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.

An example system and method associated with identifying and treating a source of a heart rhythm disorder are disclosed. In accordance therewith, a spatial element associated with a region of the heart is selected. Progressive rotational activations or progressive focal activations are determined in relation to the selected spatial element over a period of time. The selecting and determining are repeated over multiple periods of time. A source parameter of rotation activations or focal activations is determined, wherein the source parameter indicates consistency of successive rotational activations or focal activations in relation to a portion of the region of the heart. The determining of a source parameter is repeated for multiple regions of the heart. Thereafter, representation of the source parameter is displayed for each of the multiple regions of the heart to identify a shape representing the source of the heart rhythm disorder.

Systems and methods are provided for managing patient activated capture of transient data by an implantable medical device (IMD). The systems and methods collect transient data using the IMD. The collected transient data is stored in a temporary memory section of the IMD. The IMD receives a patient activated storage request including activation information related to a patient designated trigger point from an external device. The IMD transfers a segment of the transient data from the temporary memory section to a long-term memory, wherein the segment of transferred transient data is based on the trigger point. The activation information includes an elapsed time corresponding to a duration of time between entry of the trigger point and issuance of the patient activated storage request by an external activation device.

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.

An extra-cardiovascular implantable cardioverter defibrillator (ICD) having a low voltage therapy module and a high voltage therapy module is configured to select, by a control module of the ICD, a pacing output configuration from at least a low-voltage pacing output configuration of the low voltage therapy module and a high-voltage pacing output configuration of the high voltage therapy module. The high voltage therapy module includes a high voltage capacitor having a first capacitance and the low voltage therapy module includes a plurality of low voltage capacitors each having up to a second capacitance that is less than the first capacitance. The ICD control module controls a respective one of the low voltage therapy module or the high voltage therapy module to deliver extra-cardiovascular pacing pulses in the selected pacing output configuration via extra-cardiovascular electrodes coupled to the ICD.

A cardiac pacemaker is disclosed for pacing cardiac tissue to improve synchrony between the atria and ventricles and/or between the left and right ventricles. A pulse generator is configured to deliver a pacing pulse to a patient's ventricle at an atrioventricular (AV) delay following a preceding atrial event. A sensing circuitry configured to sense a signal from the patient's ventricle following delivery of a said pacing pulse. A processing circuitry coupled to the pulse generator and the sensing circuitry and configured to control the pulse generator, the processing circuitry further configured to: (1) acquire from the sensed signal a set of features; (2) determine whether the ventricular pacing pulse effectively captures the patient's ventricle using the set of features; (3) determine whether one or more tissue latency conditions are present. The one or more pacing pulse parameters are adjusted, in response to determining that tissue latency is present.

Systems and methods for pacing cardiac conductive tissue are described. In an embodiment, a medical system includes an electrostimulation circuit to generate His-bundle pacing (HBP) pulses. A sensing circuit senses an atrial activation. A control circuit detects a retrograde atrial conduction timing, such as a His-to-atrial interval between the HBP pulse and the sensed atrial activation in response to the HBP pulse, and verifies capture status using the determined retrograded atrial conduction timing. Based on the capture status, the control circuit determines a HBP threshold, and the electrostimulation circuit delivers HBP pulses in accordance with the determined HBP threshold.

According to some methods, for example, preprogrammed in a microprocessor element of an implantable cardiac pacing system, at least one of a number of periodic pacing threshold searches includes steps to reduce an evoked response amplitude threshold for evoked response signal detection. The reduction may be to a minimum value measurable above zero, for example, as determined by establishing a noise floor. Alternately, amplitudes of test pacing pulses and corresponding post pulse signals are collected and reviewed to search for a break, to determine a lower value to which the evoked response threshold may be adjusted without detecting noise. Subsequent to reducing the threshold, if no evoked response signal is detected for a test pulse applied at or above a predetermined maximum desirable pulse energy, an operational pacing pulse energy is set to greater than or equal to the maximum desirable in conjunction with a reduction in pacing rate.

Embodiments described herein generally relate to methods and systems for monitoring and responding to changes in a patient's physiologic status. A method includes sensing pulmonary arterial pressure (PAP) and thoracic impedance of a patient at rest. The method also includes detecting, based on the sensed PAP, whenever the patient's PAP at rest is outside an acceptable range of PAP measures for the patient at rest, and detecting, based on the sensed thoracic impedance, whenever the patient's respiration at rest is outside an acceptable range of respiration measures for the patient at rest. Various different actions are triggered depending upon whether the patient's PAP at rest is outside the acceptable range of PAP measures for the patient at rest, and whether the patient's respiration at rest is within the acceptable range of respiration measures for the patient at rest. Other embodiments relate to similar methods performed at other levels of exertion.

Devices, systems, and techniques are described that use electric field imaging (often referred to as the sensed stimulation artifact representative of a delivered stimulus) as an informative feedback signal to provide closed loop control of electrical stimulation therapy. In some examples, the electric field imaging may be used in combination with other feedback signals, such as ECAP do monitor and adjust the delivered electrical stimulation therapy.