Physiology of Unloading VA ECMO Trial

The goal of this clinical trial is to compare the use of veno-arterial extracorporeal membrane oxygenation (VA ECMO) with and without left ventricular (LV) unloading in patients being treated for cardiogenic shock (CS). The main aims of the study are: 1. To determine the physiologic effects on cardiopulmonary congestion of adding LV unloading to VA ECMO 2. To determine the effects on myocardial function of adding LV unloading to ECMO 3. To test the effects on myocardial recovery of adding LV unloading to VA ECMO Participants who are being treated with VA ECMO will be randomized to receive or not receive LV unloading in the form of an intra-aortic balloon pump (IABP). Over the course of the study, the investigators will obtain measurements via lab work, echocardiography, and pulmonary artery catheter that will allow comparison of the two groups.