Patent ID: 8321002

Claim:
A processor-implemented method, comprising: sensing a plurality of composite cardiac signals at a plurality of patient-internal locations for a multiplicity of cardiac cycles; performing a plurality of source separations using the sensed composite cardiac signals; producing a cardiac signal vector indicative of a cardiac activation sequence of an area of the patient's heart based on each of the plurality of source separations; measuring an orientation of the cardiac signal vectors relative to a baseline established for the patient; detecting ventricular tachycardia (VT) based on the cardiac signal vector orientation measurements; and in response to detecting VT: determining variation of the cardiac signal vector orientation measurements, wherein determining the variation of the cardiac signal vector orientation measurements comprises: performing a subsequent source separation using sensed composite cardiac signals for each of a plurality of consecutive cardiac cycles after VT is detected; producing a subsequent cardiac signal vector based on each of the subsequent source separations; measuring an orientation of each subsequent cardiac signal vector relative to the baseline; and determining the variation of the subsequent cardiac signal vector orientation measurements; and discriminating between polymorphic ventricular tachycardia (PVT) and monomorphic ventricular tachycardia (MVT) based on the variation of the cardiac signal vector orientation measurements, wherein at least some of the method is implemented by a processor.