Systems and methods for detecting atrial tachyarrhythmia are discussed. An exemplary atrial tachyarrhythmia detection system includes an arrhythmia detector circuit configured to receive physiologic information of a patient, generate a morphological similarity metric between the received physiologic information and a sinus rhythm (SR) template representing a morphology of conducted sinus beats during normal SR, and generate a morphological variability metric indicative of a variability in morphology between heart beats in the received physiologic information. The arrhythmia detector circuit may detect an atrial tachyarrhythmia episode the morphological similarity and morphological variability metrics.

A medical device is configured to set a post-atrial time interval in response to an atrial event and generate an event time signal in response to a ventricular electrical signal crossing an R-wave sensing threshold during the post-atrial time interval. The device accumulates oversensing evidence in response to the event time signal and adjusts a ventricular sensing control parameter based on the accumulated oversensing evidence in some examples.

A medical device is configured to receive sensed cardiac event data including a value of a feature determined from each one of a plurality of cardiac events sensed from a cardiac signal according to a first setting of a sensing control parameter. The medical device is configured to classify each value of the feature of each one of the sensed cardiac events as either a predicted sensed event or a predicted undersensed event according to a second setting of the sensing control parameter that is less sensitive to sensing cardiac events than the first setting. The medical device is configured to determine a predicted sensed event interval between each consecutive pair of the predicted sensed events and predict that an arrhythmia is detected or not detected based on the predicted sensed event intervals.

Described herein are methods, devices, and systems that improve arrhythmia episode detection specificity, such as, but not limited to, atrial fibrillation (AF) episode detection specificity. Such a method can include obtaining an ordered list of R-R intervals within a window leading up to a detection of a potential arrhythmia episode, determining a measure of a dominant repeated R-R interval pattern within the window, and comparing the measure of the dominant repeated R-R interval pattern to a pattern threshold. If the measure of the dominant repeated R-R interval pattern is below the pattern threshold, that is indicative of a regularly irregular pattern being present, and there is a determination that the detection of the potential arrhythmia episode does not correspond to an actual arrhythmia episode. Such embodiments can beneficially be used to significantly reduce the number of false positive arrhythmia detections.

A leadless pacing device may include a power supply providing a power supply voltage, a housing having a first end, a second end, and a side extending between the first end and the second end, and a set of electrodes supported by the housing and in communication with the power supply. The housing may be angled to follow a contour of a patient's heart when the housing is positioned within the coronary sinus of the patient's heart. In some cases, an angled portion of the housing may include a smooth-curve. In some cases, an angled portion of the housing may include a first portion of the housing and a second portion of the housing at an angle of less than one-hundred-eighty degrees with respect to the first portion of the housing. One or more of the electrodes may be exposed on a concave side of the angled housing.

An implantable medical device system is configured to detect a tachyarrhythmia from a cardiac electrical signal and start an ATP therapy delay period. The implantable medical device determines whether the cardiac electrical signal received during the ATP therapy delay period satisfies ATP delivery criteria. A therapy delivery module is controlled to cancel the delayed ATP therapy if the ATP delivery criteria are not met and deliver the delayed ATP therapy if the ATP delivery criteria are met.

An example medical device system includes memory configured to store information relating to an occurrence of a cardiac event in a patient and processing circuitry configured to determine the occurrence of the cardiac event in the patient. The processing circuitry is configured to determine at least one of a fall of the patient, a slumping posture of the patient, or a change from an upright posture to a non-upright posture of the patient and that the cardiac event is associated therewith in time. The processing circuitry is configured to, in response to determining that the cardiac event and the at least one of the fall of the patient, the slumping posture of the patient, or the change from the upright posture to the non-upright posture of the patient are associated in time, modulate a response to the cardiac event.

An implantable medical device includes a plurality of electrodes to detect electrical activity, a motion detector to detect mechanical activity, and a controller to determine at least one electromechanical interval based on at least one of electrical activity and mechanical activity. The activity detected may be in response to delivering a pacing pulse according to an atrioventricular (AV) pacing interval using the second electrode. The electromechanical interval may be used to adjust the AV pacing interval. The electromechanical interval may be used to determine whether cardiac therapy is acceptable or whether atrial or ventricular remodeling is successful.

Described herein are methods, devices, and systems that improve arrhythmia episode detection specificity, such as, but not limited to, atrial fibrillation (AF) episode detection specificity. Such a method can include obtaining an ordered list of R-R intervals within a window leading up to a detection of a potential arrhythmia episode, determining a measure of a dominant repeated R-R interval pattern within the window, and comparing the measure of the dominant repeated R-R interval pattern to a pattern threshold. If the measure of the dominant repeated R-R interval pattern is below the pattern threshold, that is indicative of a regularly irregular pattern being present, and there is a determination that the detection of the potential arrhythmia episode does not correspond to an actual arrhythmia episode. Such embodiments can beneficially be used to significantly reduce the number of false positive arrhythmia detections.

A cardiac treatment device, including: stimulation circuitry configured to generate a non-excitatory electrical signal which, when applied to ventricular tissue during a ventricular refractory period thereof improves a condition of heart failure in human patients; atrial arrhythmia detection circuitry; and decision circuitry which controls the stimulation circuitry to delivery said signal, also when said atrial arrhythmia detection circuitry detects an atrial arrhythmia.