A 4-month-old girl, weighing 6.65 kg with an estimated body surface area of 0.32 m 2, suffering from ALCA, was scheduled for reimplantation of the left coronary artery. Preoperatively, a systolic murmur was noticed with maximum intensity at the apex. The electrocardiogram (ECG) showed normal sinus rhythm (rate 150 bpm) with left-axis dewation, Q-waves in leads 1, aVL, V4 to V6, T-wave inversion in leads I and aVL, and ST elevation in lead aVL Echocardiography showed left ventricular hypertrophy, an insufficient mitral valve, and an ALCA from the pulmonary artery with retrograde flow. Cardiac catheterization confirmed the ALCA from the pulmonary artery and impaired contractility (eJection fraction 30%). A myocardial perfuslon tomoscintigraphy (99m TC Sestamibi) showed almost absent perfusion of the left ventricle and extended myocardial infarction. Captopril, an ACE inhibitor, was administered at a dose of 6 mg/day for left ventricular dysfunction in the presence of ischemic heart failure. Surgical treatment was planned 2 weeks later. Blood chemistry analysis showed normal values including the plasma potassium concentration (Table 1). The last dose of captopril was administered 8 hours before induction of anesthesia. The patient was premedicated with atropine, 0.1 mg, 1M. Anesthesia was induced with fentanyl, 10 Ixg/kg, and pancuronium, 0.4 mg. After