Oral amiodarone prophylaxis significantly reduced the incidence of atrial tachyarrhythmias after cardiac surgery compared to placebo (16.1% vs 29.5%; HR 0.52; 95% CI 0.34-0.69; P<.001).
RCT (n=601)
Double-blind
Stratified
No
Does a brief perioperative course of prophylactic oral amiodarone reduce the incidence of atrial tachyarrhythmias after nonemergent CABG or valve surgery?
A brief perioperative course of oral amiodarone significantly reduces the incidence of postoperative atrial tachyarrhythmias in patients undergoing nonemergent cardiac surgery.
Effect estimate: HR 0.52 (95% CI 0.34-0.69)
Absolute Event Rate: 16.1% vs 29.5%
p-value: p=<.001
CONTEXT: Atrial tachyarrhythmias after cardiac surgery are associated with adverse outcomes and increased costs. Previous trials of amiodarone prophylaxis, while promising, were relatively small and yielded conflicting results. OBJECTIVE: To determine whether a brief perioperative course of oral amiodarone is an effective and safe prophylaxis for atrial tachyarrhythmias after cardiac surgery overall and in important subgroups. DESIGN, SETTING, AND PATIENTS: Double-blind randomized controlled trial of 601 patients listed for nonemergent coronary artery bypass graft (CABG) surgery and/or valve replacement/repair surgery between February 1, 1999, and September 26, 2003, at a tertiary care hospital. The patients were followed up for 1 year. INTERVENTION: Oral amiodarone (10 mg/kg daily) or placebo administered 6 days prior to surgery through 6 days after surgery (13 days). Randomization was stratified for subgroups defined by age, type of surgery, and use of preoperative beta-blockers. MAIN OUTCOME MEASURE: Incidence of atrial tachyarrhythmias lasting 5 minutes or longer that prompted therapy by the sixth postoperative day. RESULTS: Atrial tachyarrhythmias occurred in fewer amiodarone patients (48/299; 16.1%) than in placebo patients (89/302; 29.5%) overall (hazard ratio HR, 0.52; 95% confidence interval CI, 0.34-0.69; P<.001); in patients younger than 65 years (19 11.2% vs 36 21.1%; HR, 0.51 95% CI, 0.28-0.94; P = .02); in patients aged 65 years or older (28 21.7% vs 54 41.2%; HR, 0.45 95% CI, 0.27-0.75; P<.001); in patients who had CABG surgery only (22 11.3% vs 46 23.6%; HR, 0.45 95% CI, 0.26-0.79; P = .002); in patients who had valve replacement/repair surgery with or without CABG surgery (25 23.8% vs 44 44.1%; HR, 0.51 95% CI, 0.31-0.84; P = .008); in patients who received preoperative beta-blocker therapy (27 [15.3% vs 42 25.0%; HR, 0.58 95% CI, 0.34-0.99; P = .03); and in patients who did not receive preoperative beta-blocker therapy (20 16.3% vs 48 35.8%; HR, 0.40 95% CI, 0.22-0.71; P<.001), respectively. Postoperative sustained ventricular tachyarrhythmias occurred less frequently in amiodarone patients (1/299; 0.3%) than in placebo patients (8/302; 2.6%) (P = .04). Dosage reductions of blinded therapy were more common in amiodarone patients (34/299; 11.4%) than in placebo patients (16/302; 5.3%) (P = .008). There were no differences in serious postoperative complications, in-hospital mortality, or readmission to the hospital within 6 months of discharge or in 1-year mortality. CONCLUSION: Oral amiodarone prophylaxis of atrial tachyarrhythmias after cardiac surgery is effective and may be safe overall and in important patient subgroups. Clinical Trials Registration ClinicalTrials.gov Identifier: NCT00251706.
Mitchell et al. (2005) conducted an RCT in Patients undergoing nonemergent CABG and/or valve replacement/repair surgery (n=601). Oral amiodarone vs. Placebo was evaluated on Incidence of atrial tachyarrhythmias lasting 5 minutes or longer that prompted therapy by the sixth postoperative day (HR 0.52, 95% CI 0.34-0.69, p=<.001). Oral amiodarone prophylaxis significantly reduced the incidence of atrial tachyarrhythmias after cardiac surgery compared to placebo (16.1% vs 29.5%; HR 0.52; 95% CI 0.34-0.69; P<.001).