April 04, 2016

CHICAGO, IL ( updated ) — Either strategy may be more appropriate in individual patients, but overall, atrial fibrillation developing after heart surgery responds similarly to either rate-control or rhythm-control measures, according to a randomized trial with more than 500 patients who were assigned to one or the other strategy in conjunction with CABG, valve surgery, or both[1]. The two groups each experienced an average of about 5 days of hospitalization, including emergency-department visits, during the 60 days after the index surgery, which was the primary end point of the study exploring a common postoperative problem for which there is little consensus on therapy. Rates of persistent AF and of complications were also similar at 60 days.

Rate control consisted of treatment primarily with beta-blockers, and rhythm control entailed amiodarone and/or direct-current cardioversion in the study, which was published online in the New England Journal of Medicine to coincide with its presentation by lead author Dr A Marc Gillinov (Cleveland Clinic Foundation, OH) here at the American College of Cardiology (ACC) 2016 Scientific Sessions.

"There's no clear advantage of one treatment strategy over the other in terms of hospital days or complications," Gillinov told heartwire from Medscape. "Most of the time, more than 90% of the time, most of the atrial fibrillation is going to be gone by 60 days no matter what we do." But, he said, "I personally would favor rate control."

Consider the Individual Patient

Dr A Marc Gillinov

The trial's upshot, Gillenov said, is that "you’ve got to consider the individual patient and physician preference and choose one or the other strategy. An initial strategy of rate control in hemodynamically stable patients is probably reasonable, because you avoid the toxicity associated with the antiarrhythmic drug amiodarone, and because if you do need to switch from rate control to rhythm control, you can usually discern that need while the patient is still in the hospital and do it fairly easily, even then."

For physicians managing these patients, "the clinical message is much clearer. Clearly rate control is the preference," said Dr Hugh Calkins (Johns Hopkins Hospital, Baltimore, MD) as a panelist for Gillinov's presentation of the study. "I found the results of this to be very striking and very reassuring."

Physicians are "more comfortable" with rate-control drugs such as beta-blockers, which are also less expensive and entail less risk than associated with rhythm-control drugs or cardioversion, Dr Peter Kudenchuk (University of Washington, Seattle) said when interviewed. The latter, he said, "frankly doesn't offer anything better."

Not surprisingly, patients in the study assigned to rhythm control achieved sinus rhythm a bit earlier than those managed with rate control, but that didn't get them much. "About 40% of each group got anticoagulation," said Gillinov to heartwire .

"You can't say there's a net clinical benefit to either strategy across the entire group, but you can look at an individual patient and make a judgment." He said it's a "reasonable conclusion" to say the study advocates rate control as the first strategy to consider.

Stable Patients Without an AF History

The group randomized 523 hemodynamically stable patients with AF after cardiac surgery, none of whom had a prior history of AF, at 23 North American centers. They represented about one-fourth of a total cohort >2100 patients who were enrolled prior to surgery and followed for whether they developed AF.

Isolated CABG was performed in about 40%, isolated valve surgery in about 40%, and combined CABG and valve surgery in about 20%; the prevalence of postoperative AF was 28.1%, 33.7%, and 47.3%, respectively.

The 262 patients in the rate-control group and 261 assigned to rhythm control experienced a median of 5.1 days and 5.0 days in the hospital, respectively, over the first 60 days (P=0.76). The mean lengths of stay were 5.5 and 5.8 days, respectively (P=0.88).

There were no significant differences between patients in the two strategies in mortality, rate of serious adverse events, or thromboembolic or bleeding events—including cerebrovascular thromboembolism.

Still, of course, there are times to prefer rhythm control as the initial strategy, such as when the patient is highly symptomatic or hemodynamically unstable, said Gillinov. "If they're hemodynamically unstable, you'd probably want to electrically cardiovert them and load them with amiodarone." But the trial, which randomized only stable patients, doesn't address that.

The trial's bottom line is that when deciding between rate or rhythm control, "for the outcome they measured, days in the hospital, don't look for benefit there," observed Kudenchuk. If the patient is stable and isn't feeling bad, rate control is "the way to go" instead of rhythm control given that "we don't have any data that it changes hard end points for the patient."

The study was supported by a cooperative agreement funded by the National Heart, Lung, and Blood Institute and the National Institute of Neurological Disorders and Stroke of the National Institutes of Health and the Canadian Institutes of Health Research. Gillinov discloses being a consultant to or speaker for AtriCure, Medtronic, On-X, Edwards, and Abbott; receiving research funding from St Jude Medical and Tendyne; having equity interest in Clear Catheter and the Cleveland Clinic; and has the right to receive royalties from AtriCure for a left atrial appendage occlusion device. Disclosures for the coauthors are listed on the journal website.

 

 

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