Cardiothoracic Surgical Trials Network: Rate vs. Rhythm Control for Atrial Fibrillation After Cardiac Surgery - CTSN: Rate vs. Rhythm Control for AF After Cardiac Surgery

Description:

The goal of the trial was to determine the efficacy and safety of a rate control strategy versus a rhythm control strategy using amiodarone and/or DC cardioversion (DCCV) for postoperative atrial fibrillation (AF) in patients undergoing cardiac surgery.

Contribution to the Literature: This study suggests that a rate control strategy is similar in efficacy to a rhythm control strategy using amiodarone and/or DCCV for postoperative AF in patients undergoing cardiac surgery.

Study Design

Patients with postoperative AF were randomized to either rhythm control (n = 261) or rate control (n = 262) strategies. Rhythm control was with amiodarone and/or DCCV if AF was >24 hours after initiation of amiodarone. Rate control was with beta-blocker, calcium channel blocker, or digoxin with a target heart rate of <100 bpm at rest. Persistent or recurrent AF patients received anticoagulation with Coumadin (target international normalized ratio [INR] 2-3) for at least 2 months.

Inclusion criteria:

  • Onset during index hospitalization (within 7 days of surgery) and either:
    •  AF/atrial flutter (AFL) persisting for > 60 minutes
    •  Recurrent episodes of AF/AFL
  • Total number of enrollees: 523
  • Duration of follow-up: Hospital discharge
  • Mean patient age: 69 years
  • Percentage female: 24%
  • Percentage diabetics: 31%

Other salient features/characteristics:

  • History of stroke: 6%
  • Valve disease: 55.1%
  • Surgery performed: coronary artery bypass grafting (CABG) alone: 41%, valve alone: 40%, CABG + valve: 20%

Principal Findings:

Primary outcome, total number of days within 60 days of surgery in the hospital, for rate vs. rhythm control: 5.1% vs. 5.0%, p = 0.76

Secondary outcomes (for rate vs. rhythm control):

  • Index length of stay: 4.3 vs. 4.3 days, p = 0.88
  • Cardiac arrhythmias: 4.3% vs. 4.6%, p = 0.8
  • Cerebrovascular thromboembolic event: 0.8% vs. 0.4%, p = 0.4
  • Death: 0.6% vs. 0.4%, p = 0.64
  • All readmissions: 18.5% vs. 18.5%, p = 0.99

Interpretation:

The results of this trial indicate that a rate control strategy is similar in efficacy to a rhythm control strategy (using amiodarone and DCCV) for postoperative AF in patients undergoing cardiac surgery. A rate control strategy could thus be considered first in these patients, similar to the management of patients with paroxysmal AF.

Postoperative AF is a common problem in patients undergoing cardiac surgery and is associated with high mortality and morbidity. A couple of points regarding the current trial are worth noting. There was a high rate of cross-over between the two arms (20-25%), which may have biased the result towards the null. Postoperative AF in valve patients may also be different than in CABG patients. Although inflammation is a common theme, valve patients may have left atrial (LA) enlargement and LA wall stress that may contribute to AF. More effective rhythm control strategies such as catheter-based ablation or other class III antiarrhythmic drugs need to be evaluated in future trials.

References:

Gillinov AM, Bagiella E, Moskowitz AJ, et al., on behalf of the CTSN. Rate Control Versus Rhythm Control for Atrial Fibrillation After Cardiac Surgrey. N Engl J Med 2016;Apr 4:[Epub ahead of print].

Presented by Dr. A. Marc Gillinov at the American College of Cardiology Annual Scientific Session, Chicago, IL, April 4, 2016.


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