An Unusual Presentation of Eisenmenger Syndrome in a Middle-Aged Woman Without Known Cardiac History.

Eisenmenger syndrome (ES) is a severe cardiac complication that arises from an untreated congenital cardiac defect, leading to the reversal of shunt flow, pulmonary hypertension, and cyanosis. This uncommon complication most frequently arises from small ventricular septal defects that are undiagnosed due to a lack of symptoms. However, it may arise from the reversal of any left-to-right cardiac shunt. In the following report, we present a case of acute-onset ES in a 52-year-old woman with no past cardiac history. The patient presented to the emergency department with a clinical presentation consistent with likely pulmonary embolism; however, after extensive work-up, this etiology of respiratory failure was deemed incorrect. After rapid respiratory decline requiring mechanical ventilation, the medical team performed two transthoracic echocardiograms (one with agitated saline study), one transesophageal echocardiogram, and a right cardiac catheterization on the patient. This work-up revealed pulmonary hypertension, right heart failure, and an atrial septal defect. Given these findings, the work-up was suggestive of ES secondary to an atrial septal defect shunt reversal. Because of the complexity of treatment, the patient was transferred via air to a university tertiary medical institution for extracorporeal membrane oxygenation along with other advanced treatments. This case provides a framework for the clinical presentation and treatment of this life-threatening disease. We hope that this information will help providers understand the clinical presentation, work-up, treatment, and prognosis of patients with Eisenmenger syndrome.