Internal low-energy cardioversion: A therapeutic option for restoring sinus rhythm in chronic atrial fibrillation after failure of external cardioversion

Aim Conventional external cardioversion remains the technique of choice for restoration of sinus rhythm in patients with chronic atrial fibrillation ( AF). Recent reports have suggested that internal low-energy cardioversion i s efficient and safe in terminating AF in patients with failed external car dioversion. Methods and Results In 20 of 118 consecutive patients with spontaneous chro nic AF (>7/days), who underwent low-energy cardioversion, one or more attem pts at restoring sinus rhythm with external cardioversion had failed. Low-e nergy internal cardioversion was performed under light sedation. Shocks wer e delivered (using an external custom defibrillator) between two nonapolar catheters positioned in the right atrium (cathode) and in the coronary sinu s (anode). Heart disease was present in 12 and absent in eight patients ('l one' atrial fibrillation). Atrial fibrillation was established for a period ranging from 12 days to 53 months. Low-energy internal cardioversion resto red sinus rhythm in 15 of the 20 patients (75%) with a mean energy of 4.5 /- 1.2 J, a mean conversion voltage of 355 +/- 53 V and a mean impedance of 63 +/- 8 ohms. No complications were observed. With a mean follow-up of 6 +/- 7 months, 11 patients (73%) were in stable sinus rhythm. Conclusions This study provides evidence in support of low-energy internal cardioversion as a valuable therapeutic option in patients in whom conventi onal external cardioversion failed. This technique is safe and does not req uire peneral anaesthesia.