VATS-guided epicardial pacemaker implantation. Hand-sutured fixation of atrioventricular leads in an experimental setting.

BACKGROUND: In neonates and infants epicardial stimulation may be preferred to endocardial stimulation because of growth-associated lead problems and the risk of vascular complications associated with transvenous electrodes. This study analyzes the feasibility of atrioventricular implantation of a new epicardial lead using the video-assisted thoracic surgical (VATS) technique in an animal model.

METHODS: Bipolar steroid-eluting epicardial leads were implanted in seven young white pigs. In five animals bipolar atrial and ventricular pacing leads (n = 10) were inserted and fixed by the VATS technique, while two animals served as controls and underwent implantation through anterolateral thoracotomy. Surgical feasibility, pacing, and sensing thresholds of the leads as well as hemodynamic parameters during pacing were studied. Histological changes beneath the electrodes were evaluated 1 week after the implantation.

RESULTS: All animals survived the pacemaker lead implantation. One animal which underwent thoracotomy died because of irreversible ventricular fibrillation induced by rapid ventricular pacing. One animal in the VATS group exhibited intraoperative herniation of the heart through the pericardial window. All animals with left-sided VATS implantations demonstrated good individual pacing and sensing threshold values. The mean cardiac output was 1.6 times higher during AAI-mode pacing as compared to VVI-mode pacing at a heart rate of 140/min. One animal died postoperatively due to respiratory failure. No displacements of the pacemaker leads were observed in the survivors.

CONCLUSION: While VATS-guided implantation of epicardial, atrial, and ventricular leads is feasible, technical improvements of the system are mandatory for safe clinical application.