Objectives

To compare the therapeutic strategies of rate control versus rhythm control in cardiac surgery patients who develop in-hospital postoperative atrial fibrillation or atrial flutter.

Background

Postoperative atrial fibrillation is the most common complication after cardiac surgery with an incidence of 20 to 50%. Consequences of postoperative atrial fibrillation include increases in rates of death, hospitalizations, and costs. There are currently two approaches to managing postoperative atrial fibrillation: heart-rate control (“rate control”) and rhythm control. The rhythm control method results in a more rapid conversion to sinus rhythm as compared to rate control, which may reduce thromboembolic risk, minimize exposure to anticoagulation, and result in faster restoration of functional capacity. However, rhythm control can also result in adverse effects due to the use of antiarrhythmic drugs or complications associated with cardioversion, which would be avoided by use of the rate control method. There is a lack of conclusive data and consensus regarding best practices for the management of postoperative atrial fibrillation, which has led to variations in practice. The CTSN-POAF trial was conducted to improve patient outcomes by determining the risks and benefits of rate control versus rhythm control.

Participants

The CTSN-POAF trial enrolled 2109 adult patients preoperatively. The patients were hemodynamically stable and undergoing elective cardiac surgery to treat coronary artery disease or heart-valve disease.

Among the patients enrolled, 695 developed postoperative atrial fibrillation and of these, 523 were randomized. Patients were randomized after experiencing postoperative atrial fibrillation that persisted for more than 60 minutes. Additionally, patients were randomized if they experienced recurrent episodes of atrial fibrillation during the index hospitalization period, noted as less than or equal to 7 days post-surgery. 262 patients were randomized to the rate control group and 261 patients were randomized to the rhythm control group.

Exclusion criteria included: history of atrial fibrillation, history of atrial flutter ablation, contraindication to study drugs, LVAD insertion or heart transplantation, and need for long-term anticoagulation.

Design

Patients were randomized into two treatment arms: rate control or rhythm control.

Patients in the rate control group received beta-blockers, calcium channel blockers, and/or digoxin to slow the heart rate to less than 100 beats per minute. Medication dose, frequency and duration were determined by physician. If sinus rhythm did not return after initial rate strategy, patients could be switched by their provider to rhythm control to improve hemodynamic status or to alleviate symptoms.

Patients in the rhythm control group received amiodarone with or without a rate-slowing agent. Direct-current cardioversion was recommended for patients with atrial fibrillation that persisted 24-48 hours post-randomization. It was recommended that patients continue to receive a maintenance dose of amiodarone for up to 60 days, barring any associated adverse events.

If patients remained in atrial fibrillation or had recurrent atrial fibrillation 48 hours after randomization, anticoagulation with warfarin was recommended for up to 60 days. The target INR was 2 to 3, and bridging with low-molecular-weight heparin was allowed. The atrial fibrillation status of patients was determined by: (1) telemetry during the first 7 days, and (2) electrocardiography at discharge, as well as during follow-up assessments performed at 30 days and 60 days.

The primary study end point was the total number of days in the hospital (including emergency department visits) within 60 days after randomization.

Conclusions

Rhythm control and rate control treatment arms were associated with equal number of days of hospitalizations and similar complication rates. Overall, neither method showed a significant clinical advantage over the other.

Gillinov AM, Bagiella E, Moskowitz AJ, et al. Rate Control versus Rhythm Control for Atrial Fibrillation after Cardiac Surgery. The New England journal of medicine. 2016;374(20):1911-1921. doi:10.1056/NEJMoa1602002.

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