Implantable medical device with real time T-wave oversensing detection
First Claim
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1. 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, andwithholding 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.
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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.
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Citations
21 Claims
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1. A method of controlling ventricular tachycardia (VT) and ventricular fibrillation (VF) detection in an implantable medical device, the method comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An implantable medical device comprising:
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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. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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Specification