A variety of diseases and events-heart attack, hypertension, diabetes and heart infections among them-can cause injury to the heart muscle, rendering it unable to work properly. This is called heart failure. Heart failure is very common-more than 5 million adults in the United States have it. Yet many people are unaware there are two very different forms. One form, called heart failure with preserved ejection fraction (HFpEF) or diastolic heart failure, affects more women than men.