Heart disease is the leading cause of death in the United States. Simply defined, heart disease is any process that caused the heart to work harder, or pump less efficiently. While heart disease can lead to a heart attack, heart disease should not be confused with a heart attack (myocardial infarction). Heart disease is caused by many factors ranging from viral infection to being born with heart defects. The two main causes of heart disease are ischemic heart disease and hypertensive heart disease. Other less common causes of heart disease have to do with bacterial infections, inflammation of the heart, swelling of the tissues around the heart and death of the cardiac muscle in the heart.
Ischemic Heart Disease
This is the most common form of cardiac disease. It is essentially an imbalance between oxygen supply and demand for the heart. It is vital for the heart to get the oxygen supply it needs first, so that it may continue to pump the blood and oxygen to the rest of the body. Ischemic heart disease is mainly caused by atherosclerosis (build up of fat and thickening of the artery wall). It can take up to 70 percent occlusion before any symptoms present. The plaque (fat) build up makes it harder for the blood to pass through (like a traffic jam when one lane is closed). Since atherosclerosis can be well progressed before symptoms are felt, angina pectoris (chest pain) is usually the first sign. This pain comes from the heart sending out a signal that it does not have enough blood, much like your other muscles do when you work them hard. Pain is mostly noticed with increased activity. If no period of chest pain is felt, then other signs can be similar to that of atherosclerosis symptoms, like high cholesterol and peripheral artery occlusive disease (PAOD). This will eventually lead to other problems like heart attack or stroke.
Hypertensive Heart Disease
High blood pressure will eventually cause the heart to work harder to pump the blood throughout the body and ultimately cause the left ventricle of the heart to grow very large. This ventricle is the main part of the heart that pumps the blood into the body, so to overcome the higher pressure in the body, it has to pump harder. Since it is a muscle, the harder it works, the larger it becomes. The high blood pressure can be caused by a variety of sources from genetic factors to smoking. Signs with this disease include high blood pressure and enlarged left ventricle seen by imaging. Other signs will include signs of renal failure, arteriosclerosis (hardening of the blood vessels), stroke and heart attack. Occasionally, the right ventricle can enlarge and cause problems with breathing, as the blood does not get pumped as effectively through the lungs.
Congenital Heart Disease
This is the most common cause in children under 4 years old. Most of these deformities are caused by unknown circumstances, while a small percentage are due to genetic abnormalities and diseases. An even smaller percentage is caused by environmental factors while in utero. The abnormalities with the heart will vary, but ultimately, the heart becomes an ineffective pump. Depending on what is wrong will depend on what is done from monitoring only to valve surgery or heart replacement.
References
- "Basic Sciences to Clinical Competency 4th edition;" Nikita Vizniak, et al; 1999
