Drinking alcohol regularly and heavily for many years can weaken the muscle walls of the heart. The weakened muscles then stretch, which causes the heart to become larger. A large, weakened heart cannot pump blood through the body normally. Such symptoms as fatigue, shortness of breath, and leg swelling result. Doctors call this problem alcohol-related heart failure, or alcoholic cardiomyopathy. Drinking small to moderate amounts of alcohol, on the other hand, may help prevent heart attacks. Heart attacks occur when blood flow through the arteries to the heart (the coronary arteries) is blocked for a time long enough to damage or kill a portion of heart muscle. People who survive heart attacks may develop heart failure because of weakened or dead heart muscle. Thus, it is thought that drinking small to moderate amounts may indirectly prevent heart failure, but regular heavy drinking causes heart failure. Sorting out these tricky relationships between amounts of alcohol use and risk for heart failure is difficult.