Huge reduction of defibrillation thresholds using four electrode defibrillators

In the absence of a better solution, ventricular fibril- lation is treated by applying one or several large electri- cal shocks to the patient. The question of how to lower the energy required for a successful shock is still a cur- rent issue in both fundamental research and clinical prac- tice. In the study presented here we will compare defib- rillation applied through a four electrode device with the standard procedure using two electrodes. The method is tested through intensive numerical simulations. Here we have used a one dimensional geometry. At the level of the cardiac tissue, the bidomain and the modified Beeler- Reuter models were used. Three different shock waveforms are tested: monophasic and two types of biphasic shocks. The results are compared with those obtained with stan- dard two electrode device. A significant reduction in de- fibrillation thresholds is achieved for all the three tested waveforms when we use a four electrode device