Discussion
The Discovery of dilated coronary sinus on echocardiography may further lead to the exclusion of PLSVC. Non-invasive transthoracic echocardiography study by agitated saline contrast can be easily performed to confirm the related venous anomaly. Sub-aortic membrane with PLSVC is usually presented with mild symptoms or asymptomatic in younger age or in previously healthy adults [10]. In our case, the patient with both persistence SVCs and subaortic membrane was presented with mild symptoms. The coexistence of subaortic membrane and persistence of both superior vena cava (SVCs) is a very rare condition and only few cases are reported in the literature. A prevalence study by Oliver et al. demonstrated that mild aortic regurgitation is common in adult and non-progressive over time [11]. Some comprehensive study evaluated that progression of subaortic stenosis in adults did not coexistence with any case of an associated isolated PLSVC. Most patients with subaortic membrane are at risk for faster progression and should be monitored cautiously [10]. Therefore, most adult patients with PLSVC and subaortic membrane should be reassured by symptomatic management.