Patent ID: 7756570
Filing Date: 2010-07-13
Classification: A61N,Y10S

Abstract:
1. A method comprising: sensing, in vivo, a first waveform cycle corresponding to electrical cardiac activity, the first waveform cycle comprising a first portion and a second portion subsequent the first portion; comparing the amplitude of the first portion of the first cycle to a low sensitivity threshold; if the comparing indicates that the amplitude of the first portion of the first cycle does not meet or exceed the low sensitivity threshold then further comparing the amplitude of the second portion of the first cycle to a high sensitivity threshold; if the further comparing indicates that the amplitude of the second portion of the first cycle meets or exceeds the high sensitivity threshold then determining that ventricular fibrillation may exist; if ventricular fibrillation may exist, delivering a ventricular pacing pulse; detecting for an evoked response; and if an evoked response is detected, determining that ventricular fibrillation does not exist; terminating delivery of ventricular pacing pulses; sensing, in vivo, a subsequent waveform cycle corresponding to electrical cardiac activity, the subsequent waveform cycle comprising a first portion and a second portion subsequent the first portion; comparing the amplitude of the first portion to the low sensitivity threshold; and if the comparing indicates that the amplitude of the first portion meets or exceeds the low sensitivity threshold, confirming that ventricular fibrillation does not exist.