CONGRESS ABSTRACT

Case Report: A 52-year-old patient with a congenital heart defect, an atrial septal defect (ASD) surgically corrected at age 27, presents with newly diagnosed pulmonary hypertension. The patient's medical history includes previous unsuccessful catheter ablation attempts for supraventricular arrhythmias, including atrial fibrillation and atrioventricular nodal reentrant tachycardia. Recent clinical findings indicate pulmonary hypertension with a post-capillary component likely due to mitral regurgitation, as well as left ventricular systolic function at the lower limit of normal. Right heart catheterization suggests a borderline interatrial septal shunt (QP/QS ratio of 1.4). The most recent transthoracic echocardiography (TTE) performed in October 2024 reveals: an inferior vena cava at the upper limit of normal with reduced collapsibility, significant dilation of the right heart chambers and pulmonary artery, depressed right ventricular systolic function with both pressure and volume overload, a severely dilated left atrium, and a relatively small left ventricle with systolic-diastolic flattening of the interventricular septum. The mitral valve is thickened with posterior leaflet retraction, and color Doppler shows moderate mitral regurgitation and moderate-to-severe tricuspid regurgitation. There is dilation of the coronary sinus with systolic flow suggesting a possible unroofed coronary sinus. Elevated systolic pulmonary artery pressure is noted, but no pericardial effusion is present. Although TTE did not clearly show a shunt, transesophageal echocardiography (TEE) was not feasible due to technical difficulties. Given the suspected residual ASD, additional tests were conducted: bubble contrast echocardiography suggested a persistent left superior vena cava (LSVC) and unroofed coronary sinus (UCS), confirmed by a cardiac CT scan. The patient was referred to the Cardiac Surgery Unit for surgical correction. Discussion: By the fourth week of development, the coronary sinus forms from the left horn of the sinus venosus and the left common cardinal vein. A defect in the coronary sinus wall, often linked to a persistent left superior vena cava (PLSVC), results in an unroofed coronary sinus (UCS), causing abnormal communication between the heart chambers. UCS can be partial or complete and may occur with or without other anomalies. In the complete form, the roof is entirely absent, creating a larger connection between the coronary sinus and left atrium.