relatively reliable AV conduction is not present, the pacing mode is switched to a DDD/R mode while detecting a return of the relatively reliable AV conduction (and resulting mode switch to preferred atrial based pacing).

Abstract: A preferred atrial-based pacing method and apparatus is provided using an intelligent cardiac pacing system to having the ability to continue atrial-based pacing as long as relatively reliable AV conduction is present. In the event that such relatively reliable AV conduction is not present, mode switching to a DDD/R or a DDI/R pacing mode while continually biased to mode switch back to atrial-based pacing. The standard or relatively reliable AV conduction may be changed either automatically or manually. This increases pacing that utilizes natural AV conduction whenever possible so as to gain all the benefits of cardiac contractile properties resulting therefrom, while tolerating the occasional missed ventricular depolarization (i.e., non-conducted P-wave). In the event where relatively reliable AV conduction is not present, the pacing mode is switched to a DDD/R mode while detecting a return of the relatively reliable AV conduction (and resulting mode switch to preferred atrial-based pacing).

Abstract: Rate responsive pacing is limited in an atrial based pacing mode by the AV interval in order to avoid or minimize ventricular encroachment of atrial pacing. The AV or VA interval is used to permit rate responsiveness; modulate rate responsiveness or to determine a dynamic upper sensor rate.

Abstract: A method and device for delivering a therapy in response to detection of abnormal cardiac rhythms that includes delivering a first therapy during a first delivery period, substantially simultaneous with coupling of a charging circuit and an energy storage device to generate stored energy on the energy storage device. A determination is made as to whether to deliver the first therapy during a second delivery period subsequent to the first delivery period in response to the predetermined level of stored energy not being generated on the energy storage device. The device then delivers the first therapy during a third delivery period subsequent to the second delivery period in response to the first therapy not being delivered during the second delivery period and the predetermined level of stored energy not being generated on the energy storage device.

Abstract: A method and device for delivering a therapy in response to detection of abnormal cardiac rhythms that includes a first circuit delivering a first therapy and a second circuit delivering a second therapy, the second circuit including an energy storage device for storing energy associated with the second therapy and a charging circuit selectively coupled to the storage device to generate the stored energy. A control circuit controls the first circuit and the second circuit to deliver the first therapy substantially simultaneous with the charging of the energy storage device in response to the predetermined event being detected, and decouples the energy storage device from the charging circuit during a redetect period subsequent to delivery of the first therapy. The control circuit recouples the energy storage device and the charging circuit in response to the microprocessor detecting the predetermined event during the redetect period.

Abstract: A method of predicting an arrhythmia, such as ventricular tachycardia, for example, in a medical device using a quantitative measure in order to allow assessment of patient risk and to enable preventative interventions by the device and clinicians. The trending of day and night average heart rates, along with patient physical activity can be analyzed to provide prediction of impending arrhythmia within weeks.

Abstract: Pacing parameters are provided to address cross talk and intrinsic ventricular events occurring within a predefined blanking period following an atrial event. The parameters are used in conjunction with protocol for minimizing or reducing ventricular pacing, wherein ignoring intrinsic ventricular events during the blanking period might otherwise affect the performance of the protocol.

Abstract: A method and device for delivering anti-tachycardia pacing pulses that may be used to treat episodes of atrial or ventricular tachycardia. Episodes of atrial or ventricular tachycardia can occur while the heart is at a normal rhythm or an accelerated rhythm. The method and device is directed to determining an estimate of action potential duration of a heart that experiences episodes of atrial or ventricular tachycardia for use in determining a pacing interval for anti-tachycardia pacing pulses that may more effectively terminate the tachycardia.