Congenital left main coronary artery atresia presenting as syncope and generalized seizure during exercise in a 13-year-old boy.

We report the case of a 13-year-old boy who, while running in a school gymnasium, experienced sudden syncope and seizure. CPR was started immediately, and an automated external defibrillator (AED) was attached, but shock was not induced. He was referred to our hospital for loss of consciousness and intermittent general tonic-clonic seizure. A 12-lead electrocardiogram showed normal sinus rhythm and no ST-T wave abnormalities. Echocardiography showed normal structural heart and normal cardiac function. On the second day of hospitalization, AED electrocardiogram showed complete atrioventricular (AV) block at syncope and seizure. After the patient recovered from this neurological state, we performed the treadmill exercise test, and it did not show ST-T wave abnormalities or AV block, and he did not complain of chest pain. Coronary angiography showed atresia of the left main trunk and the collateral vessel from the right coronary artery connected to the left coronary artery. He was diagnosed with congenital left main coronary artery atresia. We began administration of calcium antagonist and aspirin to prevent a coronary artery spasm and then performed a coronary artery bypass graft (CABG) to prevent sudden cardiac death. After CABG, he has had no syncope episodes at rest or during light exercise. .