What Is Acute Heart Failure? Here’s What You Need to Know Lisa Marie Conklin Replay Video What is heart failure? If ever there were a prize awarded for "most misleading name given to a medical condition," heart failure would win hands down. "Heart failure (also called congestive heart failure) is a terrible name which suggests the heart has stopped working completely," says Anthony Steimle, MD, a cardiologist and assistant physician in chief of cardiovascular services at Kaiser Permanente in Santa Clara, California. In fact, the heart has not stopped working. The heart muscle, however, is damaged. Specifically, the heart can become weak and unable to pump blood (systolic heart failure), or the heart can become stiff and unable to fill with blood adequately (diastolic heart failure).