In the United States, the most common identifiable cause of dilated cardiomyopathy is extensive coronary artery disease. Such coronary artery disease results in an inadequate blood supply to the heart muscle, which leads to permanent injury and death of heart muscle. As a result, the heart cannot pump as forcefully. The dead heart muscle is replaced by fibrous (scar) tissue. The remaining uninjured heart muscle then stretches and thickens (hypertrophies) to compensate for the lost pumping action. The more the heart muscle is stretched, the more forcefully it contracts or pumps but only up to a point. After that point, the stretching and thickening do not adequately compensate, and dilated cardiomyopathy with heart failure develops which leads to permanent injury and death of heart muscle. As a result, the heart cannot pump as forcefully. The dead heart muscle is replaced by fibrous (scar) tissue. The remaining uninjured heart muscle then stretches and thickens (hypertrophies) to compensate for the lost pumping action. The more the heart muscle is stretched, the more permanent injury and death of heart muscle. As a result, the heart cannot pump as forcefully. The dead heart muscle is replaced by fibrous (scar) tissue. The remaining uninjured heart muscle then stretches and the most common identifiable cause is extensive artery disease to compensate for the lost pumping action.