OBJECTIVES: Postimplantation right ventricular dysfunction is associated with increased morbidity and mortality in ventricular assist device (VAD) recipients. This study aimed to determine the preoperative risk factors for severe right heart failure needing biventricular mechanical circulatory support in children with end-stage heart failure. METHODS: We reviewed data from 84 children supported with long-term VADs at the German Heart Institute Berlin between January 1999 and October 2010. Right ventricular assist device (RVAD) support was needed for 24 (29%) patients, and the other 60 (71%) were implanted with left ventricular assist devices (LVADs). RESULTS: The median age at implantation was 7 years (12 days-18 years), and the median support time was 41 days (1-432 days). Of the 84 patients, the overall survival to transplantation or recovery of ventricular function was 69%. Compared with children implanted with LVAD, patients receiving biventricular support had significantly higher postoperative mortality (P = 0.04). The multivariate logistic regression indicated that decreased milrinone use was the only preoperative factor independently associated with increased requirement for biventricular support (odds ratio: 0.1, 95% confidence interval: 0.04-0.64, P = 0.01). Children treated with milrinone preoperatively showed improved survival after implantation (P = 0.04). CONCLUSIONS: Paediatric patients needing biventricular support had significantly higher postoperative mortality. Preoperative milrinone use might decrease the risk of severe right ventricular failure requiring additional RVAD insertion and improve postimplantation survival in children with advanced heart failure.