RESUMO
A previously asymptomatic 15-year-old boy was treated at our institution after an episode of chest pain, palpitation, and syncope while playing in a high school soccer game. The patient's resting electrocardiogram was normal. A transthoracic echocardiogram showed an anomalous left main coronary artery originating from the right sinus of Valsalva. Contrast-enhanced multidetector computed tomography demonstrated clearly that the anomalous vessel coursed between the aorta and the pulmonary trunk (interarterial subtype). Treadmill testing registered several nonsustained polymorphic ventricular tachycardias and transmural myocardial ischaemia in the early recovery phase (ST-elevation up to 5mm in CM5 and V2 leads). The patient underwent bypass grafting. One year later, he remains asymptomatic, and new treadmill tests have been normal. In this patient, severe transmural myocardial ischaemia was detected, possibly due to collapse or vasospasm of the anomalous vessel, triggering life-threatening ventricular arrhythmias.