Persistent Unexplained Desaturation After Myocardial Infarction

Hypoxemia following myocardial infarction (MI) is frequently attributed to left ventricular dysfunction, valvular regurgitation, or pulmonary causes. However, intracardiac shunting, such as a patent foramen ovale (PFO), may also play a critical role in refractory cases. We present a 67-year-old woman with inferior wall MI and persistent desaturation despite successful revascularization and optimized medical management. Saline contrast echocardiography revealed a PFO with a right-to-left shunt. Conservative management with supportive care and improvement of right ventricular (RV) function led to the resolution of symptoms, underscoring the importance of comprehensive evaluation for unexplained hypoxemia in MI patients.