Thoracoscopic versus laparoscopic placement of defibrillator patches

Nonthoracotomy lead systems have been developed to reduce the morbidity associated with cardioverter/defibrillator implantation. Total endocardial lead systems are effective in only about 50% of patients with standard monophasic waveforms; so patch placement is frequently required. We developed a new patch design and surgical techniques for thoracoscopic patch placement over the left ventricle and laparoscopic placement under the diaphragm. To compare the efficacy of these approaches, patches were placed in both locations in pigs acutely with a right ventricular coil serving as the anode for defibrillation. Defibrillation testing was performed, alternating between patches. The energies associated with 50% (DF50) and 90% (DF90) probability of successful defibrillation with biphasic shocks with determined. Defibrillator thresholds were significantly lower with intrathoracic than with subdiaphragmatic patches. Animal autopsy following more than 30 shocks from each patch revealed no gross damage to the lung or diaphragm in any animal.