A method and system that includes an implantable cardioverter defibrillator (ICD) determining signal characteristics of a cardiac signal within a signal evaluation window positioned along a first portion of a cardiac cycle and determining whether a P-wave occurs within the signal evaluation window associated with the first portion of the cardiac cycle. The signal evaluation window is adjusted to be positioned along a second portion of the cardiac cycle in response to the P-wave not occurring within the signal evaluation window and signal characteristics of the cardiac signal are determined within the adjusted signal evaluation window. A determination is made as to whether a P-wave occurs in response to the signal characteristics determined within the adjusted signal evaluation window, and the ICD delivers a trigger signal to a leadless pacing device instructing delivery of ventricular pacing therapy by the leadless pacing device whenever a P-wave is determined to occur.

A cardiac stimulation system and associated capture management method are provided in which capture and device longevity are improved. The device determines a series of capture thresholds. Capture threshold is the minimum pulse level (pulse energy or pulse amplitude or pulse width) that captures the heart. Each determination requires delivery of pacing pulses at several (at least two) known levels (pulse energy, pulse amplitude and/or pulse width) over time. The individual determined capture thresholds are combined into a set and the variability of the set is used to set the safety margin. The greater the variability in the capture thresholds, the bigger the safety margin.

Capture management in a left ventricular leadless pacing device that includes determining an intrinsic P-wave of a sensed cardiac signal, sensing an electromechanical signal from an electromechanical sensor of the pacing device, and determining an intrinsic electromechanical atrioventricular interval of the sensed electromechanical signal in response to the sensed P-wave. Ventricular pacing is delivered via the one or more electrodes of the pacing device, and a ventricular pacing (V-pace) event is determined in response to the delivered ventricular pacing, and a V-pace to electromechanical response interval is determined in response to the V-pace event. A determination as to capture is detected is made in response to the intrinsic electromechanical atrioventricular interval and the V-pace to electromechanical response interval, and a pacing parameter is determined in response to determining whether capture is detected.

A medical device and medical device system for determining capture during delivery of a ventricular pacing therapy that includes a subcutaneous sensing device comprising a subcutaneous electrode to sense a subcutaneous cardiac signal and to emit a trigger signal in response to the sensed cardiac signal, an intracardiac therapy delivery device capable of being implanted within a left ventricle of a heart to receive the trigger signal and deliver the ventricular pacing therapy to the left ventricle in response to the emitted trigger signal, and a processor positioned within the subcutaneous sensing device, the processor configured to compare a beat of the subcutaneous cardiac signal sensed by the sensing device subsequent to the ventricular pacing therapy being delivered to a baseline template associated with a non-paced beat, and determine whether the delivered ventricular pacing therapy captures the left ventricle in response to the comparing.

A medical device system and method estimate a time from a first voltage of a power source of a medical device to a second voltage of the power source. The medical device includes a sensor coupled to the power source for generating a physiological signal. The medical device system determines a current drain from the power source required for generating the physiological signal and/or processing the physiological signal for detecting events from the physiological signal. A processor of the medical device system is configured to estimate the time from the first voltage of the power source until the second voltage based on at least the determined current drain.

In a threshold estimation apparatus, a setting unit sets an initial intensity value for each electrode. A selection unit randomly selects an electrode. A stimulation unit, via the selected electrode, stimulates a living subject at an intensity set for the electrode. A detection unit detects the presence or absence of a response evoked by the stimulation. An update unit reduces or increases the intensity associated with the selected electrode, based on the presence or absence of the response evoked by the stimulation. An estimation unit, if the thus updated intensity associated with each electrode satisfies a convergence condition, estimates a convergence value as a threshold associated with the electrode. The threshold estimation apparatus repeats these processes until thresholds associated with all electrodes are estimated. If the same electrode was consecutively selected, the time interval between a stimulation and a subsequent stimulation is adjusted.

Computer implemented methods and systems are provided for automatically determining capture thresholds for an implantable medical device equipped for cardiac stimulus pacing using a multi-pole left ventricular (LV) lead. The methods and systems measures a base capture threshold for a base pacing vector utilizing stimulation pulses varied over at least a portion of an outer test range. The base pacing vector is defined by a first LV electrode provided on the LV lead and a second electrode located remote from an LV chamber. The methods and systems designate a secondary pacing vector that includes the first LV electrode and a neighbor LV electrode provided on the LV lead. The methods and systems further define an inner test range having secondary limits based on the base capture threshold, wherein at least one of the limits for the inner test range differs from a corresponding limit for the outer test range. The methods and systems measure a secondary capture threshold associated with the secondary pacing vector utilizing stimulation pulses varied over at least a portion of the inner test range.

Systems and methods for cardiac pacing are described in this document. A medical system includes an electrostimulation circuit to generate His-bundle pacing (HBP) pulses to capture a His bundle, and LV pacing (LVP) pulses to capture a left ventricle. A sensing circuit may sense a cardiac activity, such as an atrial or an LV cardiac electrical activity. The system includes a control circuit controlling the delivery of HBP and LVP pulses. The HBP and LVP may be delivered concurrently or sequentially. In an example, the LVP pulses may be delivered based on a His-bundle capture status in response to the HBP pulse. The system may adjust one or more His-bundle stimulation parameters based on the His-bundle capture status.

A medical device comprises therapy delivery circuitry and processing circuitry. The therapy delivery circuitry is configured to deliver anti-tachycardia pacing (ATP) therapy to a heart of a patient. The ATP therapy includes one or more pulse trains and each of the one or more pulse trains includes a plurality of pacing pulses. The processing circuitry is configured to, for at least one of the plurality of pacing pulses of at least one of the one or more pulse trains, determine at least one latency metric of an evoked response of the heart to the pacing pulse. The processing circuitry is further configured to modify the ATP therapy based on the at least one latency metric.

A method for processing a cardiac signal represented as a function of time includes providing a number n of different threshold levels N.sub.i, with i=1 to n and n being greater than or equal to three; detecting, from a given time T and per threshold level N.sub.i, at least two successive intersections of the cardiac signal with the threshold level N.sub.i, considering a crossing per increasing and/or decreasing value of the cardiac signal with the threshold level N.sub.i; and determining at least one statistical parameter for the cardiac signal from the intersections of the cardiac signal with the at least three different threshold levels N.sub.i. The method may be implemented by a subcutaneous active implantable medical device having a control circuit configured to process a cardiac signal.