C63-24 A Pressure Shift With Deadly Consequences

Abstract Introduction Right ventricular (RV) infarction is an uncommon but serious complication of inferior wall myocardial infarction (IWMI), often causing severe hemodynamic compromise and increased mortality. The American Heart Association identifies RV involvement in IWMI as an independent predictor of in-hospital death. Acute RV dysfunction can elevate right-sided pressures, reopening a patent foramen ovale (PFO) and producing right-to-left shunting with refractory hypoxemia. We present a case of recurrent right coronary artery thrombosis resulting in RV infarction, PFO-mediated shunting, and rapid progression to multi-organ failure despite intervention. Case Presentation A 72-year-old woman with diabetes mellitus presented with severe retrosternal chest pain radiating to the jaw and left arm, preceded by intermittent exertional discomfort for two months. She was initially hemodynamically stable. Laboratory evaluation showed creatinine 1.4 mg/dL, BNP 4,500 pg/mL, and high-sensitivity troponin I 3,056 ng/L (down-trending). ECG and chest radiography were unremarkable. Coronary angiography demonstrated complete occlusion of the proximal right coronary artery (RCA) distal to the sinus node branch, with distal filling via left-to-right collaterals. Aspiration thrombectomy was performed, followed by tandem stent placement, restoring flow. Dual antiplatelet therapy with aspirin and ticagrelor was initiated. Echocardiography showed preserved left ventricular ejection fraction (LVEF 55%) with mild mitral and tricuspid regurgitation. On hospital day two, she developed sudden pallor, diaphoresis, and profound bradycardia (heart rate in the 30s) while straining on the toilet. ECG confirmed complete atrioventricular block. Emergent catheterization revealed acute in-stent thrombosis; additional stents were placed in the proximal and distal RCA extending into the posterolateral branch, and a temporary transvenous pacemaker was inserted. She subsequently developed acute hypoxemic respiratory failure refractory to BiPAP and mechanical ventilation, requiring vasopressor support. Repeat echocardiography showed new LV dysfunction (EF 35-40%), severe RV hypokinesis, and a PFO with right-to-left shunting consistent with elevated right atrial pressures secondary to RV infarction. Her condition rapidly deteriorated, resulting in multi-organ failure; goals of care were transitioned, and she died hours later. Discussion RV infarction complicates a significant subset of IWMI and can precipitate hemodynamic collapse when right-sided pressures exceed left-sided pressures, promoting PFO-mediated shunting and refractory hypoxemia. In patients with suspected RV involvement who demonstrate persistent hypoxemia despite oxygenation and ventilation, early echocardiographic assessment for intracardiac shunt is essential. This case emphasizes the importance of recognizing RV failure physiology and considering early mechanical support strategies when revascularization alone does not restore adequate RV function. Color Doppler on TTE demonstrating right to left flow across a PFO. This abstract is funded by: None