“There was certainly no signal whatsoever of harm by taking patients to ablation early” in their management, agreed Dr. Ruskin. “I find that very reassuring and encouraging.”
CABANA (Catheter Ablation vs. Antiarrhythmic Drug Therapy for Atrial Fibrillation Trial) started in 2009 and enrolled 2,204 patients with documented, new-onset paroxysmal or persistent atrial fibrillation (AF) at 110 centers in 10 countries. Patients averaged about 68 years of age, with about 15% at least 75 years old, and in general were what Dr. Packer characterized as a high-risk group, with a high prevalence of comorbidities: 23% with sleep apnea, 10% with cardiomyopathy, 15% with heart failure, 10% with a prior stroke or transient ischemic attack, and just over a third in a New York Heart Association functional class II or III. About 43% had paroxysmal AF, about 47% had persistent AF, and the remaining patients had long-standing persistent AF. The median duration of AF at the time of entry was just over 1 year.
The clinicians treating the patients assigned to medical management could decide on a case-by-case basis whether to use rate or rhythm control, and about 12% of patients received rate control. The trial design specified pulmonary-vein isolation as the method for left atrial ablation.
In the intention-to-treat analyses, ablation was linked to a 14% relative reduction in the composite primary endpoint, a nonsignificant difference. All-cause mortality was a relative 15% lower in the ablation arm, also not statistically significant. A third prespecified, secondary endpoint, all-cause mortality plus cardiovascular hospitalization, was 17% lower in the ablated patients than in those on drug treatment in the intention-to-treat analysis, a statistically significant difference (P = .002).