Methods and devices are provided for managing anti-tachycardia pacing therapy delivered by an implantable medical device (IMD). The methods and devices detect events from cardiac signals sensed at electrodes of the IMD. The cardiac signals represent a ventricular tachycardia (VT) episode that includes at least a select number of VT events having a corresponding VT cycle length. The methods and devices analyze the VT cycle length to define an anti-tachycardia pacing (ATP) therapy that includes a first coupling interval and deliver a first ATP pulse that is spaced the first coupling interval after a reference refractory VT event sensed at the electrodes. The methods and devices deliver a second ATP pulse following the first ATP pulse by a non-stimulation segment that is at least one and three-quarters (1.75) times a projected VT cycle length.

A cardiac medical system, such as an implantable cardioverter defibrillator (ICD) system, receives a cardiac electrical signal by and senses cardiac events when the signal crosses an R-wave sensing threshold. The system determines at least one sensed event parameter from the cardiac electrical signal for consecutive cardiac events sensed by the sensing circuit and compares the sensed event parameters to P-wave oversensing criteria. The system detects P-wave oversensing in response to the sensed event parameters meeting the P-wave oversensing criteria; and adjusts at least one of an R-wave sensing control parameter or a therapy delivery control parameter in response to detecting the P-wave oversensing.

An implantable cardioverter defibrillator (ICD) performs a method that includes determining whether first criteria for detecting a ventricular tachyarrhythmia are met by a cardiac electrical signal. The ICD determines features from cardiac signal segment of a group of cardiac signal segments and determines whether a first portion of the features satisfy monomorphic waveform criteria and determines whether a second portion of the features satisfy supraventricular beat criteria. The ICD determines whether second criteria for detecting the ventricular tachyarrhythmia are met and withholds detecting of the ventricular tachyarrhythmia in response to the monomorphic waveform criteria and the supraventricular beat criteria being met.

Techniques are described for discriminating SVT and, in particular, rapidly conducting AF. The techniques include detecting an onset of a fast rate of ventricular events sensed from a cardiac electrical signal and detecting a pause in the fast rate of ventricular sensed events. A threshold number of ventricular event intervals required to detect a ventricular tachyarrhythmia is detected with each of the threshold number of ventricular event intervals being less than a tachyarrhythmia detection interval. Detection of the ventricular tachyarrhythmia and an electrical stimulation therapy for treating the ventricular tachyarrhythmia are withheld in response to at least the pause being detected.

A medical device is configured to detect an alternating pattern of signal features determined from consecutive segments of a cardiac electrical signal and determine a gross morphology metric from at least one segment of the cardiac electrical signal. The device is configured to detect cardiac event oversensing in response to detecting the alternating pattern and the gross morphology metric not meeting tachyarrhythmia morphology criteria. The medical device may withhold detecting an arrhythmia in response to detecting the cardiac event oversensing.

A medical device system, such as an extra-cardiovascular implantable cardioverter defibrillator ICD, senses R-waves from a first cardiac electrical signal by a first sensing channel and stores a time segment of a second cardiac electrical signal in response to each sensed R-wave. The medical device system determines a morphology parameter correlated to signal noise from time segments of the second cardiac electrical signal, detects a noisy signal segment based on the signal morphology parameter; and withholds detection of a tachyarrhythmia episode in response to detecting a threshold number of noisy signal segments.

Described herein are methods for use with an implantable system including at least an atrial leadless pacemaker (aLP). Also described herein are specific implementations of an aLP, as well as implantable systems including an aLP. In certain embodiments, the aLP senses a signal from which cardiac activity associated with a ventricular chamber can be detected by the aLP itself based on feature(s) of the sensed signal. The aLP monitors the sensed signal for an intrinsic or paced ventricular activation within a ventricular event monitor window. In response to the aLP detecting an intrinsic or paced ventricular activation itself from the sensed signal within the ventricular event monitor window, the aLP resets an atrial escape interval timer that is used by the aLP to time delivery of an atrial pacing pulse if an intrinsic atrial activation is not detected within an atrial escape interval.

Methods and devices for combining multiple signals from multiple sensing vectors for use in wearable or implantable cardiac devices. Signals from multiple vectors may be combined using weighting factors and/or by conversion to different coordinate systems than the original inputs, which may or may not be normalized to patient anatomy. Signals from multiple sensing vectors may be combined prior to or after several analytical steps or processes including before or after filtering, and before or after cardiac cycle detection. Cardiac cycle detection information may be combined across multiple sensing vectors before or after analysis of individual vectors for noise or overdetection. Cardiac cycle detection information may also be combined across multiple sensing vectors to identify noise and/or overdetection.

Approaches to rank potential left ventricular (LV) pacing vectors are described. Early elimination tests are performed to determine the viability of LV cathode electrodes. Some LV cathodes are eliminated from further testing based on the early elimination tests. LV cathodes identified as viable cathodes are tested further. Viable LV cathode electrodes are tested for hemodynamic efficacy. Cardiac capture and phrenic nerve activation thresholds are then measured for potential LV pacing vectors comprising a viable LV cathode electrode and an anode electrode. The potential LV pacing vectors are ranked based on one or more of the hemodynamic efficacy of the LV cathodes, the cardiac capture thresholds, and the phrenic nerve activation thresholds.

New and alternative approaches to the monitoring of cardiac signal quality for external and/or implantable cardiac devices. In one example, signal quality is monitored continuously or in response to a triggering event or condition and, upon identification of a reduction in signal quality, a device may reconfigure its sensing state. In another example, one or more trends of signal quality are monitored by a device, either continuously or in response to a triggering event or condition, and sensing reconfiguration may be performed in response to identified trends and events. In yet another example, a device may use a looping data capture mode to track sensing data in multiple vectors while primarily relying on less than all sensing vectors to make decisions and, in response to a triggering event or condition, the looped data can be analyzed automatically, without waiting for additional data capture to reconfigure sensing upon identification of the triggering event or condition. In another example a device calculates a composite cardiac cycle by overlaying signal morphology for a number of cardiac cycles and analyzes the composite cardiac cycle to calculate signal quality metrics.