Implantable medical device with real time T-wave oversensing detection
AssigneeMedtronic, Inc.
InventorsBruce D. Gunderson, Amisha S. Patel, Chad A. Bounds
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Abstract
An implantable cardioverter defibrillator (ICD) senses ventricular depolarizations (R-waves) in an electrogram signal to detect a ventricular tachycardia or fibrillation episodes. The EGM signal is also monitored in real time for characteristics that uniquely identify instances of T-wave oversensing. The ICD determines whether detection of a tachycardia or fibrillation episode is appropriate based upon counts of each of the unique characteristics evidencing T-wave oversensing.
Claims21
A method of controlling ventricular tachycardia (VT) and ventricular fibrillation (VF) detection in an implantable medical device, the method comprising:
- sensing R-waves in a ventricular electrogram (EGM) signal;
- obtaining time intervals between successive sensed R-waves;
- monitoring a plurality of characteristics indicative of T-wave oversensing;
- wherein monitoring the plurality of characteristics comprises maintaining a first count to track a number of occurrences of large successive interval differences and maintaining a second count to track a number of occurrences of a current time interval being approximately equal to a sum of two preceding time intervals, and
- withholding detection of a VT or VF in response to the first count and second count indicating presence of oversensed T-waves among the sensed R-waves.
An implantable medical device comprising:
- at least one sensing electrode to sense an EGM signal from a heart of a patient;
- a sense circuit for sensing events representing R-waves in the EGM signal;
- and
- a processor to identify T-wave oversensing by the implantable medical device based on counts of T-wave oversensing characteristics, the processor obtaining time intervals between successive sensed events, maintaining a first count of T-wave oversensing characteristics to track a number of occurrences of large successive interval differences, maintaining a second count of T-wave oversensing characteristics to track a number of occurrences of a current time interval being approximately equal to a sum of two preceding time intervals, and withholding detection of a ventricular tachycardia (VT) or ventricular fibrillation (VF) in response to the first count and the second count indicating presence of oversensed T-waves among the sensed R-waves.
Dependencies are inferred from the claim text.