Catheter ablation associated with better outcomes than drug therapy in Thermocool AF trial

Quality of life also improved in patients who underwent catheter ablation.

Catheter ablation associated with better outcomes compared with drug therapy in Thermocool AF trial

Quality of life also improved in patients who underwent catheter ablation

Heart Rhythm Society's 30th Annual Scientific Sessions

Catheter ablation reduces the risk for recurrent atrial arrhythmias in patients who are unresponsive to antiarrhythmic drugs, results from a study suggested.

The final results of the trial evaluating the safety and efficacy of the NaviStar Thermocool irrigated-tip ablation catheter (Biosense Webster) were reported this morning at Heart Rhythm 2009.

Researchers enrolled 167 patients with AF who were nonresponsive to previous treatment with antiarrhythmic drugs and randomly assigned them 2:1 to undergo either catheter ablation (n=106) or receive antiarrhythmic drug therapy with a class I or III drug (n=61). The researchers followed the patients for one year. They assessed quality of life using the standardized SF-36 questionnaire at baseline and at three-month intervals during follow-up.

According to the study results, 63% of patients in the catheter ablation group were free of recurrent atrial arrhythmias at final follow-up, compared with 17% in the antiarrhythmic drug group (P<.001). Following a Cox regression analysis that incorporated baseline variables, the researchers reported that only treatment with catheter ablation was an independent predictor of freedom from recurrent atrial arrhythmias (HR=0.29; 95% CI, 0.18-0.45). While baseline SF-36 scores were similar between the study groups, mean scores improved in the catheter ablation group at three months (physical, P<.0001; mental, P<.0001) and remained improved at each subsequent interval. According to the researchers, there were no therapy-related deaths, but there was one death in the catheter ablation group at 284 days due to an acute MI.

“In patients with symptomatic paroxysmal AF unresponsive to prior therapy, catheter ablation led to significantly better outcomes compared [with] alternative drug therapy, including greater freedom from any symptomatic atrial arrhythmia occurrence while improving quality of life in multiple indices,” David J. Wilber, MD, a professor of medicine and director of the CV institute at Loyola University Medical Center in Maywood, Ill., said in a presentation. “In this trial, ablation is associated with a lower risk for major adverse events.” – by Eric Raible

This study shows that patients with recurrent AF who are not responsive to antiarrhythmic drug therapy treated with catheter ablation have improved quality of life. Although the study was randomized, the study is limited by having enrolled only patients who had already failed drugs and were, therefore, selected for anticipated failure again. Hence, the results unfortunately still do not provide an answer as to whether or not ablation as first-line therapy is superior to antiarrhythmic drug therapy. It is also important to recognize that the 63% success rate for catheter ablation is not all that different from the success rate of pharmacologic therapy in drug-naïve patients. If further studies show that the first-line therapy success rates for drug and ablation strategies are in fact similar, ablation would then clearly be the treatment of choice since success would remove the need for daily therapy and the negative effects of antiarrhythmic drugs on quality of life.

– Andrew E. Epstein, MD

Cardiology Today Editorial Board member

For more information:

Wilber D. LBCT I. Presented at: Heart Rhythm 2009; May 13-16; Boston.

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