Incidence and prevention of cardiac tamponade complicating ablation for atrial fibrillation.

Cardiac tamponade complicating catheter ablation of atrial fibrillation (AF) occurs in approximately 1% of pulmonary vein isolation (PVI), and up to 6% of linear ablation procedures. We reviewed 348 consecutive AF ablation (including repeat) procedures over 1 year, which all included PVI, with additional linear lesions at the mitral isthmus in 73%, and cavotricuspid isthmus (CTI) in 76%. An irrigated-tip ablation catheter was used, with power limited to 25-35 W for PVI and 45-60 W for linear lesions. Tamponade occurred in seven men and three women (2.9% of the population) during the creation of linear ablation lesions. Mechanical perforations occurred in two patients, and "popping" during radiofrequency (RF) energy delivery at the mitral isthmus in six, and at the CTI in two patients. Peak RF power was significantly higher in patients with than without tamponade (53 +/- 4 W vs 48 +/- 7 W; P = 0.02), and was greater than 48 W in all cases of "popping." In the following year, RF power for linear ablation was limited to </=42 W. Among 398 procedures, tamponade occurred in four patients (1.0%; P = 0.047 vs first year), three from "popping" and one from mechanical trauma. Procedural success rate remained the same despite reduction of power. Risk of tamponade was highest during linear ablation, mainly associated with high energy delivery and "popping." Reducing the energy limited, though did not eliminate this complication.