Amiodarone Prophylaxis

IN RESPONSE:

We agree with Mr. Craycraft's observation that similar cohort data were presented in the studies by Giri and associates (1) and by White and associates (2), both of which were included in our meta-analysis. The number of stroke end points (16 in Giri, 9 in White), the percentage of patients who received β-blockers (72.4% in Giri vs. 89.1% in White), and the percentage of patients who had valvular surgery (26.9% in Giri vs. 18.2% in White) are different in the 2 papers. Although the Annals of Thoracic Surgery identified the publication by White and colleagues as an “Original Article,” in retrospect, it appeared likely (to us) that the authors reported a substudy (rather than a duplicate) of AFIST (Atrial Fibrillation Suppression Trial). We spoke directly to Dr. White on 14 December 2005. He confirmed that the Annals of Thoracic Surgery article was a substudy of AFIST and that the same patient population was used.

We regret the inadvertent inclusion of duplicate cohort data in our meta-analysis. To assess the effect of including the patient data twice, we performed a meta-analysis that excluded the latter of these 2 publications (2). From the 9 remaining trials, we evaluated the effect of amiodarone on incidence of atrial fibrillation or flutter (relative risk, 0.65 [95% CI, 0.55 to 0.77]; P < 0.00001; I² = 0%); incidence of atrial fibrillation or flutter in patients receiving the drug preoperatively (relative risk, 0.63 [CI, 0.48 to 0.84]; P = 0.0001; I² = 0%); incidence of atrial fibrillation or flutter in patients receiving the drug perioperatively (relative risk, 0.65 [CI, 0.53 to 0.81]; P < 0.0001; I² = 5.6%); incidence of atrial fibrillation or flutter in patients receiving the drug orally (relative risk, 0.63 [CI, 0.48 to 0.84]; P = 0.001; I² = 0%); incidence of atrial fibrillation or flutter in patients receiving the drug intravenously (relative risk, 0.67 [CI, 0.51 to 0.88]; P = 0.003; I² = 7.7%); incidence of ventricular tachycardia and fibrillation (relative risk, 0.44 [CI, 0.29 to 0.67]; P = 0.0001; I² = 0%); incidence of stroke (relative risk, 0.44 [CI, 0.21 to 0.91]; P = 0.03; I² = 0%); and length of stay (weighted mean difference, −0.7 day [CI, −1.18 to − 0.22 days]; P = 0.005; I² = 22%).

Excluding the data from White and associates does not substantially alter the results of our meta-analysis. Our conclusion that amiodarone prophylaxis significantly reduces atrial fibrillation, major cardiovascular morbidity, and length of hospital stay after cardiac surgery remains firm.