After informed consent is obtained from the patient, the blood samples will be obtained either during a procedure from access lines inserted for the procedure or they will be drawn when other ordered lab work is done at specific time points during the study. Tissue samples will be obtained at the time of LVAD implantation by keeping the part of the left ventricular apex that the surgeon is removing in order to place the inflow cannula of the LVAD. No extra tissue sample, other than the tissue that has to be removed as a part of a standard LVAD, will be collected.