Acute Decompensated Heart Failure in a Woman With Eisenmenger Syndrome: A Case Report

Eisenmenger syndrome (ES) is a rare and serious complication of congenital heart disease (CHD), characterized by intracardiac shunting, pulmonary hypertension, reversal of blood flow, and cyanosis. Management primarily involves pharmacotherapy to improve survival and prevent complications, with surgical or interventional closure considered in early-stage cases. We present a case of a 45-year-old woman, adopted at birth, who was diagnosed with ES around 10 years ago, which was confirmed through right heart catheterization, unbeknownst to the acute clinicians. She was admitted this time with features of acute decompensated heart failure. Her underlying condition, major aortopulmonary collateral arteries (MAPCA), had been intermittently monitored. Upon admission, she displayed classic heart failure symptoms, alongside elevated hematocrit and severely reduced but extremely well-tolerated oxygen saturation. Diagnostic evaluation, including echocardiography, confirmed pulmonary hypertension and right-to-left shunting, as the history was elusive to start with. This case highlights the diagnostic and management challenges associated with ES, particularly in patients with limited medical history. It emphasizes the importance of maintaining a high index of suspicion in the presence of chronic hypoxia and abnormal hematologic parameters. We discuss the role of echocardiography and adjunctive imaging in diagnosis, review the pathophysiologic mechanisms underlying ES, and outline current therapeutic strategies, including the use of endothelin receptor antagonists in the management of pulmonary arterial hypertension (PAH).