A Novel Defibrillation Tool: Percutaneously Delivered, Partially Insulated Epicardial Defibrillation

Objectives This study aimed to develop a percutaneous defibrillation system with partially insulated epicardial coils to focus electrical energy on the myocardium and prevent or minimize extracardiac stimulation. Background Epicardial defibrillation systems currently require surgical access. Methods We tested 2 prototypes created for percutaneous introduction into the pericardial space via a steerable sheath. This testing included a partially insulated defibrillation coil and a defibrillation mesh with a urethane balloon acting as an insulator to the face of the mesh not in contact with the epicardium. The average energy associated with a chance of successful defibrillation 75% of the time was calculated for each experiment. Results Of 16 animal experiments, 3 pig experiments had malfunctioning mesh prototypes such that results were unreliable; these were excluded. Therefore, 13 animal experiments were analyzed, 6 in canines (29.8 ± 4.0 kg) and 7 in pigs (41.1 ± 4.4 kg). The overall chance of successful defibrillation 75% of the time was 12.8 ± 6.7 J (10.9 ± 9.1 J for canines and 14.4 ± 3.9 J in pigs; p = 0.37). The lowest chance of successful defibrillation 75% of the time obtained in canines was 2.5 J, whereas in pigs it was 9.5 J. The lowest energy resulting in successful defibrillation was 2 J in canines and 5 J in pigs. There was no evidence of coronary vessel injury or trauma to extrapericardial structures. Conclusions Percutaneous, epicardial defibrillation using a partially insulated coil is feasible and seems to be associated with low defibrillation thresholds. Focusing insulation may limit extracardiac stimulation and potentially lower energy requirements for efficient defibrillation.