Patent ID: 7953489

Claim:
A method of cardiac signal analysis in an implantable medical device comprising a canister and a lead system, the implantable medical device including at least first, second and third electrodes, and being configured such that one or more pairs of electrodes can be selected for use in cardiac signal sensing, the method comprising: selecting and using a default sensing vector defined between a selected pair of electrodes to monitor a patient's cardiac rhythm; analyzing, monitoring and, if necessary, treating the patient's cardiac rhythm by: a) detecting electrical events using the selected default sensing vector b) determining whether detected events appear to be cardiac beats by performing beat validation of the detected events; c) using those events that appear to be cardiac beats to identify whether the patient is experiencing a malignant cardiac rhythm; and d) if a malignant cardiac rhythm is identified, delivering electrical stimulus to the patient; if detected events consistently fail to pass beat validation, determining the default sensing vector is unsuitable for cardiac signal analysis; and in response to determining that the default sensing vector is unsuitable, selecting a different default sensing vector.