Catheter ablation carries substantial risk for silent cerebral lesions
MedWire News: Patients undergoing left atrial catheter ablation for atrial fibrillation (AF) risk suffering asymptomatic cerebral thromboembolism during the procedure, report Italian researchers.
In common with previous studies, Fiorenzo Gaita (Cardinal Massaia Hospital, Asti) and colleagues found that symptomatic cerebral thromboembolism was rare during catheter ablation, occurring in just one (0.4%) of 232 patients studied.
All patients underwent transthoracic and transesophageal echocardiography before ablation, to rule out the presence of atrial thrombi, which could be dislodged during the procedure. The team also used irrigated-tip catheters, which is thought to reduce the risk for thrombus formation caused by radiofrequency energy application.
Nevertheless, comparison of magnetic resonance imaging scans performed before and after the procedure revealed new cerebral lesions in 33 (14%) patients.
Twenty-five patients had one new lesion, three had two, and five had three new lesions. Yet none of these patients had any neurologic deficits indicative of a cerebrovascular event.
Clinical factors such as age, history of stroke, type of AF, or prior antithrombotic treatment had no influence on the risk for silent lesions, report Gaita et al in the journal Circulation.
Two procedural factors affected risk, namely, activated clotting time was significantly lower in patients with than without silent cerebral lesions, at 269 versus 282 seconds, and cardioversion was performed in 45% versus 23%, respectively.
New lesions occurred in 26% of 62 patients who underwent electric or pharmacologic cardioversion. In contrast, the researchers report no new lesions in an additional group of 65 patients who underwent elective electric cardioversion without a prior attempt at catheter ablation.
"It seems therefore that conversion to sinus rhythm is not risky per se, but becomes significantly risky in the context of the ablation procedure," they suggest.
But in an accompanying editorial, Gregory Michaud (Brigham and Women's Hospital, Boston, Massachusetts, USA) said that "the failure to convert to sinus rhythm during catheter ablation… may be the important variable, not cardioversion itself."
He said: "A randomized study of electric or pharmacologic cardioversion at the end of the procedure is needed to answer the question definitively."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010
By Eleanor McDermid