Author + information
- Richard Lee, MD, MBA⁎ ( and )
- Patrick M. McCarthy, MD
- ↵⁎Northwestern University, Division of Cardiac Surgery, 201 East Huron Street, Suite 11-140, Chicago, Illinois 60611-2968
We read the recent report by Onorati et al. (1) with great interest. We agree with the investigators that the effect of surgical lesion pattern has been poorly investigated and had hoped that this report would clarify the success of different lesion patterns in patients undergoing concomitant surgery for atrial fibrillation. Unfortunately, we believe that the report has several inherent flaws that make the results inconclusive.
Most important, the left atrial group combined patients whose lesions were created using different types of energy sources. Myriad new ablation technologies have been introduced in the past decade, and the ability of each to create transmural linear lesions varies. Bipolar radiofrequency (RF) ablation appears more reliable in creating transmural lesions than monopolar RF ablation (2). The most likely reason that a change from monopolar RF to bipolar RF ablation occurred after December 2003 was the improvement in technology and thus outcomes. Fourteen of 32 patients undergoing the limited approach had lesions created using monopolar RF ablation. The “extensive” approach began in August 2004, after bipolar RF ablation was introduced. This suggests that the outcomes were inherently biased toward the “extensive group,” the group with the better energy source. Even in the 18 patients who underwent left atrial with bipolar RF ablation, the freedom from atrial fibrillation in this series was 53%. We recently reported our results in 175 patients using a left atrial–only approach, with freedom from atrial fibrillation of 81% (3). It is difficult to account for this disparity in results.
We congratulate Onorati et al. (1) for attempting to address a critical question: Does a more extended lesion set improve sinus restoration and survival? Unfortunately, given the heterogeneity of the procedures and energy sources, the question remains unanswered.
- American College of Cardiology Foundation