Catheter ablation is better than pharmacotherapy to reduce atrial fibrillation episodes, but not to reduce deaths

Atrial fibrillation is a common arrhythmia that affects about 30 million people worldwide. New research shows that catheter ablation, a common cardiovascular procedure, does not appear to be more effective than a drug treatment for preventing stroke, death, and other complications in patients with atrial fibrillation. However, patients undergoing catheter ablation experience much greater relief from symptoms and a long-term improvement in quality of life. And they have fewer recurrences of their atrial fibrillation and fewer hospitalizations than those who only receive medication. You can learn more about this new research in the March 15 issue of JAMA.

This research, funded by the National Institute of the Heart, Lung and Blood (NHLBI), a member of the National Institutes of Health and industry collaborators, is the result of the catheter test Ablation versus antiarrhythmic treatment for atrial fibrillation (CABANA), the largest international randomized clinical trial comparing ablation of the left atrial catheter (which involves inserting long, narrow tubes to reach and apply the needle). energy (hot or cold) to destroy abnormal heart tissue) with modern drug therapy to reduce the consequences of atrial fibrillation. A related observational study using large data to support clinical trial evidence is published in the European Heart Journal. Read the press release.

Most people with atrial fibrillation have identifiable risk factors, such as high blood pressure or structural heart disease, and tend to be elderly. Some patients with atrial fibrillation are symptomatic, while others remain asymptomatic. Atrial fibrillation also increases the risk of stroke, heart failure and other serious health problems. Treating atrial fibrillation with antiarrhythmics has been difficult because of its limited effectiveness and potential adverse effects. Thus, catheter ablation therapy has become an alternative technique generally adopted to treat atrial fibrillation. Randomized controlled trials of modest size compared treatments, but there is still considerable uncertainty about the long-term benefits of ablation over drug treatment.

"We had known for a long time that doctors and patients were not satisfied with the drug treatment of atrial fibrillation, so we continued this study to determine if catheter ablation would provide more effective treatment for these patients. patients, "said Douglas Packer, MD, a cardiologist and Mayo Clinic specialist. the principal investigator of the study. "Although clinical trial data did not demonstrate that catheter ablation was better than pharmacotherapy to reduce death and stroke rates, they showed strong evidence of reduced recurrence of atrial fibrillation, as well as reduced mortality or cardiovascular hospitalizations. "

CABANA enrolled 2,204 patients in 126 centers in 10 countries between 2009 and 2016. Each patient presented with either early-stage or sub-treated atrial fibrillation. In the study population, the median age of patients was 68 years and 37% were women. There were significant comorbidities, such as hypertension, a history of stroke and diabetes. Patients were randomly divided into two groups of equal proportions for catheter ablation or pharmacotherapy.

The main comparison between catheter ablation and drug therapy has shown a risk of major complications such as death, stroke, severe bleeding and cardiac arrest of 14%, but the difference is not the same. was not statistically significant. Ablation significantly reduced cardiovascular mortality or hospitalization by 17% compared to drug therapy and reduced the number of atrial fibrillation recurrences by 48%. Compared to pharmacotherapy, ablation has resulted in clinically important improvements in quality of life and symptoms related to atrial fibrillation. These improvements have been maintained for five years.

In larger trials with longer follow-up, such as CABANA, patients do not always follow the badigned treatment. About nine percent of the patients undergoing ablation did not undergo surgery and nearly 30 percent of the pharmacotherapy group underwent ablation, the researchers said. Those "crosses" that have not received the badigned treatment may have affected the results of the study, says Dr. Packer. "You can not benefit from a therapy if you do not receive it," he says.

However, when the investigators reviewed the data for treatment received, the ablation group had significantly lower death rates (40%), as well as the combination of death, disabling stroke, severe bleeding, or cardiac arrest ( 33%), compared with patients who have only received medication, he says.

One year after the start of treatment, patients in both groups experienced substantial improvements in quality of life measures and measures related to atrial fibrillation, such as fatigue and shortness of breath. However, compared to drug therapy, the ablation has resulted in further improvements in quality of life and persistent symptoms over the five-year period, says Daniel Mark, MD, of the Duke Clinical Research Institute, who led the badysis of the quality of life.

For example, at the start of the study, 86% of the patients in the ablation group and 84% of the patients on medication had reported atrial fibrillation symptoms in the previous month. At the end of the study, only 25% of patients in the ablation group reported symptoms, compared to 35% of patients in the group undergoing pharmacotherapy, says Dr. Mark.

The Mayo Clinic and Dr. Packer have a financial interest in the Analyze-AVW mapping technology that may or may not have been used in this research. In accordance with the Bayh-Dole Act, this technology was licensed to St. Jude Medical (Abbott) and the Mayo Clinic, and Dr. Packer received annual royalties in excess of $ 10,000, the federal threshold for interest. important financial In addition, the Mayo Clinic holds an interest in the company for which AVW technology has been licensed.