The study will begin once the participant arrives in the cardiothoracic intensive care unit (CTICU) after heart surgery for either heart transplant or LVAD placement. As is standard of care after these types of surgeries, the participant will arrive in the CTICU with a breathing tube already in place, receiving iNO, and connected to a breathing machine. The participant will be receiving relaxing medication in an intravenous line provided by the cardiac anesthesiologist and the CTICU physicians. The participant will be unaware of the study period while the participant is sedated. Data will be collected from the monitor screen connected to the participant's arterial and venous lines, and if placed, LVAD monitor. These data are: