Causes of Heart Valve Diseases
Heart conditions and other disorders, age-related changes, rheumatic fever, or infections can cause acquired heart valve disease. These factors change the shape or flexibility of once-normal heart valves. The cause of congenital heart valve disease isn’t known. It occurs before birth as the heart is forming. Congenital heart valve disease can occur alone or with other types of congenital heart defects.

1. Rheumatic Fever
Untreated strep throat or other infections with strep bacteria that progress to rheumatic fever can cause heart valve disease. When the body tries to fight the strep infection, one or more heart valves may be damaged or scarred in the process. The aortic and mitral valves most often are affected. Symptoms of heart valve damage often don’t appear until many years after recovery from rheumatic fever.

Today, most people who have strep infections are treated with antibiotics before rheumatic fever occurs. If you have strep throat, take all of the antibiotics your doctor prescribes, even if you feel better before the medicine is gone. Heart valve disease caused by rheumatic fever mainly affects older adults who had strep infections before antibiotics were available. It also affects people from developing countries, where rheumatic fever is more common.

2. Infections
Common germs that enter the bloodstream and get carried to the heart can sometimes infect the inner surface of the heart, including the heart valves. This rare but serious infection is called infective endocarditis. The germs can enter the bloodstream through needles, syringes, or other medical devices and through breaks in the skin or gums. Often, the body’s defenses fight off the germs and no infection occurs. Sometimes these defenses fail, which leads to infective endocarditis.

Infective endocarditis can develop in people who already have abnormal blood flow through a heart valve as the result of congenital or acquired heart valve disease. The abnormal blood flow causes blood clots to form on the surface of the valve. The blood clots make it easier for germs to attach to and infect the valve.

3. Heart Conditions and Other Disorders
Certain conditions can stretch and distort the heart valves. These conditions include:
-- Advanced high blood pressure and heart failure, this can enlarge the heart or the main arteries.
-- Atherosclerosis in the aorta. Atherosclerosis is a condition in which a waxy substance called plaque builds up inside the arteries. The aorta is the main artery that carries oxygen-rich blood to the body.
-- Damage and scar tissue due to a heart attack or injury to the heart.