Clinical Hemodynamic Study of Balloon Counterpulsation in Advanced Heart Failure

Inclusion Criteria: * Male or females between 18-75 years of age * NYHA Class III-IV heart failure at the time of MEGA deployment * Stage C-D systolic heart failure * Non-ischemic cardiomyopathy * Preserved right ventricular function defined by 2D-echocardiography * Clinically indicated left and right heart catheterization and MEGA-IABP placement * Clinically indicated MEGA-IABP support for 12 hours minimum Exclusion Criteria: * Ischemic cardiomyopathy * Active myocardial ischemia or acute coronary syndrome * Severe peripheral vascular disease * Severe aortic or mitral valve insufficiency * Severe aortic or mitral valve stenosis * Right ventricular failure * Inability to tolerate left and right heart catheterization * Severe hemodynamic instability defined as a systolic BP \<80mmHg despite vasopressor/inotropic support * Sustained ventricular tachycardia (\>10 beats) within 24 hours and/or ventricular fibrillation within 24 hours * Pacemaker dependent rhythm * Left ventricular thrombus * Rapid atrial fibrillation (HR\>120 bpm) * Unable to provide informed consent * Pregnancy