A casually observed case of complex congenital cardiopathy in an adult marked by ECG LAE, and paradoxical movement of the interventricular septum when examined echocardiographically is reported. Haemodynamic investigation established the persistence of a left vena cava superiore draining into the coronary sinus, pulmonary stenosis with a 55 mmHg transvalvular gradient, and a small PDA with left-to-right shunt equal to 20% of the pulmonary capacity. The case is presented on account of the infrequent association of these defects, the unusual ECG LAE, and above all on account of the echocardiographic picture of paradoxical movement of the IVS in the presence of right ventricle overloading.