Obstructive Hypertrophic Cardiomyopathy and Interarterial Anomalous Aortic Origin of the Right Coronary Artery (AAORCA) Presenting With Syncope: Multimodal Diagnostic Assessment and Individualized Management

The coexistence of obstructive hypertrophic cardiomyopathy (oHCM) and anomalous aortic origin of the right coronary artery (AAORCA) with an interarterial course is exceptionally rare and poses a significant diagnostic and therapeutic challenge, particularly in patients presenting with syncope. We report the case of a 63-year-old man referred for evaluation of a sudden syncopal episode that occurred at rest while he was seated on an airplane, followed by a fall on standing. Transthoracic echocardiography revealed asymmetric septal hypertrophy, systolic anterior motion of the mitral valve. and a marked dynamic obstruction of the left ventricular outflow tract (LVOT), with a peak gradient of 60 mmHg at rest and 123 mmHg during the Valsalva maneuver. Coronary CT angiography identified an anomalous origin of the right coronary artery from the left coronary sinus, with a proximal interarterial aortopulmonary course and a slit-like ostio-proximal segment, without intramural extension or significant stenosis. Cardiac MRI showed asymmetric septal hypertrophy with focal late gadolinium enhancement of the basal interventricular septum, consistent with myocardial fibrosis. The European Society of Cardiology (ESC) five-year sudden cardiac death risk score was 4.88%. After multidisciplinary discussion, management included primary-prevention implantation of an implantable cardioverter-defibrillator, conservative management of the coronary anomaly, and initiation of mavacamten. Clinical and hemodynamic evolution was favorable, with no recurrence of syncope, no sustained ventricular arrhythmias on an implantable cardioverter-defibrillator (ICD) interrogation, and a marked reduction in the peak gradient of dynamic obstruction to 5 mmHg at rest and 7 mmHg after Valsalva at six-month follow-up. This case illustrates the value of multimodal diagnostic evaluation and individualized management in patients with coexisting obstructive HCM and interarterial AAORCA. In this context, the integration of echocardiographic, computed tomography, magnetic resonance imaging, and clinical risk data can help guide both arrhythmic prevention and therapeutic decision-making.