摘要:
An apparatus comprises first and second sensing circuits, a template generator circuit, and a correlation circuit. The correlation circuit is configured to identify a first fiducial position in a third cardiac signal sensed using the first sensing circuit during a detected rhythm with elevated ventricular rate, align the template correlation features and the correlation features of a fourth cardiac signal using the first fiducial position, calculate a correlation using the correlation features of the template and the correlation features of the fourth cardiac signal, and iteratively searching for a replacement to the first fiducial position in the third cardiac signal according to the calculated correlation.
摘要:
A cardiac rhythm management device is configured to discriminate between ventricular and supraventricular tachycardias (referred to as SVT/VT discrimination) by utilizing a morphology criterion in which the morphology of electrogram waveforms during ventricular beats are analyzed to determine if the beats are normally conducted. After the delivery of a cardioversion/defibrillation shock, however, the intraventricular conduction system is left in a modified state which alters the subsequently generated electrogram signal. Use of the morphology criterion for SVT/VT discrimination is discontinued after delivery of such a shock and resumed after a predetermined minimum number of normally conducted ventricular beats has been detected.
摘要:
Methods and systems are directed to detecting atrial tachyarrhythmia. A plurality of A-A intervals is detected. The detected A-A intervals are selected and used to detect atrial tachyarrhythmia. Selecting A-A intervals may be based on determining that A-A intervals are qualified. Qualified A-A intervals may be determined if a duration of the particular A-A interval falls outside a predetermined duration range, for example. Qualified A-A intervals may also be determined based on events occurring between consecutively sensed atrial events of the particular A-A interval, and whether the duration of the particular A-A interval falls within the predetermined duration range, for example.
摘要:
A method of using an implantable medical device (IMD) to monitor a ventricular contraction rate of a subject, monitor an atrial contraction rate of the subject, declare tachyarrhythmia if the ventricular contraction rate exceeds the atrial contraction rate, and declare a slow tachyarrhythmia when the ventricular rate exceeds the atrial rate and the ventricular rate is less than a specified maximum pacing rate.
摘要:
An implantable medical device can include a hermetically-sealed implantable housing, an exposed first conductor located on or near the housing, and at least one insulated second conductor located near the exposed first conductor. In an example, the implantable medical device can include an isolation test circuit to provide a test stimulus to the exposed first conductor and configured to measure a portion of the test stimulus coupled to the second conductor.
摘要:
A system including an implantable medical device (IMD). The IMD includes a ventricular contraction sensing circuit that provides a sensed ventricular contraction signal, a timer circuit that provides a ventricular time interval between ventricular contractions, and a controller circuit coupled to the timer circuit, the controller circuit determines the ventricular contraction rate using the ventricular time interval. The controller circuit further includes a tachyarrhythmia detection module that declares tachyarrhythmia, in response to detecting a sudden rate increase, without comparing a ventricular rate or time interval to a respective tachyarrhythmia detection rate or time interval threshold.
摘要:
An apparatus comprises an implantable ventricular depolarization sensing circuit configured to provide a sensed ventricular depolarization signal, a timer circuit configured to provide a ventricular time interval between ventricular depolarizations, and a controller circuit communicatively coupled to the ventricular depolarization sensing circuit and the timer circuit. The controller circuit includes a ventricular tachycardia (VT) detection circuit configured to declare an episode of VT when a number of accelerated beats are detected, calculate a hysteresis VT detection threshold interval, and deem whether the episode of VT persists using the hysteresis VT detection threshold interval.
摘要:
A system detects events related to cardiac activity. The system comprises a primary cardiac signal sensing circuit, at least one secondary cardiac signal sensing circuit having a higher sensitivity than the primary sensing circuit, and a controller circuit coupled to the primary and secondary cardiac signal sensing circuits. The controller circuit determines a rate of depolarization using the primary sensing circuit and detects tachyarrhythmia using the rate. The controller circuit also detects tachyarrhythmia using the secondary sensing circuit and also deems the tachyarrhythmia valid if the controller circuit detects the tachyarrhythmia using both the primary and secondary sensing circuit.
摘要:
This document describes systems, devices, and methods that use multiple morphology templates for discriminating between rhythms, such as supraventricular tachyarrhythmias (SVTs) and ventricular tachyarrhythmias (VTs), for delivering a countershock in response to a VT episode, but withholding delivery of such a countershock in response to an SVT episode. In certain examples, the particular morphology used for storing morphological features is selected at least in part using a sensor-indicated activity level of a subject, or a metabolic need of the subject.
摘要:
An implantable medical device delivers anti-tachyarrhythmia therapies including anti-tachycardia pacing (ATP). If a detected tachyarrhythmia is classified as a type suitable for treatment using ATP, the implantable medical device selects one of an atrial ATP (A-ATP) mode, a ventricular ATP (V-ATP) mode, and a concurrent atrio-ventricular ATP (concurrent AV-ATP) mode according to the characteristics of the detected tachyarrhythmia. The concurrent ATP mode is an ATP mode during which the atrial pacing pulses and the ventricular pacing pulses are delivered concurrently. In one embodiment, the concurrent AV-ATP mode includes a synchronized atrio-ventricular ATP (synchronized AV-ATP) mode during which atrial and ventricular pacing pulses are delivered synchronously and an independent atrio-ventricular ATP (independent AV-ATP) mode during which atrial and ventricular pacing pulses are delivered concurrently but timed independently.