Cardiac Arrest Associated with Both an Anomalous Left Coronary Artery and KCNE1 Polymorphism.

A 14-year-old boy collapsed suddenly after a basketball game and was transported to our hospital after recovering from ventricular fibrillation by an automated external defibrillator. He had experienced loss of consciousness twice and has been examined for suspected long-QT syndrome at another hospital. The 12-lead electrocardiogram on admission revealed a prolonged QTc interval of 480 milliseconds. After the patient recovered without any sequelae, computed tomography revealed an anomalous left coronary artery arising from the opposite sinus of Valsalva and coursing between the aorta and the pulmonary artery. Furthermore, genetic testing identified a KCNE1-D85N abnormality. An anomalous coronary artery is one of the major causes of sudden death in young people; therefore, surgical revascularization is recommended for left coronary arteries arising from the contralateral sinus and coursing between the aorta and the pulmonary artery, regardless of myocardial ischemia. Transient myocardial ischemia may have exaggerated the instability from the arrhythmic substrate, even though KCNE1-D85N abnormalities alone are not thought to cause fatal arrhythmias. Besides routine electrocardiography, further examinations, including imaging and genetic testing, can characterize the pathophysiology of fatal cardiac disease.