A Case of Refractory Hypoxemia Secondary to Intracardiac Shunt Diagnosed in the Catheterization Laboratory

An 80 -year -old female patient presented to our institution with an inferior ST -elevation myocardial infarction, cerebral hypoxia, and refractory hypoxemia, without signs of pulmonary congestion. Invasive right -sided heart catheterization facilitated the diagnosis of a right -to -left (R -L) cardiac shunt. An unidentified R -L cardiac shunt is a rare cause of refractory hypoxemia in patients with a preexisting, unknown atrial septal defect or patent foramen ovale, particularly in cases presenting with right ventricular myocardial infarction (RVMI). A prompt diagnosis of this condition can guide the management of these patients and prevent the implementation of deleterious treatment measures. Herein, we detail the initial presentation, investigations, management, and clinical course of this patient.