A method and medical device for determining oversensing that includes sensing cardiac signals from a first sensing channel, determining whether oversensing of the cardiac signal is occurring in response the cardiac signals sensed from the first sensing channel, determining a sensing parameter adjustment and initiating sensing of cardiac signals from a second sensing channel having the adjusted sensing parameter in response to oversensing being determined to occur, determining an oversensing value in response to the sensing in the second sensing channel, and storing the determined oversensing value.
