A five-year-old boy with recurring tonsillitis and sleep apnea was admitted for tonsillectomy and tympanic membrane tubing. He presented with a history of bronchial asthma and hereditary spherocytosis without obvious cardiac failure symptoms. Anesthetic agents for induction included nitrous oxide, oxygen, and sevoflurane. Because oxygen saturation decreased immediately to 90%, tracheal intubation was performed. The patient began to wheeze. Sevoflurane concentration was increased but cardiac murmur (gallop), cold limbs and jugular vein distension were noted. Acute cardiac failure was diagnosed following a chest X-ray and cardiac echo showing an enlarged heart, CTR of 80%, left ventricular dilation, and contractile failure. Tympanic membrane tubing only was performed. Sevoflurane was discontinued and the patient was treated for the cardiac failure under an ICU oxygen tent. The patient was discharged when his general condition improved. He showed elevated levels of viral antibodies, suggesting myocarditis. Later he was treated for dilating cardiomyopathy before undergoing a heart transplant.