Patent ID: 6987999

Claim:
A method of automatically alternating between at least a first counter electrode positioned adjacent a left cardiac chamber and a second remotely disposed counter electrode, for use in a cardiac defibrillator, comprising: detecting a fibrillation; delivering a first defibrillation waveform using a coil electrode positioned in a right chamber, and any of the first or second counter electrodes, so that the first defibrillation waveform follows a first pathway; determining if fibrillation was successfully terminated; if fibrillation was not successfully terminated, automatically delivering a second defibrillation waveform using the coil electrode and any of the first or second counter electrodes, so that the second defibrillation waveform follows a second pathway through the heart tissue, wherein the second pathway is different from the first pathway; and repeating an automatic alternating delivery of the first defibrillation waveform and the second defibrillation waveform until defibrillation is confirmed or the maximum allowed number of waveforms to be delivered has been reached.