Connecting the Dots: VF Arrest Secondary to Anomalous Origin of the Left Coronary Artery from the Pulmonary Artery Syndrome

Abstract

A 16-year-old male water polo player with no significant past history, was admitted to the current institution in cardiogenic shock following an out-of-hospital ventricular fibrillation arrest whilst swimming. The patient had return of spontaneous circulation following timely defibrillation for monomorphic left ventricular (LV) tachycardia. Transthoracic echocardiography (TTE) demonstrated a severely dilated LV, with severe global systolic dysfunction and an estimated LV ejection fraction (LVEF) of 30%. Troponin I assay was 5,760 ng/L. Intravenous methylprednisolone was commenced empirically for presumed myocarditis. Endomyocardial biopsy demonstrated mild non-specific cardiomyopathic changes and an increased number of blood vessels suggestive of a vascular malformation. Left ventricular systolic function improved, with repeat TTE a week after admission showing an LVEF of 50%. Cardiac magnetic resonance imaging showed a dilated LV with increased wall thickness and vascularity, primarily septal, and evidence of an old distal anterior myocardial infarct with wall thinning and transmural late gadolinium enhancement. Coronary angiography showed a large-calibre, ectatic right coronary artery, with retrograde filling of a highly abnormal left-sided system that could not be engaged. Computed tomography coronary angiogram was subsequently performed, demonstrating an anomalous left main coronary artery arising from the main pulmonary artery. There was a large dominant right coronary artery with multiple collaterals. This was a rare case of anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA syndrome), in which survival to adulthood was due to extensive collateralisation from the right coronary system. Silent myocardial ischaemia and infarct is not uncommon, as was seen in this patient. The patient underwent successful reimplantation of the left coronary artery to the aorta at a quaternary paediatric cardiothoracic referral centre.