A tiny probe into the heart's hidden reserve could forecast who needs a transplant

This study looks at whether measuring the heart's 'reserve'—its ability to pump harder under stress—can predict how patients with advanced heart failure will do. Five patients with weak hearts (ejection fraction 40% or less) will be randomly assigned to receive the drug milrinone or no drug, while doctors use a catheter to measure pressures and blood flow inside the heart. The goal is to see if these measurements can forecast the need for major therapies like a heart pump or transplant, or the risk of death.