Background: Standard mapping and ablation of focal sources of atrial fibrillation are associated with very long procedure times and low efficacy. An anatomic approach to complete pulmonary vein isolation could overcome these limitations.
Methods and results: Fifteen patients with atrial fibrillation refractory to medication underwent circumferential isolation of the pulmonary veins by using a novel catheter, with an ultrasound transducer (8-MHz) mounted near the tip, in a saline-filled balloon. Twelve atrial foci and/or atrial fibrillation triggers were identified in 9 patients (pulmonary vein locations: left upper, 3; right upper, 6; right middle, 1; right lower, 1; and left inferior, 1). In 5 patients, lesions were placed in the absence of any mapped triggers. Irrespective of trigger mapping, circumferential isolation of both upper pulmonary veins was attempted in all patients. The lower pulmonary veins were ablated when sinus rhythm activation mapping revealed evidence of a sleeve of atrial muscle in the vein. The median number of lesions per patient required to isolate 1 pulmonary vein was 4 (range, 1 to 29). After ablation, no evidence of narrowing was seen with repeat venography or follow-up computed tomography scan. After a mean follow-up of 35+/-6 weeks, 5 patients had recurrence of atrial fibrillation. Three responded to drugs that were previously ineffective, and 2 remained in atrial fibrillation.
Conclusions: This novel ultrasound ablation system can successfully isolate multiple pulmonary veins. At early follow-up, this approach seems to be effective in preventing recurrent atrial fibrillation in a significant number of patients.