[The efficacy of high- and low-energy intracavitary cardioversion in chronic atrial fibrillation refractory to transthoracic cardioversion].

BACKGROUND: The purpose of our study was to evaluate the efficacy and safety of intracavitary cardioversion (IC) with either high (HEIC) or low (LEIC) energy in patients with chronic atrial fibrillation (AF) refractory to external cardioversion. METHODS: Forty patients underwent IC with either high (30 pts) or low energy (10 pts); HEIC was performed by delivering one or more shocks between one electrode of the lead positioned in the right atrium and a back plate. The following energy values were used in sequence: 100, 200, 300 joules. In LEIC shocks were delivered between two custom-made decapolar leads (one in the coronary sinus and another one in the right lateral atrial wall) beginning from 50 Volts and increasing the voltage by steps of 50 Volts. Another catheter in the right ventricular apex was used for ventricular synchronization. RESULTS: Sinus rhythm was restored in 24/30 (80%) patients undergoing HEIC and in 10/10 (100%) patients undergoing LEIC. No serious or permanent complications occurred. CONCLUSIONS: HEIC and LEIC are effective in patients with AF refractory to external cardioversion. Both the procedures seem to be safe.