Implantation Sites of Pacemakers After Right Ventriculotomy and Complete Heart Block

THE IMPLANTATION of ventricular pacemaker electrodes in hearts with complete heart block is not an uncommon operative procedure. It is the purpose of this study to determine the most effective ventricular site, or sites, to implant pacemakers following a right ventriculotomy and complete heart block. Method Eight adult healthy mongrel dogs weighing 20 to 31 kg (44 to 68.2 lb) were anesthetized with intravenous thiopental sodium (2.5%), intubated, and placed on controlled ventilation. The chest was entered through the periosteal bed of the resected fifth rib. The right azygous vein was ligated and tapes were placed around the superior and inferior venae cavae. The pericardium was opened widely. Multicontact pacemaker electrodes with lead wires were sutured to the epicardial surface of the left ventricle at five points and to the epicardial surface of the right ventricle at five points, as indicated in Fig 1. During inflow occlusion a right ventriculotomy