NEW YORK (Reuters Health) – Among patients undergoing left atrial radiofrequency catheter ablation for treatment of paroxysmal or persistent atrial fibrillation, the risk of symptomatic cerebral thromboembolism is low. However, a before-and-after imaging study shows that the occurrence of silent cerebral ischemia is substantial.
Dr. Fiorenzo Gaita at Ospedale Cardinal Massaia in Asti, Italy and colleagues conducted the study to get a better handle on the “the clinical implications of AF ablation and to better assess the risk profile of the procedure.” As they note in their report in the October 26 issue of Circulation, there’s little information about clinically silent cerebral ischemia, in contrast to clinically evident stroke, in the context of AF ablation.
The researchers studied 232 patients undergoing RF isolation of the pulmonary vein. All of them had pre-procedural and post-ablation MRI scans of the brain. Comparison of the imaging studies showed that 14% of the patients had new embolic lesions after the procedure. “In all 33 patients with a positive MRI, a neurological examination performed by an experienced neurologist was negative,” according to the report.
One patient had an overt stroke.
Cardioversion, electrical or pharmacologic, was required during the procedure to restore sinus rhythm in 62 patients (27%). This the investigators report.
In an accompanying editorial, Dr. Gregory F. Michaud with Brigham and Women’s Hospital, Boston, Massachusetts suggests that it’s possible that failure to convert rather than the ablation procedure per se may be the important factor in the occurrence of silent thromboembolism.
As for long-term ramifications, he writes, “the significance of silent cerebral embolism detected by MRI the day after a catheter ablation procedure is uncertain.”
Dr. Gaita and colleagues, however, are concerned, since patients often undergo more than one ablation procedure, leading possibly to cumulative damage.
“Certainly,” they write, “the occurrence of symptomatic stroke is dramatic for both the risk of death and the social and economic impact of the disease, but the evidence of silent embolic lesions is worrisome because these lesions add a dimension of further cerebral damage in a population at high risk for cerebral embolism and dementia.”
Reference:
Silent Cerebral Embolism During Catheter Ablation of Atrial Fibrillation. How Concerned Should We Be?
Circulation. 2010;122:1662-1663,1667-1673.
