Stroke Rates Are High When Catheter Ablation of Atrial Fibrillation Fails

ORLANDO—In patients with atrial fibrillation (AF) who fail to achieve rhythm control after catheter ablation, the risk of ischemic stroke may approach 30% over five or more years of follow-up, despite optimized anticoagulation therapy, according to data from 1,002 consecutive patients presented at the 22nd Annual International AF Symposium.

Mihran Martirosyan, MD

The retrospective analysis was conducted in 1,002 patients who underwent catheter ablation after failing pharmacologic treatment of AF. Of these, 169 (17%) failed the ablation, but the focus of this study was on the subgroup of 67 catheter ablation treatment failures that have been followed for at least five years. All had been maintained on anticoagulation therapy.

Within this group, 18 (27%) had an ischemic stroke during follow-up. The average time to stroke after the first ablation procedure was 3.9 years.

Prior to being declared catheter ablation failures, the average number of ablation procedures in this long-term follow-up group was 1.7. In 55.2% of patients, the first ablation was performed with a cryoballoon. The remaining first ablations were delivered with radiofrequency. For a second or third ablation, the same techniques were commonly repeated, but 25% received a cavotricuspid isthmus ablation, and 12% underwent a VATS-Maze procedure.

There were no deaths in this series, in which the average patient age was 66. The average duration of AF was 12 years, the mean left atrial size was 45 mm, and the average left ventricular ejection fraction was 55%.

In this study, researchers defined catheter ablation failure as inability to regain rhythm control despite repeated ablation procedures. However, many patients who initially achieve rhythm control after catheter ablation have recurrence of AF over time. It is unclear whether patients who initially achieve but then lose rhythm control face the same high risk for stroke as seen in the Dutch series if followed long-term.

One study suggests that they may not. In a study by Bottoni et al of 631 consecutive patients who underwent a mean 1.5 catheter ablations before achieving rhythm control, 34% had an AF recurrence at one year. When followed for a mean 4.1 years of additional follow-up (5.1 years from the initial ablation), only 10% had a serious adverse event, such as heart failure or hemorrhage, and only 2% had a cerebrovascular event.

Numerous clinical studies have shown that catheter ablation is more effective than pharmacologic therapy for both regaining rhythm control in AF patients and reducing symptoms, according to Dr. Martirosyan, but these long-term follow-up data confirm that the risk of thromboembolic complications remains high in those who fail the initial catheter ablation. Of the 18 strokes, only four occurred in the first year of follow-up. The remaining strokes accrued slowly over time. Strokes were recorded up until 10 years after the ablation, the longest period that any patient was followed.

—Ted Bosworth