Efficacy of amiodarone on refractory ventricular fibrillation resistant to lidocaine and cardioversion during weaning from cardiopulmonary bypass in aortic valve replacement for severe aortic stenosis with left ventricular hypertrophy

Abstract

Intravenous injection of amiodarone, a class III anti-arrhythmic is widely used for persistent refractory arrhythmias. We present a case report suggesting the efficacy of amiodarone in refractory ventricular fibrillation (Vf) during weaning from cardiopulmonary bypass (CPB). A 66-year-old woman with hypertension had a medical examination as a result of an episode of palpitations and syncope. Echocardiography and an invasive hemodynamic study revealed severe aortic stenosis (AS) with left ventricular (LV) hypertrophy because of calcified degeneration in a congenital bicuspid aortic valve (AV). Aortic valve replacement (AVR) was scheduled under general anesthesia and CPB. Intraoperative diagnosis was AS with calcified AV, LV hypertrophy, and aneurysm of ascending aorta (Ao). AVR with a biological valve, artificial vessel replacement of ascending Ao, and excision of the outflow myocardial septum were performed under CPB with intermittent antegrade blood cardioplegia at a body temperature (BT) of 24°C. The patient suffered from Vf at a BT of 35.3°C. Vf was not responsive to lidocaine 100mg and 10 direct current (DC) shocks. After continuous intravenous infusion of amiodarone 225mg/h for 10min and a single intravenous injection of amiodarone 150mg followed by a single DC shock, she returned to normal sinus rhythm. Sinus rhythm was maintained by continuous intravenous infusion of amiodarone 60mg/h. Total CPB time was 5h 43min. Aortic cross-clamping time was 3h 50min. Administration of amiodarone is effective for refractory Vf resistant to lidocaine and cardioversion during weaning from CPB in cardiac surgery for heart diseases with LV hypertrophy.