Valvular Heart Diseases

Anatomy

Our heart is a muscular pump approximately the size of a clenched fist in an adult. Its main function is to pump blood throughout the body. The heart has four chambers — two upper chambers called atria, which receive blood from the veins, and two lower chambers called ventricles, which pump blood through the arteries to the rest of the body.

To ensure that blood flows regularly and in an orderly manner to different organs, valves are located at the inlets and outlets of the ventricles. Physiologically, the heart is divided into the right heart and the left heart.

The right heart receives deoxygenated (impure) blood returning from all parts of the body into the right atrium. The blood then passes through the tricuspid valve (located between the right atrium and right ventricle) into the right ventricle. When the right ventricle contracts, blood flows through the pulmonary valve (between the right ventricle and the pulmonary artery) and enters the lungs for oxygen exchange, becoming oxygenated (pure) blood.

The oxygenated blood then returns through the pulmonary veins into the left atrium, passes through the mitral valve (between the left atrium and left ventricle), and enters the left ventricle. When the left ventricle contracts, blood is pumped to the entire body. This sequence continues regularly and uninterrupted, about 60–80 times per minute throughout life.

Mechanism of Valvular Heart Diseases

Under normal conditions, each of the four heart valves acts as a one-way valve, allowing blood to pass in only one direction. The main components of these valves are leaflets — thin yet strong tissues that open like doors in one direction. At the beginning of heart muscle contraction, the leaflets open to let blood flow freely through the valve; at the end of contraction, they close tightly to prevent blood from flowing backward.

Some diseases cause the valve leaflets to fail to close completely after blood passes through, allowing a portion of blood to leak backward. This condition is called valvular regurgitation (insufficiency). Conversely, some diseases cause the valve opening to narrow or fail to open fully, creating resistance to blood flow and reducing the volume passing through. This condition is called valvular stenosis (narrowing).

To grasp the perfection of creation, note that each of the four heart valves opens and closes over 100,000 times per day without blocking blood flow or allowing backflow.

Types of Valvular Heart Diseases

There are two main categories of valvular diseases — stenosis and regurgitation — each caused by different underlying conditions:

A) Rheumatic Heart Disease

The most common cause of valvular disease in our country and many developing countries is rheumatic heart disease. This chronic condition thickens, stiffens, and deforms the valve leaflets, leading to mitral stenosis, aortic stenosis, tricuspid stenosis, and rarely, pulmonary stenosis.

In such cases, stenosis is often accompanied by varying degrees of regurgitation. To better understand, imagine a wooden door that has warped and decayed due to exposure to weather; it neither opens nor closes properly, allowing outside air to continuously leak in. The same happens with rheumatic valves.

B) Degenerative (Dystrophic) Diseases

In these conditions, the valve leaflets become thin, weak, and floppy, causing the valve to enlarge. These diseases usually manifest as valvular regurgitation, but in some elderly patients, they can also appear as aortic stenosis.

C) Infectious Diseases

Sometimes, during a bacterial infection, the heart valves become directly infected — a condition called endocarditis. This leads to valve destruction and acute or chronic valve insufficiency.

D) Congenital Diseases

All heart valves may be congenitally stenotic or insufficient. Valvular involvement can also occur as part of a complex congenital heart defect.

E) Trauma

Occasionally, direct or indirect trauma to the chest can cause tears in the valve structures, leading to valvular insufficiency.

Symptoms of Valvular Heart Diseases

Although symptoms vary depending on which valve is affected, the most common and important symptom is shortness of breath during physical activity. If you feel breathless while climbing stairs, running, walking uphill, or exercising — especially if this is new or occurs with lighter activity than before — you should consult your doctor.

Other symptoms may include fatigue, weakness, chest pain, leg swelling, shortness of breath while lying flat, or palpitations.

Remember that valvular heart disease is only one of several possible causes of shortness of breath, so there is no need for unnecessary anxiety.

Prevention of Valvular Heart Diseases

Although complete prevention may seem difficult, understanding the causes reveals that many cases can be prevented indirectly.

For example, while congenital defects cannot be controlled by the patient, parents can help reduce the risk by:

  • Avoiding consanguineous (family) marriages,

  • Seeking genetic counseling before marriage,

  • Avoiding alcohol and tobacco use during pregnancy, and

  • Avoiding self-medication during this period.

These actions can significantly reduce the likelihood of congenital heart defects, including those affecting the valves.