Congenital heart diseases are structural abnormalities of the heart with functional repercussions on the patient's hemodynamics. At the time of diagnosis, most patients are in childhood, and the clinical course exhibits a wide spectrum of severity, ranging from mild conditions that do not affect the quality of life to severe presentations that may lead to death. Under this concept, we present the case of a 45-year-old patient who was diagnosed in childhood with a ventricular septal defect for which he did not receive any treatment or intervention. Despite this, he remained asymptomatic until his fourth decade, when he developed moderate exertional dyspnea associated with chest pain relieved by rest. On physical examination, a holosystolic murmur radiating to all auscultatory areas throughout the cardiac cycle was observed. Diagnostic tests such as echocardiography confirmed the presence of a pseudomembranous ventricular septal defect associated with left ventricular remodeling and hypokinesia. A chest X-ray revealed a normal cardiothoracic ratio, and a computed tomography angiogram evidenced an obstruction in the right ventricular outflow tract attributed to subinfundibular hypertrophy. Cardiac catheterization ruled out ischemic etiology. These findings led the cardiothoracic surgical team to recommend surgical intervention, which consisted of resection of the fibromuscular ridge in the right ventricular outflow tract and repair of the ventricular septal defect. Post-surgical follow-up echocardiography revealed normal hemodynamic values. This case highlights the importance of the early detection and treatment of congenital heart diseases as well as the significance of a comprehensive diagnostic approach for each patient.