Method and apparatus for detection of intrinsic depolarization following high energy cardiac electrical stimulation

A medical device comprising:

• a therapy delivery module configured to deliver a first electrical stimulation pulse to a patient that produces a post-stimulation polarization signal;
• a control module configured to start a pacing escape interval upon delivery of the electrical stimulation pulse;
• and
• a cardiac signal analyzer configured to:
• set a blanking interval upon delivery of the electrical stimulation pulse, the blanking interval extending beyond a time of an expected evoked response signal caused by the electrical stimulation pulse;
• obtain an electrical signal sensed across a pair of electrodes coupled to the medical device;
• determine a feature of the sensed electrical signal;
• compare the feature of the sensed electrical signal to criteria for identifying an intrinsic cardiac event during the post-stimulation polarization signal;
• identify the intrinsic cardiac event if the feature meets the criteria;
• wherein the control module is configured to restart the pacing escape interval in response to identifying the intrinsic cardiac event, and
• wherein the therapy delivery module is configured to deliver a second electrical stimulation pulse in response to expiration of the pacing escape interval.