The human heart consists of four chambers: the two upper chambers known as the right and left atria, and the two lower chambers known as the left and right ventricle. Blood flows from one chamber to another through heart valves, which open and close allowing blood to flow in only one direction. Each of the four heart valves contain a set of flaps called cusps supported by a ring of fibrous tissue called the annulus, which helps the valve maintain its shape. Damage to one of the heart valves can interfere with its ability to open and close completely, therefore, affecting the flow of blood.
Rheumatic Fever
Rheumatic fever occurs when a strep throat infection caused group A streptococcal bacteria remains untreated. The body produces antibodies to fight the infection that can attack connective tissues, including those in the joints and the heart. The resulting inflammation damages heart tissue, usually the heart valves, leading to scarring. The scarred heart valves, a condition known as Rheumatic heart disease, cannot open and close properly causing them to leak. Although the incidence of Rheumatic fever remains low in the United States, it continues to be a leading cause of cardiovascular death during the first five years of life in developing nations, according to the American Heart Association.
Endocarditis
Endocarditis, infection of the lining of the heart and the heart valves, occurs when bacteria enter the bloodstream and become lodged on the heart valves. Normal heart valves can often fight off an infection, leaving previously damaged heart valves, including those damaged from rheumatic fever, at a higher risk for developing endocarditis. Endocarditis can cause a heart valve to perforate, or tear, causing it to leak, as described by the Merck Manual.
Heart Attack
A heart attack occurs when the heart becomes oxygen-deprived due to a decrease in blood flow to the heart, causing damage to the heart muscle. This damage can occur anywhere in the heart including the heart valves. A heart attack can stretch or tear the papillary muscles, the muscles inside the ventricles that keep the cusps of the valves stable against the backward flow of blood. Stretching these muscles causes the valves to leak. A heart attack can also cause the annulus to widen or stretch, thereby, allowing blood to leak through the valve, as described by the Cleveland Clinic.
High Blood Pressure
Blood pressure describes the force of the blood against the blood vessel walls. A normal blood pressure reading consists of a systolic of 120 mm Hg or less, and a diastolic of 80 mm Hg or less, according to the Cleveland Clinic. Doctors classify blood pressure as high, a condition known as hypertension, when it reads 140 mm Hg or higher over 90 mm Hg or higher.
Continuous increased pressure against the blood vessel walls causes damage to the blood vessels that over time, can lead to serious damage to other organs including the heart. High blood pressure causes the heart to work harder in order to pump blood. This strain on the heart weakens it, resulting in damage to tissues, including the heart valves, which can lead to heart valve leakage.
