Bordeaux-Pessac, France - New data from one of the groups that pioneered the catheter-ablation approach for the treatment of atrial fibrillation provides a revealing look at the long-term results of the radiofrequency procedure. Arrhythmia-free survival rates after a single catheter-ablation procedure are relatively low at five years, just 29%, but the long-term success increases to 63% when outcomes are measured after the last ablation procedure.
Investigators report that most AF recurrences occur in the first six to 12 months and that there is a "slow but steady decline in arrhythmia-free survival" in the later years. Overall, the group contends that the ablation strategy—with repeat interventions as needed-provides "acceptable"long-term relief from the arrhythmia.
Commenting on the results of the study for heartwire, Dr Hugh Calkins (Johns Hopkins University School of Medicine, Baltimore, MD), who was not affiliated with the study, said the gradual attrition rate in arrhythmia-free survival—in this trial there was an 8.9% annual recurrence rate following the last ablation attempt—confirms results observed in other studies.
"The bottom line is that everybody's results show the same thing, that atrial fibrillation is a complex arrhythmia, and that the longer you follow patients, the more recurrences they have," said Calkins. He added that those arguing ablation "cures" atrial fibrillation have been disproven. "Catheter ablation treats atrial fibrillation, it doesn't cure atrial fibrillation, at least in many patients," added Calkins. "And yes, you have to continue to follow patients, and this has important implications in terms of anticoagulation."
Moving from 29% to 63% after last ablation
The new data are the results of ablations performed at a single center in France. The electrophysiologists, including senior investigator Dr Michel Haissaguerre (Hôpital Cardiologique du Haut-Lévêque), one of the pioneers of atrial-fibrillation ablation, treated 100 patients with catheter ablation between January 2001 and April 2002 and followed them prospectively to determine the long-term outcomes. The analysis included patients with symptomatic disease and/or atrial fibrillation complicated by stroke, transient ischemic attack, or heart failure. Nearly two-thirds of patients had paroxysmal atrial fibrillation, while 22% had persistent and 14% had long-standing persistent atrial fibrillation.
After a single ablation procedure, arrhythmia-free survival rates were 40%, 37%, and 29% at one, two, and five years. Most recurrences occurred within the first six months, while arrhythmias recurred in 10 of 36 patients who maintained sinus rhythm for at least one year. The only predictor of a recurrence in a univariate analysis was the type of atrial fibrillation, with long-standing atrial-fibrillation patients 1.9 times more likely to have a recurrence when compared with individuals who had the paroxysmal or persistent form of the arrhythmia.
Among the 100 patients, 175 ablations were performed, with a median of two procedures performed per patient. When researchers examined recurrences since the last ablation, the arrhythmia-free survival rate increased, with investigators reporting rates of 87%, 81%, and 63% at one, two, and five years. Overall, 77 patients were arrhythmia-free at one-year follow-up, and 19 of these patients presented with a later recurrence. The presence of valvular heart disease and nonischemic dilated cardiomyopathy were independent predictors of recurrent atrial fibrillation in multivariate analysis.
The authors pointed out that the population was not representative of patients with atrial fibrillation in the real world, as these patients were predominantly younger, healthier, and not obese.
Overall, Dr.Calkins said the findings should not be interpreted negatively considering that other issues need to be judged when assessing the merits of atrial fibrillation.
"It isn't that catheter ablation doesn't work," he said. "This paper didn't look at atrial-fibrillation burden, which is a quality-of-life issue. You might have a patient that was in afib all the time, and you do an ablation, and they have a recurrence three years down the road, but that patient is still as happy as a clam, and their quality of life is better. Looking at recurrence as a yes-or-no question doesn't provide a full view of the benefit."
Regarding anticoagulation, Calkins said clinicians should continue to follow the Heart Rhythm Society consensus document that advises the use of the CHADS2 score to guide long-term anticoagulation strategies, and not use ablation as the guiding factor in their decision.
1. Weerasooriya R, Khairy P, Litalien J, et al. Catheter ablation for atrial fibrillation. J Am Coll Cardiol 2011; 57:160-166.