The HeartAssist5 is a new axial-flow left ventricular assist device (LVAD) that has been engineered to provide greater pulsatility and improved hemocompatibility. This LVAD's pressure and flow characteristics during clinical use have not been previously reported. After HeartAssist5 implantation, we performed a ramp study with simultaneous right heart catheterization. High speeds were required to significantly reduce the filling pressures and normalize cardiac output (CO). CO was consistently lower than reported flow from the flow probe, but there was a strong correlation between changes in CO and changes in pump flow (R of 0.80). This assessment of intracardiac hemodynamics during changes in HeartAssist5 speed provides important clinical information about pump physiology beyond what can be evaluated in preclinical studies.