Response to Letter Regarding Article, “Does Sodium Nitroprusside Decrease the Incidence of Atrial Fibrillation After Myocardial Revascularization? A Pilot Study”
We are thankful to Dr Singh for his interest in our study.1
We agree with Dr Singh that, in our study, patients had relatively preserved left ventricular systolic functions. However, our limited resources did not allow for further enrollment beyond our predetermined sample size.
Previous reports suggest that β-blockers suppress atrial fibrillation (AF) after surgery.2 Dr Singh requests information on the group of patients that had β-blocker withdrawal during the postoperative period. The rate of β-blocker withdrawal in this study was low (3 [4.8%] of the 63). No significant difference was found in the rates of postoperative atrial fibrillation when comparing the 2 patients randomized to SNP and the 1 patient randomized to placebo (5.8% versus 3.4%, respectively; P>0.20). However, because of the small size of this group, power was not sufficient to detect a significant effect. Amiodarone was administered only when patients had postoperative AF, and postoperative statins were used routinely at our clinic. We did not use digoxin in this study.
Atrial arrhythmia after cardiac surgery may have important consequences including cerebrovascular events,3 although during our study none of the patients showed symptoms of cerebrovascular events.
In response to Dr Singh, our study suggests that SNP has a beneficial effect in preventing AF after coronary artery bypass grafting. It is also the first clinical trial to evaluate the efficacy of SNP in prevention of the post–coronary artery bypass grafting AF. This study provides a strong platform for conducting a large-scale randomized trial and will make an important contribution to meta-analyses assessing the role of SNP in the treatment of this most common arrhythmia after coronary artery bypass grafting.
Cavolli R, Kaya K, Aslan A, Emiroglu O, Erturk S, Korkmaz O, Oguz M, Refik T, Tasoz R, Ozyurda U. Does sodium nitroprusside decrease the incidence of atrial fibrillation after myocardial revascularization? a pilot study. Circulation. 2008;118:476–481.
Aerra V, Kuduvalli M, Moloto AN, Srinivasan AK, Grayson AD, Fabri BM, Oo AY. Does prophylactic sotalol and magnesium decrease the incidence of atrial fibrillation following coronary artery bypass surgery: a propensity-matched analysis. J Cardiothorac Surg. 2006; 1: 6.