Additional Study Information: This is a Prospective, multicenter, randomized, parallel-controlled, open-label two-arm trial with an adaptive design that will randomize about 1252 subjects at approximately 120 US and international centers. The study is looking to see if a device called the Impella device will improve the way the heart works as well as if health is improved as compared to what is currently used for patients with reduced left-sided heart function. Participants will be assigned by the flip of a coin to receive the Impella device, or assigned to receive standard of care treatment. Participants will have a follow-up visit at 30-days after discharge from the hospital, a follow-up visit at 6 months, 1 year, 2 years, and 3 years after the procedure.