Rate Control and Rhythm Control May Have Similar Effectiveness in Patients with New-Onset Postoperative Atrial Fibrillation

EBM Focus - Volume 11, Issue 21

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Reference - N Engl J Med 2016 May 19;374(20):1911 (level 2 [mid-level] evidence)

  • New-onset atrial fibrillation is common after cardiac surgery, but evidence evaluating optimal control strategies in postoperative settings is limited.
  • In analysis of 523 patients randomized to rate control vs. rhythm control strategies, there were no significant differences in duration of hospitalization, control of atrial fibrillation at hospital discharge and day 60, mortality, or adverse events.
  • Small differences in clinical course suggest that initial management should be determined by physicians and patients based on individual needs and preferences.

Atrial fibrillation after cardiac surgery is common and increases a patient’s risk of complications and death (J Thorac Cardiovasc Surg 2011 May;141(5):1305). Rate control with beta blockers or nondihydropyridine calcium channel blockers is often recommended as the initial approach in most patients with symptomatic atrial fibrillation, but this strategy may not be appropriate for all patients (Circulation 2014 Dec 2;130(23):e199, NICE 2014 Jun:CG180). While the American College of Cardiology/American Heart Association currently recommend rate control for patients with postoperative atrial fibrillation, this recommendation is largely based upon randomized trials in nonsurgical patient populations. A recent randomized trial compared rate control vs. rhythm control in hemodynamically stable patients with new-onset atrial fibrillation after cardiac surgery to further evaluate the best management in this specific patient population.

Thirty-three percent of the patients preoperatively enrolled in the trial developed new-onset postoperative atrial fibrillation, and 523 patients (mean age 69 years, 76% male) were randomized. Approximately 40% of patients had coronary artery bypass grafting, 40% had isolated valve surgery, and 20% had both. Therapy discontinuation or crossover occurred in 26.7% of patients randomized to rate control and 23.7% of the rhythm control group, most commonly for protocol prespecified reasons. Comparing rate control vs. rhythm control strategies, there were no significant differences in the median length of hospitalization (5.1 days vs. 5 days) or the proportion of patients with a stable heart rhythm without atrial fibrillation at either discharge (89.9% vs. 93.5%) or day 60 (84.2% vs. 86.9%). There were also no significant differences in hospital readmissions, mortality, serious adverse events, or any adverse event, though there was a small increase in the rate of serious pleural effusion in the rhythm control group (2 vs. 4.6 per 100 patient-months, p = 0.03)
The results of this trial suggest that rate control and rhythm control initial management strategies have similar clinical outcomes in patients with postoperative atrial fibrillation. There were some small differences between the two treatment strategies, however. Twenty-one percent of patients in the rate control group ultimately received amiodarone or direct-current cardioversion due to ineffectiveness or side effects of rate-control medications. More patients in the rate control group also met the protocol-specified indications for anticoagulation therapy, but the rate of warfarin prescriptions at discharge was similar between groups. Rhythm control was associated with a higher rate of discontinuation for side effects as well as a higher rate of serious pleural effusion. Overall, these differences did not materially affect rates of hospitalization, atrial fibrillation control, or death. Physicians should discuss therapy options with patients to determine the optimal treatment for each individual.

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