Looking at Radiofrequency Ablation in Atrial Fibrillation

AUGUST 19, 2014
Andrew Smith
New research finds that people with atrial fibrillation (AF) who undergo radiofrequency ablation and maintain sinus rhythm are less likely than those who opt against the procedure to die of heart attack or heart failure.
The study, which appeared in Heart Rhythm, analyzed the 10-year medical history of 3,058 adults who had catheter ablation and found a 60% reduction in the expected rate of cardiovascular mortality.
“The study findings show the benefit of catheter ablation extends beyond improving quality of life for adults with atrial fibrillation. If successful, ablation improves life span,” said lead author Hamid Ghanbari, MD, MPH, an electrophysiologist at the University of Michigan Cardiovascular Center.
The study examined 10 years of data for 1,888 patients with paroxysmal AF and 1,170 with persistent AF.
Analysis with multivariate Cox models found no significant association between successful ablation and total cardiovascular events (hazard ratio [HR], 0.79; 95% confidence interval [CI], 0.48–1.29; P = .34) or between successful ablation and a reduction in all-cause mortality (HR, 0.86; 95% CI, 0.58–1.29; P = .48).
It did; however, find a large association between successful ablation and reduced mortality from cardiovascular events (HR, 0.41; 95% CI, 0.20-0.84; P = .015).
The significance of that association, moreover, persisted for patients in higher risk categories: older patients and those with diabetes, sleep apnea, low ejection fraction, and prior strokes or heart attacks.
The study authors say their result provides some of the first evidence showcasing that efforts to maintain sinus rhythm through radiofrequency ablation do actually reduce the risk of death from strokes and other cardiovascular events.
An editorial that accompanied the study noted it was one of the first looks at the long-term effects of ablation and concluded that the “thought provoking” findings will likely prove encouraging to patients with AF and doctors who treat them.
This new study, with its conclusion that successful ablations do provide concrete benefits, complements a far larger body of research into the success rate of ablations.
Doctors once hoped the procedure would offer a lifetime cure to virtually all people with AF, but several large studies (and larger meta-studies) show that symptoms recur in most patients after a couple of years.
Earlier this year, for example, the Journal of the American Medical Association published the results of a randomized trial that compared ablation with antiarrhythmic drugs in 127 AF patients at 16 medical centers in North America and Europe. After 2 years of monitoring, 36 patients (54.5%) in the ablation group were documented to experience at least one incidence of symptomatic or asymptomatic AF that lasted more than 30 seconds.
There is, however, hope for improvement.
Studies have identified at least some of the factors that separate successful and unsuccessful ablations – factor such as insufficient or excessive contact force on the heart wall during the procedure. There are also factors that improve success rates, elements that range from the number of procedures a doctor has performed to the type of anti-inflammatory used after the procedure.
Device makers, furthermore, have been developing second-generation catheters that may increase success rates.

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