Patent Document ID: 9597525
Application ID: 14705010
Patent Flag: 1

Claim One:
1. A method performed by a medical device, comprising: receiving a cardiac electrical signal from a patient's heart via a plurality of extracardiac electrode electrically coupled to the medical device; sensing cardiac events from the cardiac electrical signal; during a first operating state of the medical device, determining an estimated rate of the sensed cardiac events; transitioning from the first operating state to a second operating state of the medical device when the estimated rate of cardiac events meets a shockable rate detection criterion; setting a first signal analysis segment of the cardiac electrical signal during the second operating state; analyzing the first signal analysis segment to determine if shockable rhythm classification criteria are met for the first signal analysis segment; setting a plurality of T-wave oversensing (TWOS) analysis windows; analyzing cardiac events of the cardiac electrical signal to classify each TWOS analysis window of the plurality of TWOS analysis windows as one of TWOS and no TWOS, each TWOS analysis window being classified as TWOS when cardiac events during the TWOS analysis window satisfy TWOS criteria and classified as no TWOS when the cardiac events during the TWOS analysis window do not satisfy TWOS criteria; determining that TWOS detection criteria are met for the first signal analysis segment when a predetermined number of the plurality of TWOS analysis windows are classified as TWOS; classifying the first signal analysis segment as non-shockable in response to determining that the TWOS detection criteria are met; and remaining in the second operating state without advancing to a third operating state of the medical device when the TWOS detection criteria are met for the first signal analysis segment.