Abstract: Cardiac pacing methods for an implantable single chamber pacing system, establish an offset rate for pacing at a predetermined decrement from either a baseline rate (i.e. dictated by a rate response sensor), or an intrinsic rate. Pacing maintains the offset rate until x of y successive events are paced events, at which time the offset rate is switched to the baseline rate for pacing over a predetermined period of time. Following the period, if an intrinsic event is not immediately detected, within the interval of the offset rate, the rate is switched back to baseline for pacing over an increased period of time. Some methods establish a preference rate, between the offset and baseline rates, wherein an additional criterion, for switching from the offset rate to the baseline rate, is established with respect to the preference rate.

Abstract: A catheter includes an inflation balloon and at least one electrode. The inflation balloon is inflatable within a vessel. The at least one electrode extends around at least a portion of a periphery of the inflation balloon. The at least one electrode is expandable as the inflation balloon is inflated, and contracts as the inflation balloon is deflated. The at least one electrode is held in place along a length of the inflation balloon with a tether member, which is secured at opposing distal and proximal ends of the inflation balloon.

Abstract: Cardiac pacing methods for an implantable single chamber pacing system, establish an offset rate for pacing at a predetermined decrement from either a baseline rate (i.e. dictated by a rate response sensor), or an intrinsic rate. Pacing maintains the offset rate until x of y successive events are paced events, at which time the offset rate is switched to the baseline rate for pacing over a predetermined period of time. Following the period, if an intrinsic event is not immediately detected, within the interval of the offset rate, the rate is switched back to baseline for pacing over an increased period of time. Some methods establish a preference rate, between the offset and baseline rates, wherein an additional criterion, for switching from the offset rate to the baseline rate, is established with respect to the preference rate.

Abstract: A medical device performs a method for computing an estimate of a physiological variable. The method includes sensing a physiological signal and measuring an event of the physiological signal. The device initializes a value of a long-term metric of the event measurement, wherein the long-term metric corresponds to a time interval correlated to a response time of the physiological variable to changes in the event. The estimate of the long-term metric is updated in a memory of the medical device using a previous long-term metric and a current measurement of the event. The device detects a need for computing the physiological variable and computes an estimate of the physiological variable using the updated long-term metric.

Abstract: A method and device for delivering anti-tachycardia pacing (ATP) therapy that includes an electrode to sense cardiac signals and to deliver the therapy, sensing circuitry, electrically coupled to the electrode, to detect the tachycardia event in response to the sensed cardiac signals, and a processor to control delivery of the therapy.

Abstract: A method and apparatus sense a cardiac electrical signal and determine a signal quality parameter of the cardiac electrical signal. A number of shock pulses to be delivered to a patient's heart is determined in response to the signal quality parameter. Each of the shock pulses are scheduled to be delivered at a unique offset from a T-wave shock interval in one embodiment of the invention.

Abstract: Cardiac pacing methods for an implantable single chamber pacing system, establish an offset rate for pacing at a predetermined decrement from either a baseline rate (i.e. dictated by a rate response sensor), or an intrinsic rate. Pacing maintains the offset rate until x of y successive events are paced events, at which time the offset rate is switched to the baseline rate for pacing over a predetermined period of time. Following the period, if an intrinsic event is not immediately detected, within the interval of the offset rate, the rate is switched back to baseline for pacing over an increased period of time. Some methods establish a preference rate, between the offset and baseline rates, wherein an additional criterion, for switching from the offset rate to the baseline rate, is established with respect to the preference rate.

Abstract: Methods for determination of timing for electrical shocks to the heart to determine shock strength necessary to defibrillate a fibrillating heart. The timing corresponds the window of most vulnerability in the heart, which occurs during the T-wave of a heartbeat. Using a derivatized T-wave representation, the timing of most vulnerability is determined by a center of the area method, peak amplitude method, width method, or other similar methods. Devices are similarly disclosed embodying the methods of the present disclosure.

Abstract: Methods for timing pacing pulses in an implantable single chamber pacemaker create a simulated, or virtual chamber in order to apply dual chamber-type algorithms and modes. For example, a virtual atrium may be constructed based on information provided by the ventricle, that is, the timing of actual intrinsic ventricular events, and the timing of paced ventricular events, both of which may be sensed as ventricular depolarization by electrodes of the implanted system.

Abstract: Cardiac pacing methods for an implantable single chamber pacing system, establish an offset rate for pacing at a predetermined decrement from either a baseline rate (i.e. dictated by a rate response sensor), or an intrinsic rate. Pacing maintains the offset rate until x of y successive events are paced events, at which time the offset rate is switched to the baseline rate for pacing over a predetermined period of time. Following the period, if an intrinsic event is not immediately detected, within the interval of the offset rate, the rate is switched back to baseline for pacing over an increased period of time. Some methods establish a preference rate, between the offset and baseline rates, wherein an additional criterion, for switching from the offset rate to the baseline rate, is established with respect to the preference rate.

Abstract: Methods for timing pacing pulses in an implantable single chamber pacemaker create a simulated, or virtual chamber in order to apply dual chamber-type algorithms and modes. For example, a virtual atrium may be constructed based on information provided by the ventricle, that is, the timing of actual intrinsic ventricular events, and the timing of paced ventricular events, both of which may be sensed as ventricular depolarization by electrodes of the implanted system.

Abstract: Cardiac pacing methods for an implantable single chamber pacing system, establish an offset rate for pacing at a predetermined decrement from either a baseline rate (i.e. dictated by a rate response sensor), or an intrinsic rate. Pacing maintains the offset rate until x of y successive events are paced events, at which time the offset rate is switched to the baseline rate for pacing over a predetermined period of time. Following the period, if an intrinsic event is not immediately detected, within the interval of the offset rate, the rate is switched back to baseline for pacing over an increased period of time. Some methods establish a preference rate, between the offset and baseline rates, wherein an additional criterion, for switching from the offset rate to the baseline rate, is established with respect to the preference rate.

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 medical device and associated method classify a tachycardia according to a site of origin of the tachycardia. Cardiac signals are sensed and a tachycardia event is detected in response to the sensed cardiac signals. Pacing pulses are delivered and a time interval corresponding to a distance traversed by a depolarization associated with the last one of the pacing pulses from a site of delivery of the plurality of pacing pulses is determined. The tachycardia event is classified according to a site of origin in response to the determined time interval.

Abstract: A method and apparatus for determining a T-wave shock interval sense a cardiac electrogram (EGM) signal comprising a T-wave signal. A T-wave center is determined from the EGM signal, and a T-wave shock interval is determined in response to determining the T-wave center. A T-wave shock is delivered at the T-wave shock interval computed based on the T-wave center.

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 atrial based pacing protocol promotes intrinsic conduction. An entire cardiac cycle is monitored for ventricular activity and permitted to lapse with ventricular activity. Ventricular pacing is available in a cardiac cycle immediately subsequent to such a skipped beat. When monitoring for intrinsic ventricular events, an event is expected within a given window. If no such event is detected, the cardiac cycle is truncated, leading to a shorter cycle that is devoid of ventricular activity. The subsequent cycle has a high likelihood of a ventricular sensed event and a greater than normal AV interval is provided prior to 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: An atrial based pacing protocol promotes intrinsic conduction. An entire cardiac cycle is monitored for ventricular activity and permitted to lapse with ventricular activity. Ventricular pacing is available in a cardiac cycle immediately subsequent to such a skipped beat. When monitoring for intrinsic ventricular events, an event is expected within a given window. If no such event is detected, the cardiac cycle is truncated, leading to a shorter cycle that is devoid of ventricular activity. The subsequent cycle has a high likelihood of a ventricular sensed event and a greater than normal AV interval is provided prior to pacing.

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.