The CircuLite Synergy pump is a new minimally-invasive partial support left ventricular assist device (LVAD) that pumps blood from the left atrium to the right subclavian artery. Ex vivo pilot data suggests that the Synergy pump induces structural reverse remodelling, which proposes the Synergy device as a new disease-modifying therapy. We will assess whether the Synergy pump facilitates functional, structural and molecular LV reverse remodelling in vivo; assess how this can be determined and predicted by analysis of circulating micro RNA profiles and specific echocardiographic parameters; and evaluate the haematological abnormalities associated with this new LVAD.