Relation of Milrinone After Surgery for Congenital Heart Disease to Significant Postoperative Tachyarrhythmias

Milrinone reduces the risk of low cardiac output syndrome for some pediatric patients after congenital heart surgery. Data from adults undergoing cardiac surgery suggest an association between milrinone and an increased risk of postoperative arrhythmias. We tested the hypothesis that milrinone is an independent risk factor for tachyarrhythmias after congenital heart surgery. Subjects undergoing congenital heart surgery at our institution were consecutively enrolled for 38 months, through September 2010. The data were prospectively collected, including a review of full-disclosure telemetry and the medical records. Within 38 months, 603 enrolled subjects underwent 724 operative procedures. The median age was 5.5 months (range 0.0 to 426), the median weight was 6.0 kg (range 0.7 to 108), and the cohort was 45% female. The overall arrhythmia incidence was 50%, most commonly monomorphic ventricular tachycardia (n = 85, 12%), junctional ectopic tachycardia (n = 69, 10%), accelerated junctional rhythm (n = 58, 8%), and atrial tachyarrhythmias (including atrial fibrillation, atrial flutter, and ectopic or chaotic atrial tachycardia, n = 58, 8%). Multivariate logistic regression analysis demonstrated that independent of age <1 month, the use of cardiopulmonary bypass, the duration of cardiopulmonary bypass, Risk Adjusted classification for Congenital Heart Surgery, version 1, score >3, and the use of epinephrine or dopamine, milrinone use on admission to the cardiac intensive care unit remained independently associated with an increase in the odds of postoperative tachyarrhythmia resulting in an intervention (odds ratio 2.8, 95% confidence interval 1.3 to 6.0, p = 0.007). In conclusion, milrinone use is an independent risk factor for clinically significant tachyarrhythmias in the early postoperative period after congenital heart surgery.