Acute hemodynamic effects of intravenous amiodarone treatment in paediatric cardiac surgical patients

Introduction: The haemodynamic response after an IV-loading dose of amiodarone followed by continuous infusion for various supraventricular and ventricular tachycardias was studied in children immediately after corrective surgery for congenital heart defects. Methods: Observational study over a 10-year period. Seventy-one out of 2651 patients (2,885 procedures, 2,106 bypass procedures) received amiodarone therapy for newly detected postoperative tachyarrhythmias. All patients received catecholamine infusions as standard post-op therapy to support cardiac function and output. In most cases a loading dose of amiodarone was given over 1-4 h followed by a continuous infusion. Catecholamine infusion dose requirements were monitored as was heart rate, blood pressure, central venous pressure, and sedation dose requirements pre treatment and at 0.5, 1, 2, 4, 8, 12 and 24 h after the begin of the amiodarone administration. Results: After 1 h there was a significant decrease of heart rate from 194.5 bpm (±31.9) to 157.5 bpm (±34.3) and an increase of the mean arterial blood pressure from 52.8 (±11.4) to 56.0 (±9.8) mmHg, with a subsequent decrease of filling pressures. The catecholamine dose required could be decreased as could the dose for sedation. Rate control was achieved at 277.4 min (±344) and rhythm control at 685.8 min (±988.5) respectively. Based on a preliminary interim analysis a specific treatment protocol was established and used in 32 patients. Conclusion: A slow bolus administration of 5 mg/kg amiodarone over at least 60 min followed by one or two additional boluses or a continuous infusion with 10-20 mg/kg day^-1 is a safe treatment strategy without the need for additional inotropic support and with dramatic improvement of heart rate, blood pressure and filling pressures. This protocol can be recommended for paediatric patients in the early postoperative setting.