For decades, physicians have known that about half of all patients with heart failure appear to have hearts that contract normally—a syndrome now known as heart failure with a preserved ejection fraction (or HFpEF, pronounced hef-pef). This type of heart failure was first seen primarily in slim, elderly women with high blood pressures and thicker heart muscle. But as the incidence of obesity and diabetes has increased, many patients with HFpEF are now found to be severely obese with blood pressures not as high and heart muscle not as thick as seen in previous patients.