New research indicates that catheter ablation is much more effective than drug treatments in patients with atrial fibrillation, a condition that affects more than 2 million Americans.
A news release from the Loyola University Health System reports that new research conducted by a team led by David Wilber, MD, director of the Cardiovascular Institute at Loyola University Chicago Stritch School of Medicine, indicates that catheter ablation works “dramatically better” than drug treatments in patients with atrial fibrillation (A-fib), a condition that affects more than 2 million Americans, with more than 150,000 new cases diagnosed each year.
For this study, the largest to date to compare ablation to drug therapy for atrial fibrillation, Wilber and colleagues recruited a cohort of 167 A-fib patients who had failed at least one drug; 106 patients were randomized to receive catheter ablation and the remaining 61 patients were prescribed a different medication for the treatment of A-fib. Patients (average age of 55 years) were recruited from 19 centers, including 15 US medical centers. Slightly more than one-third of the patients in this study were women; on average, patients had experienced A-fib symptoms for nearly six years and had failed at least one drug before entering the study.
According to the news release, “patients receiving ablation reported immediate and major improvements in their quality of life, which were maintained over the nine months they were followed. There were no significant quality-of-life improvements among patients who received drug therapy.” One year after undergoing catheter ablation, 66% of patients with A-fib were “free of any recurrent irregular heartbeats or symptoms,” compared with only 16% of those treated with medications. Results “were so convincing the trial was halted early.”
According to study results published in the January 27 issue of the Journal of the American Medical Association (JAMA), the patients who were treated with antiarrhythmic drug therapy received “a not previously administered, Food and Drug Administration—approved medication for treating AF (dofetilide, flecainide, propafenone, sotalol, or quinidine),” with the choice of medication left to the discretion of the investigator. Dosages were calculated based on recommendations from the American College of Cardiology/American Heart Association/European Society of Cardiology 2001 Practice Guidelines for Management of Patients with Atrial Fibrillation.
To be eligible for the catheter ablation group, patients received a CT scan or MRI scan within 30 days before the procedure, with follow-up imaging at three months and 12 months post-procedure. Pulmonary vein (PV) stenosis identified by CT or MRI scan was defined as “at least 70% reduction of the PV diameter compared with the baseline scan.” The study used independent laboratories to analyze transtelephonic, Holter monitors, and CT or MRI scan results.
According to the JAMA article, “most patients in the ADT group were assigned to either flecainide (20/56 [36%]) or propafenone (23/56 [41%]). Sotalol and dofetilide were assigned to 11 and 2 patients, respectively. For the catheter ablation group, confirmation of entrance block following PV isolation was achieved in all patients.” At 30-day follow-up, the authors reported “major treatment-related adverse events” in five patients in each group: one pericardial effusion, one pulmonary edema, one pneumonia, one vascular complication, and one heart failure in the ablation group; two patients with life-threatening arrhythmias and three with “disabling drug intolerance requiring discontinuation” in the drug therapy group.
In their commentary and discussion of the study results, the authors said that “these data strongly support the use of catheter ablation in patients with paroxysmal AF who do not respond to initial ADT. In patients with paroxysmal or short-duration persistent AF who have had limited prior drug exposure, 20% to 40% of patients treated with class I drugs or sotalol and 60% to 70% of patients treated with amiodarone have no recurrence of AF at 1 year.” These data, along with results from previous trials, “confirm that the efficacy of drug therapy for rhythm control may be considerably lower following previously failed drug trials compared with outcomes in patients not previously exposed to antiarrhythmic drugs.”
In this study, catheter ablation “was associated with elimination of symptomatic atrial arrhythmia in 70% of patients, and elimination of any atrial arrhythmia irrespective of symptoms in 63% of patients at 1 year.” Ablation was also associated with “an early and sustained reduction in symptom frequency and severity, and a parallel early and sustained improvement in [quality of life] scores,” indices which, noted the authors, “demonstrated little change over time” in patients treated with medication therapy.
While noting the current study’s limitations (including the fact that the study “did not address the long-term effect of either therapy on mortality, stroke risk, heart failure, or progression of paroxysmal AF to more persistent or permanent forms”), the authors concluded that this study “demonstrates the superiority of catheter ablation over ADT in the treatment of patients with paroxysmal AF who did not respond to 1 or more drugs. Catheter ablation provided significantly better rhythm control and improved QOL with a favorable safety profile. These findings argue for early use of catheter ablation therapy in patients with paroxysmal AF unresponsive to initial attempts with pharmacologic control.”