Results from a randomized clinical trial comparing catheter ablation with rate control in patients with heart failure and persistent atrial fibrillation (AF) found peak oxygen consumption increased significantly in the ablation group. The study was published May 7 in the Journal of the American College of Cardiology.
ARC-HF (A Randomized Trial to Assess Catheter Ablation Versus Rate Control in the Management of Persistent Atrial Fibrillation in Chronic Heart Failure) was designed to evaluate the ability of a catheter intervention to improve objective cardiovascular function in patients with the frequently coexisting conditions of heart failure and persistent AF.
David G. Jones, MD, of Royal Brompton and Harefield hospitals in London, and colleagues selected change in peak oxygen consumption as a primary endpoint because it is a prognostic indicator. They used rate control because it is the standard of care for persistent AF in heart failure.
The study enrolled 52 adult patients with persistent AF, symptomatic New York Heart Association heart failure on optimal heart failure therapy, with left ventricular ejection fraction of 35 percent or less as assessed by radionuclide ventriculography. They were assigned 1:1 to either group between 2009 and 2012 with follow-up at three, six and 12 months.
Ejection fraction was assessed at baseline and 12 months.
Other baseline and periodic assessments were blood tests including B-type natriuretic peptide (BNP), cardiopulmonary exercise testing, two-dimensional echocardiography, Minnesota Living with Heart Failure Questionnaire (MLHFQ), six-minute walk test and 24-hour Holter electrocardiogram.
They determined that ablation was associated with improvements in peak oxygen consumption as well as other measures. Peak oxygen consumption increased by 2.13 ml/kg/min in the ablation group compared with a -0.94 ml/kg/min decrease in the rate control group at 12 months. There was a nonsignificant increase of peak oxygen consumption in the ablation group at three months.
MLHFQ score improved significantly in the ablation group at six and 12 months and nonsignificantly at three months compared with the rate control group. BNP showed a similar pattern but in the six-minute walk test distance tended to increase in both groups at six months with a nonsignificant increase in the ablation group and a decrease in the rate control group at 12 months.
Ejection fraction improved in the ablation group from 21.5 percent at baseline to 32.8 percent at 12 months compared with 24.9 percent to 30.2 percent in the rate control group. The left atrial area decreased in the ablation group at six months and 12 months and the right atrial area decreased at six months but much less at 12 months.
“Overall, these results suggest that rhythm control by ablation is a more effective strategy than medical rate control,” Jones et al wrote. They suggested that the nearly 20 percent benefit seen in peak oxygen consumption in the ablation group “might have favorable prognostic implications.”
They listed several study limitations, including that the results may not be generalizable because the patient population tended to be younger than in other trials. Nor did results apply to asymptomatic patients.
“Progressive improvement from three to 12 months implies that the effects reflect more than just sinus rhythm restoration, suggesting this method of rhythm control initiates a period of progressive systemic regression of the HF syndrome,” Jones et al wrote.
They added that two larger trials—CASTLE-AF and RAFT AF—will add more evidence about complication rates and outcomes when they wrap up in 2016, a sentiment that Mark D. O’Neill, MBBCh, DPhil, of St. Thomas Hospital in London, echoed in an accompanying editorial.
“Although the reported maintenance of sinus rhythm at one year is high, gradual attrition will likely occur, as has been widely reported for patients with persistent AF, necessitating a very frank and thorough discussion with patients at the outset about the potential risk and unproven longer-term benefits of such an aggressive interventional strategy,” O’Neill advised. He recommended assessing heart failure patients with persistent AF individually until the other trial data become available.