ANN ARBOR, MICHIGAN. Although radiofrequency (RF) ablation for atrial fibrillation (AF) has a very low mortality (comparable to that associated with a cataract operation), complications can and do arise during the procedure. Electrophysiologists at the University of Michigan now report on the rate of perioperative complications (complications occurring during the period between hospital admission and discharge) observed during 1642 RF ablation procedures, including 634 (39%) repeats, carried out on 1295 consecutive AF patients during the period January 2007 to January 2010. The mean age of the patients was 60 years, 74% were men, 53% had paroxysmal AF, and the remaining 47% had the persistent variety. Only 16% had heart disease, so the group essentially consisted of lone afibbers.

The overall incidence of perioperative complications was 3.5% with vascular access (initial insertion of the catheters in the femoral vein) being the most common at 1.9% (31 patients), followed by pericardial tamponade (fluid accumulation in the pericardium due to procedure-related rupture of the heart wall) in 20 patients (1.2%). The incidence of other complications was negligible and included 4 patients (0.2%) experiencing a TIA or ischemic stroke, 1 patient experiencing deep vein thrombosis, and 1 patient diagnosed with pulmonary vein stenosis. There were no procedure-related deaths, and no incidence of phrenic nerve palsy or atrioesophageal fistula. The vascular complications (1.9%) involved 12 patients with a major hematoma requiring blood transfusion, 17 patients with an arteriovenous fistula (abnormal connection between an artery and a vein), and 2 patients with a pseudoaneurysm (enlargement of an artery due to trauma) of the femoral artery. Successful surgical repair was performed in 9 of the 19 patients with arteriovenous fistula or pseudoaneurysm.

An analysis of various variables that could possible affect the incidence of vascular complications revealed that females had a 4-fold (OR=4.40) increased risk of experiencing this complication, possibly due to the fact that women have a significantly shorter common femoral vein than do men. Patients who had been on clopidogrel prior to the procedure had an almost 5-fold (OR=4.70) greater risk of vascular complications, while patients whose procedure was performed in July or August had an almost 3-fold (OR=2.71) increase in risk. This later observation is explained by the fact that physicians who had just started their internship in a teaching hospital are often entrusted with the initial catheter insertion. The only variable affecting the risk of pericardial tamponade was having undergone a previous RF ablation (OR=3.32). There was no evidence that ablation strategy, case volume, total procedure time, or total duration of radiofrequency energy application had any influence on complication rates.

Baman, TS, Oral, H, et al. Prevalence and predictors of complications of radiofrequency catheter ablation for atrial fibrillation. Journal of Cardiovascular Electrophysiology, Vol. 22, June 2011, pp. 626-31

Editor�s comment: This large study again underscores the fact that a radiofrequency ablation for AF is very safe if carried out at a high-volume center. It may be advisable though to avoid having the procedure during July or August if it is to be performed at a teaching hospital.