Electrical cardioversion of atrial fibrillation using four defibrillation patches.

A 73-year-old female patient with hypertrophic cardiomyopathy presented with angina. During catheterization, she developed atrial fibrillation with a rapid ventricular response, associated with severe haemodynamic compromise. Two transthoracic patches (pro-padz, Zoll Medical Corporation, USA) were positioned in the anterior–posterior position, but a rectilinear biphasic 200-J shock (M-series defibrillator, Zoll Medical Corporation, USA) was unsuccessful. Four further shocks using hand-held paddles were also unsuccessful, despite manual pressure applied to improve contact, as were six shocks at various patch positions. Amiodarone (450 mg) was administered, but five additional 200-J biphasic shocks were ineffective. An increased thoracic electrical impedance was implicated as the cause of failure, because of the patient’s body habitus (height, 160 cm; weight, 75 kg; body surface area, 1.75 m). Prior to contemplating internal defibrillation, the impedance was decreased by increasing the defibrillation area with the use of four patches. Two patches were placed on the precordium; the insulation