Heart muscle weakness, also known as cardiomyopathy, is a condition where the heart muscle becomes weakened and is unable to pump blood efficiently. This can lead to heart failure and other complications. Causes of cardiomyopathy include genetic factors, high blood pressure, heart valve problems, and certain infections. Symptoms may include fatigue, shortness of breath, swelling in the legs, and irregular heartbeats. Treatment options vary depending on the severity and cause but may include medications, lifestyle changes, or surgical interventions to improve heart function.