Participants in this study will undergo a series of adjustments to their pacemaker that will be made while they are undergoing routine, clinically indicated right heart catheterization in the outpatient setting after their left ventricular assist device (LVAD) surgery. Patients will undergo the study procedures while in the catheterization lab under controlled conditions. The study protocol involves increasing the rate that the pacemaker paces at. While the pacemaker is set to pace at different, increasing heart rates, pressures will be measured in the different chambers of the heart utilizing a special type of intravenous (IV) line called a pulmonary artery catheter. Several small blood samples will also be drawn from this venous catheter in order to measure oxygen levels in the blood. It will take approximately 30 minutes to perform the study, and when it is completed, the pacemaker will be returned to its original settings.

This study is an early feasibility study which typically consist of evaluating innovative devices or innovative uses of approved devices. The purpose of this study is to see if an investigational device called preCARDIA Intermittent Balloon Device can limit fluid overload in congested patients with advanced heart failure. This investigational device is a catheter which has been approved by the U.S. Food and Drug Administration (FDA) to occlude large vessels but not for the treatment of advanced heart failure. Currently, there are no device-based approaches that are FDA-approved for advanced heart failure. This study will help find out if this device-based approach can improve symptoms and heart function in congested patients with advanced heart failure

This research study aims to determine a less invasive way to assess heart function by taking measurements of the heart while subjects are performing an exercise cardiac MRI. Subjects will undergo two exercise phases and MRI measurements will be taken after each exercise phase. These measurements will be compared to available clinical data (including demographic, hemodynamic, radiologic, and functional) and future outcome data.

Elevated pressures in the heart can represent a severe medical condition known as pulmonary hypertension. This can result in chronic right heart failure. An abnormal increase in this pressure during exercise may be represent an early stage of vascular lung disease. This study will investigate the prognostic implications of the measured pressures obtained during exercise while undergoing a right heart catheterization procedure based on a large scale multi-center approach by using retrospective and prospective analysis of hemodynamic data.