During implantation of epicardial automatic defibrillator systems, occasional patients have difficulty in obtaining adequate defibrillation thresholds. Of 236 consecutive patients undergoing implantation of epicardial defibrillator systems, 18 patients received a 3-patch (n = 15) or 4-patch (n = 3) defibrillator system. Twelve patients who received a multiple-patch defibrillator system had a best 2-patch defibrillation energy requirement of greater-than-or-equal-to 30 J; in the remaining 6 patients less stringent clinical criteria were used in the decision to add a third defibrillator patch (defibrillation energy requirement >18 J in 4 patients, and >20 J in 2 patients). Technically, multiple-patch systems were made possible with either the use of Y-connectors or defibrillators allowing output to 3 patches. In 3 patients, addition of third epicardial patch still resulted in a defibrillation energy requirement of greater-than-or-equal-to 30 J; in these 3 patients, addition of a fourth patch resulted in a defibrillation energy requirement of less-than-or-equal-to 20 J. All patients receiving a multiple-patch defibrillator system had a reduction in defibrillation energy requirement, and 12 patients had a reduction in defibrillation energy requirement of greater-than-or-equal-to 10 J over the best 2-patch defibrillation energy requirement. In the patients who eventually had placement of a multiple-patch system, the best 2-patch defibrillation energy requirement was >18 J in 4 patients, >20 J in 2 patients, greater-than-or-equal-to 30 J in 9 patients, and >40 in 3 patients. After placement of a multiple-patch system, the defibrillation energy requirement was less-than-or-equal-to 24 J in 1 patient, less-than-or-equal-to 20 in 5 patients, less-than-or-equal-to 18 J in 8 patients, less-than-or-equal-to 15 J in 2 patients and less-than-or-equal-to 10 J in 2 patients. This improvement was significant (p<0.005). During implantable defibrillator placement associated with a high defibrillation energy requirement with a 2-patch system, placement of a 3- or 4-patch system may result in a marked improvement in defibrillation energy requirement.