Effect of ablation on left atrial function

WINSTON-SALEM, NORTH CAROLINA. A catheter ablation for the purpose of curing atrial fibrillation (AF) involves the creation of extensive scar tissue in the left atrium. An obvious question is, “Does the presence of this scar tissue impair the function of the left atrium?” A team of electrophysiologists from Wake Forest University, the Cleveland Clinic (OH), the University of Rochester, and Duke University recently set out to answer this question.

Their meta-analysis included 17 studies involving 869 patients who had undergone a radio frequency-powered catheter ablation for paroxysmal, persistent or permanent AF. Left atrium diameter, volume and function (ejection and emptying fraction) were evaluated prior to the ablation and at least one month following the ablation. Ablation success rates ranged from 53% to 82% for paroxysmal AF, from 60% to 76% for persistent, and from 47% to 54% for permanent.

The researchers observed a significant decrease in left atrial diameter and volume in patients who did not experience AF recurrence following their procedure. No such decreases were observed for patients who did experience recurrence. In analyzing data for left atrial ejection fraction and left atrial active emptying fraction , the researchers noted that there was no change in these parameters in patients who did not experience recurrence, while a noticeable decline (detrimental) was noted in those who did experience recurrence.

They conclude that a successful radio frequency catheter ablation does not adversely affect the function of the left atrium, and leads to a desirable reduction in left atrial diameter and volume. They point out that it is difficult to say whether the decrease in left atrial function observed in patients with AF recurrence is related to the continued presence of AF, or to the presence of excessive scar tissue produced by the ablation procedure.

Jeevanantham, V, et al. Meta-analysis of the effect of radiofrequency catheter ablation on left atrial size, volumes and function in patients with atrial fibrillation. American Journal of Cardiology, Vol. 105, 2010, pp. 1317-26

Editor’s comment: It is indeed comforting to know that a successful ablation does not impair the function of the left atrium, but rather results in a reduction of its diameter and volume which both, if elevated, are risk factors for heart failure.