Eisenmenger syndrome secondary to atrial septal defect: heart failure and severe pulmonary hypertension – a challenging clinical case

Abstract

Eisenmenger syndrome represents the most advanced form of pulmonary arterial hypertension associated with congenital heart disease and is characterized by markedly elevated pulmonary vascular resistance, with bidirectional or reversed shunting at the atrial, ventricular, or arterial level. Its development is related to large, uncorrected defects of long-standing duration; the risk is higher in post-tricuspid and aortopulmonary shunts, whereas in pre-tricuspid defects, such as atrial septal defects, progression is typically later and less frequent. Atrial septal defect is a usually acyanotic congenital heart disease and represents the most commonly diagnosed congenital cardiac lesion in adulthood; the ostium secundum subtype accounts for the majority of cases. In large pre-tricuspid defects, progression to advanced pulmonary vascular disease has been estimated at approximately 5–10%. ^1-4 We report the case of a 53-year-old woman with a history of peripheral cyanosis and lower extremity edema since early adulthood, without prior cardiologic diagnosis, who presented with progressive dyspnea, orthopnea, bilateral edema, ascites, and syncope in the setting of decompensated heart failure. Initial studies revealed hypoxemia and elevated NT-proBNP levels, as well as cardiomegaly and central pulmonary vascular prominence on chest radiography. The electrocardiogram showed right axis deviation, incomplete right bundle branch block, and signs of right heart chamber overload. Chest computed tomography demonstrated cardiomegaly predominantly involving the right chambers and dilation of the main pulmonary artery. Transthoracic echocardiography identified a 1.5 cm ostium secundum atrial septal defect, with a Qp/Qs ratio of 2.4, severe right chamber dilation, and severe pulmonary hypertension estimated by Doppler (PASP 75 mmHg). This case illustrates the late presentation of an undiagnosed atrial septal defect complicated by severe pulmonary hypertension and decompensated right heart failure, with a clinical course suggestive of Eisenmenger physiology. Its relevance lies in demonstrating how a classically acyanotic congenital heart disease may remain unrecognized into adulthood and present at advanced stages, underscoring the need to critically integrate clinical evolution and multimodal findings to guide diagnosis and prognosis.