TITLE:
Intermediate Atrioventricular Septal Defect with Severe Pulmonary Arterial Hypertension Diagnosed at Age 58: A Rare Case from Central Africa
AUTHORS:
Solange Flore Mongo Ngamami, Rog Patern Bakekolo, Brigitte Esther Ovaga, Kivié Mou-Moué Ngolo-Letomo, Franck Yannis Kouikani, Jean-Romain Bianza, Bertrand Fikahem Ellenga-Mbolla
KEYWORDS:
Atrioventricular Septal Defect, Pulmonary Arterial Hypertension, Adult Congenital Heart Disease, Late Diagnosis, Echocardiography, Sub-Saharan Africa, Republic of Congo
JOURNAL NAME:
World Journal of Cardiovascular Diseases,
Vol.16 No.2,
February
28,
2026
ABSTRACT: Background: Intermediate atrioventricular septal defect (AVSD) rarely presents in late adulthood, as most untreated patients develop irreversible pulmonary arterial hypertension (PAH) and die in early childhood. Survival beyond infancy without surgical correction is exceptional and typically associated with restrictive ventricular components that protect the pulmonary vasculature. Case Presentation: We report a 58-year-old mechanic from the Republic of Congo with facial dysmorphism suggestive of Down syndrome who presented with progressive dyspnea and right heart failure. Clinical examination revealed generalized cyanosis (oxygen saturation 88% on room air), New York Heart Association (NYHA) class III dyspnea, bilateral lower extremity edema, and ascites. Cardiovascular examination demonstrated a loud systolic murmur at the pulmonary area and an accentuated second heart sound. Chest radiography showed severe cardiomegaly with pulmonary artery prominence. Electrocardiography revealed right ventricular hypertrophy with ventricular ectopy. Transthoracic echocardiography confirmed intermediate AVSD with a large ostium primum atrial septal defect (34 mm) showing significant left-to-right shunting (Qp/Qs > 1.5), a restrictive inlet ventricular septal defect nearly obliterated by common atrioventricular valve attachments, severe bilateral atrioventricular valve regurgitation, and severe PAH (systolic pulmonary artery pressure 58 mmHg). N-terminal pro-B-type natriuretic peptide was markedly elevated at 340,000 pg/mL. The patient received palliative medical therapy with diuretics and aldosterone antagonists, achieving symptomatic improvement from NYHA class III to II. Surgical correction was not feasible due to established PAH and limited local cardiovascular surgical resources. Conclusion: This case represents, to our knowledge, the first documented intermediate AVSD diagnosed in late adulthood in the Republic of Congo. The restrictive ventricular component provided relative pulmonary protection, enabling prolonged survival despite the absence of surgical intervention. This case highlights critical challenges in managing complex congenital heart disease in resource-limited settings and underscores the importance of prenatal screening and early surgical intervention programs in sub-Saharan Africa.