Recurrent Syncope and Sudden Cardiac Death due to Anomalous Origin of the Right Coronary Artery From the Pulmonary Artery (ARCAPA): A Case Report

Abstract

Introduction: Congenital coronary artery anomalies are uncommon but clinically significant conditions associated with myocardial ischemia, malignant ventricular arrhythmias, and sudden cardiac death, particularly in young individuals. Among these anomalies, anomalous origin of the right coronary artery from the pulmonary artery (ARCAPA) is exceptionally rare, with a reported prevalence of approximately 0.002%. Although ARCAPA may remain clinically silent for many years due to collateral circulation from the left coronary system, it carries a persistent risk of myocardial ischemia caused by a coronary steal phenomenon and may result in sudden cardiac death. Case Presentation: We report the case of a 19-year-old Somali male with no prior medical history who presented with a several-month history of recurrent syncope occurring both at rest and during exertion, without preceding chest pain, palpitations, dyspnea, seizure-like activity, or prodromal symptoms. He presented following a prolonged syncopal episode and was found to be hemodynamically unstable, with a blood pressure of 86/54 mmHg and sinus tachycardia. Initial laboratory investigations, including complete blood count, renal function, serum electrolytes, coagulation profile, and cardiac biomarkers, were within normal limits. Electrocardiography demonstrated diffuse ST-segment depression in the inferolateral leads with reciprocal ST-segment elevation in lead aVR, raising concern for global subendocardial ischemia. Transthoracic echocardiography revealed preserved left ventricular systolic function, with an ejection fraction of 65%, a mildly dilated main pulmonary artery, and mild pulmonary regurgitation. Due to the unavailability of coronary computed tomography angiography, urgent invasive coronary angiography was performed approximately 4 hours after presentation. Angiography revealed anomalous origin of the right coronary artery from the pulmonary artery with retrograde flow into the pulmonary trunk, consistent with a significant coronary steal phenomenon. No obstructive coronary artery disease was identified. Approximately 30 minutes after angiography, the patient developed sudden hemodynamic collapse and progressed to cardiac arrest. Despite prolonged advanced cardiopulmonary resuscitation, return of spontaneous circulation was not achieved. The presumed cause of death was malignant ventricular arrhythmia secondary to myocardial ischemia related to ARCAPA; however, the exact mechanism could not be definitively established. Discussion: This case highlights the potential for rapid fatal deterioration in ARCAPA despite preserved ventricular systolic function. Recurrent syncope and ischemic electrocardiographic abnormalities should be recognized as high-risk features. The electrocardiographic pattern observed may reflect diffuse myocardial ischemia due to coronary steal rather than atherosclerotic coronary artery disease. Conclusion: ARCAPA should be considered in young patients presenting with unexplained recurrent syncope and high-risk electrocardiographic findings. Early recognition, appropriate use of multimodality imaging, close monitoring, and prompt surgical referral are essential to prevent catastrophic outcomes.