THORACOSCOPIC VERSUS LAPAROSCOPIC PLACEMENT OF DEFIBRILLATOR PATCHES

Nonthoracotomy lead systems have been developed to reduce the morbidit y associated with cardioverter/defibrillator implantation. Total endoc ardial lead systems are effective in only about 50% of patients with s tandard monophasic waveforms; so patch placement is frequently require d. We developed a new patch design and surgical techniques for thoraco scopic patch placement over the left ventricle and laparoscopic placem ent under the diaphragm. To compare the efficacy of these approaches, patches were placed in both locations in pigs acutely with a right ven tricular coil serving as the anode for defibrillation. Defibrillation testing was performed, alternating between patches. The energies assoc iated with 50% (DF50) and 90% (DF90) probability of successful defibri llation with biphasic shocks with determined. Defibrillator thresholds were significantly lower with intrathoracic than with subdiaphragmati c patches. Animal autopsy following more than 30 shocks from each patc h revealed no gross damage to the lung or diaphragm in any animal.