- High blood pressure
- Some over-the-counter medications, prescription medications, dietary supplements and herbal remedies
- Valvular heart disease
In a healthy person with a normal, healthy heart, it’s unlikely for a deadly arrhythmia to develop without some outside trigger, such as an electrical shock or the use of illegal drugs. However, in a heart that’s diseased or deformed, the heart’s electrical signals may not properly start or travel through the heart, making arrhythmias more likely to develop.
Causes of congenital heart defects
Congenital heart defects usually develop while a baby is in the womb. Heart defects can develop as the heart develops, about a month after conception, changing the flow of blood in the heart. Some medical conditions, medications and genes may play a role in causing heart defects.
Heart defects can also develop in adults. As you age, your heart’s structure can change, causing a heart defect.
Causes of cardiomyopathy
The cause of cardiomyopathy, a thickening or enlarging of the heart muscle, may depend on the type:
- Dilated cardiomyopathy. The cause of this most common type of cardiomyopathy often is unknown. The condition usually causes the left ventricle to widen. Dilated cardiomyopathy may be caused by reduced blood flow to the heart (ischemic heart disease) resulting from damage after a heart attack, infections, toxins and certain drugs, including those used to treat cancer. It may also be inherited from a parent.
- Hypertrophic cardiomyopathy. This type usually is passed down through families (inherited). It can also develop over time because of high blood pressure or aging.
- Restrictive cardiomyopathy. This least common type of cardiomyopathy, which causes the heart muscle to become rigid and less elastic, can occur for no known reason. Or it may be caused by diseases, such as connective tissue disorders or the buildup of abnormal proteins (amyloidosis).
Causes of heart infection
A heart infection, such as endocarditis, is caused when germs reach your heart muscle. The most common causes of heart infection include:
Causes of valvular heart disease
Many things can cause diseases of your heart valves. You may be born with valvular disease, or the valves may be damaged by conditions such as:
- Rheumatic fever
- Infections (infectious endocarditis)
- Connective tissue disorders
Risk factors for developing heart disease include:
- Age. Growing older increases your risk of damaged and narrowed arteries and a weakened or thickened heart muscle.
- Sex. Men are generally at greater risk of heart disease. The risk for women increases after menopause.
- Family history. A family history of heart disease increases your risk of coronary artery disease, especially if a parent developed it at an early age (before age 55 for a male relative, such as your brother or father, and 65 for a female relative, such as your mother or sister).
- Smoking. Nicotine tightens your blood vessels, and carbon monoxide can damage their inner lining, making them more susceptible to atherosclerosis. Heart attacks are more common in smokers than in nonsmokers.
- Poor diet. A diet that’s high in fat, salt, sugar and cholesterol can contribute to the development of heart disease.
- High blood pressure. Uncontrolled high blood pressure can result in hardening and thickening of your arteries, narrowing the vessels through which blood flows.
- High blood cholesterol levels. High levels of cholesterol in your blood can increase the risk of plaque formation and atherosclerosis.
- Diabetes. Diabetes increases your risk of heart disease. Both conditions share similar risk factors, such as obesity and high blood pressure.
- Obesity. Excess weight typically worsens other heart disease risk factors.
- Physical inactivity. Lack of exercise also is associated with many forms of heart disease and some of its other risk factors as well.
- Stress. Unrelieved stress may damage your arteries and worsen other risk factors for heart disease.
- Poor dental health. It’s important to brush and floss your teeth and gums often, and have regular dental checkups. If your teeth and gums aren’t healthy, germs can enter your bloodstream and travel to your heart, causing endocarditis.