Heart muscle damage of any type weakens the heart muscle and can lead to heart failure. The most common causes of heart muscle damage (often called cardiomyopathy) in the U.S. are listed below.
- Atherosclerosis (coronary artery disease, CAD). In many people with heart failure, the arteries that supply the heart with blood are narrowed or clogged. This condition is called atherosclerosis, or coronary artery disease (CAD). Coronary artery disease reduces the amount of oxygen your heart receives and weakens the muscle. It can also cause a heart attack (called myocardial infarction, or MI) that leaves scar tissue on your heart. Unlike normal heart muscle, scar tissue doesn’t contract so your heart may pump less effectively. Heart muscle damage that results from coronary artery disease is typically called ischemic cardiomyopathy.
- High blood pressure (hypertension). Long-term, poorly controlled high blood pressure makes your heart work harder to pump blood through your body. This is because high blood pressure increases the resistance your heart must pump against. Over time, all that extra work can wear out your heart and lead to heart failure. Heart muscle damage that is caused by high blood pressure is often called hypertensive cardiomyopathy.
- Heart valve problems. Heart valves control the direction of blood flow through your heart. When they’re damaged, they often don’t open and close properly. This leads to backflow of blood or limits the forward flow of blood. Congenital defects (defects present at birth) and infections such as rheumatic fever can cause heart valve problems that interfere with your heart’s ability to pump blood effectively. This is called valvular cardiomyopathy.
- Alcohol abuse. Chronic, excessive alcohol intake can severely weaken the muscle walls of the heart. This problem is called alcohol-related heart failure, or alcoholic cardiomyopathy.
- Unknown causes. Sometimes the cause for heart failure is unknown. If tests and examinations cannot find a specific cause for the weakening of your heart, your healthcare providers will say that you have idiopathic cardiomyopathy.