Patent ID: 7894893

Claim:
A method of operating an implantable cardiac system for discriminating between types of arrhythmia affecting one or more heart chambers, the method comprising: detecting cardiac beats associated with an arrhythmic episode; comparing a morphology of each cardiac beat to a plurality of representative beat morphologies stored in memory and respectively associated with a plurality of types of monomorphic arrhythmia; classifying the arrhythmic episode as a particular type of the plurality of types of monomorphic arrhythmia if at least x out of y beat morphologies of the arrhythmic episode are consistent with a representative beat morphology of the particular type of monomorphic arrhythmia based on the comparison, wherein x is a number greater than 1 and y is a number greater than x; determining that the arrhythmic episode is an unknown type of arrhythmia if the cardiac beats of the arrhythmic episode have been compared to each of the plurality of representative beat morphologies without being matched to any of the plurality of representative beat morphologies based on the comparison; determining whether or not a representative beat morphology can be acquired for the arrhythmic episode if the arrhythmic episode is the unknown type of arrhythmia; classifying the arrhythmic episode as a new type of arrhythmia if the arrhythmic episode is determined to be the unknown type of arrhythmia and if the representative beat morphology for the arrhythmic episode can be acquired for the arrhythmic episode; and classifying the arrhythmic episode as an uncharacterizable polymorphic arrhythmia if the arrhythmic episode is determined to be the unknown type of arrhythmia and if the representative beat morphology for the arrhythmic episode cannot be acquired, wherein detecting, comparing, determining, and classifying is performed by the implantable cardiac system.