Off-line sensing method and its applications in detecting undersensing, oversensing, and noise

A method for performing and evaluating independent, off-line event sensing for collected electrograms, comprising:

• sensing an electrogram using an implantable medical device (IMD);
• the IMD determining locations of heart beats within the electrogram, resulting in a group of device-identified beat locations for the electrogram;
• storing the electrogram and device-identified beat locations in a memory location;
• retrieving, by an external computing device, the electrogram and device-identified beat locations from the memory location;
• after retrieving the electrogram from the memory location, determining, by the external computing device, locations of heart beats on at least a first channel of the electrogram using a multi-pass process, resulting in a group of multi-pass beat locations, wherein the multi-pass process comprises:
• identifying a preliminary group of beat location candidates within the first channel of the electrogram;
• eliminating a portion of the preliminary group of beat location candidates using a first algorithm resulting in a refined group of beat location candidates, wherein the first algorithm comprises comparing the amplitude of each of the preliminary beat location candidates with a first signal adaptive threshold;
• and
• eliminating a portion of the refined group of beat location candidates using a second algorithm resulting in the group of multi-pass beat location candidates, wherein the second algorithm comprises comparing the amplitude of each of the preliminary beat location candidates with a second signal adaptive threshold;
• and
• comparing the device-identified group of beat locations to the multi-pass group of beat locations identified using the multi-pass method.