Dilated Coronary Sinus Causing Left Ventricular Inflow Obstruction: Decision on surgical intervention.

Objectives: A significantly dilated coronary sinus causing left ventricular inflow obstruction presents a challenging dilemma during surgical repair of associated anomalies. We report a 5-month-old male infant was referred to a national heart centre in Muscat, Oman, in 2023 with a persistent left superior caval vein, dilated coronary sinus, partially anomalous pulmonary venous drainage and a large atrial septal defect, resulting in left ventricular inflow obstruction and low cardiac output. The dilated coronary sinus intensified a left-to-right shunt, leading to left ventricular underfilling and early heart failure symptoms. Although surgical correction was planned, direct intervention on the coronary sinus was deferred after intraoperative assessment, supported by virtual dissection of 2-dimensional computed tomography datasets. This non-invasive imaging provided detailed anatomical understanding, comparable to conventional dissection and guided the decision to leave the dilated coronary sinus untouched. Post-operative outcomes showed improved left ventricular filling and resolution of low cardiac output, supporting the chosen strategy. This case highlights the role of virtual dissection in complex surgical planning and decision-making.