BACKGROUND: The outlook for ambulatory patients with advanced heart failure (HF) and the appropriate timing for left ventricular assist device (LVAD) or transplant remain uncertain. The aim of this study was to better understand disease trajectory and rates of progression to subsequent LVAD therapy and transplant in ambulatory advanced HF. METHODS: Patients with advanced HF who were New York Heart Association (NYHA) Class III or IV and Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Profiles 4 to 7, despite optimal medical therapy (without inotropic therapy), were enrolled across 11 centers and followed for the end-points of survival, transplantation, LVAD placement, and health-related quality of life. A secondary intention-to-treat survival analysis compared outcomes for MedaMACS patients with a matched group of Profile 4 to 7 patients with LVADs from the INTERMACS registry. RESULTS: Between May 2013 and October 2015, 161 patients were enrolled with INTERMACS Profiles 4 (12%), 5 (32%), 6 (49%), and 7 (7%). By 2 years after enrollment, 75 (47%) patients had reached a primary end-point with 39 (24%) deaths, 17 (11%) undergoing LVAD implantation, and 19 (12%) receiving a transplant. Compared with 1,753 patients with Profiles 4 to 7 receiving LVAD therapy, there was no overall difference in intention-to-treat survival between medical and LVAD therapy, but survival with LVAD therapy was superior to medical therapy among Profile 4 and 5 patients (p = 0.0092). Baseline health-related quality of life was lower among patients receiving a LVAD than those enrolled on continuing oral medical therapy, but increased after 1 year for survivors in both cohorts. CONCLUSIONS: Ambulatory patients with advanced HF are at high risk for poor outcomes, with only 53% alive on medical therapy after 2 years of follow-up. Survival was similar for medical and LVAD therapy in the overall cohort, which included the lower severity Profiles 6 and 7, but survival was better with LVAD therapy among patients in Profiles 4 and 5. Given the poor outcomes in this group of advanced HF patients, timely consideration of transplant and LVAD is of critical importance.