Abstract Body (Do not enter title and authors here): Clinical Course
A 62-year-old male with a history of coronary artery disease presented with one month of intermittent chest pain which progressed to severe persistent chest pain. Initial vitals: blood pressure 78/50 mmHg, pulse rate 100 bpm, and oxygen saturation 94%. Examination revealed bilateral pulmonary crackles and grade 4/6 holosystolic murmur at the cardiac apex. The electrocardiogram suggested inferolateral STEMI, and the patient was taken for coronary catheterization, and intubated due to hypoxic respiratory failure from pulmonary edema. Impella CP was placed for hemodynamic support. Catheterization revealed 100% occlusion of the mid-left circumflex (LCx), 75% occlusion of the distal left anterior descending artery, and chronic total occlusion of the right coronary artery. Two drug eluting stents were deployed to the mid-LCx lesion, achieving TIMI 3 flow. Emergent transesophageal echocardiogram (TEE) revealed hyperdynamic LV systolic function, severe mitral regurgitation (MR) with severe MV flail involving the posterior leaflet (Figure 1a-c). The posterolateral papillary muscle head was ruptured (Figure 1d).
Despite Impella CP and pressor support with norepinephrine at 4 mcg/min, cardiogenic shock persisted; mixed venous oxygen saturation (MVO2) was 47%, pulmonary artery pulsatility index (PAPi) was 1.4, cardiac power output (CPO) was 0.61 W. Upgrading to Impella 5.5 improved MVO2 to 68%, PAPi to 2.5, and CPO to 1.16 W. He underwent coronary artery bypass grafting (CABG) and surgical mitral valve replacement (MVR) with a bioprosthetic valve. Following surgical MVR, TTE revealed an appropriately functioning bioprosthetic valve, and LV ejection fraction of 35-40% with multiple areas of hypokinesis. Despite appropriate prosthetic valve function, the patient suffered pulmonary hemorrhage, septic shock, and expired on hospital day 10.

Discussion
Papillary muscle rupture is an uncommon complication of acute myocardial infarction but is often fatal. In our patient, TTE was imperative in timely recognition and management of acute MR and preparation for MVR. Impella mechanical circulatory support was used as a bridge to surgical intervention with MVR and temporized the patient’s cardiogenic shock. Despite its importance, literature on Impella use in this condition is scarce. While the patient ultimately expired, prompt use of echocardiography and Impella were important to bridge the gap to MVR.