Function of the healthy heart valves

Anatomy of the heart

The heart is a muscular hollow organ that pumps blood through the body with rhythmic contractions and in this way ensures the supply of all organs.

The heart lies in a connective tissue sac called the pericardium, which contains some fluid, allowing the organ to move smoothly. In the epicardial fat layer are the coronary vessels (coronaries) Under the epicardium is the actual muscular layer of the heart, the myocardium. The interior of the heart is lined by a thin skin called the endocardium.

The human heart has two atria (atrium) and two ventricles (ventricles). The atria and ventricles are separated by the cardiac septum.

The valves in the heart work as non-return valves, so that blood can only flow in one direction in a healthy heart. The arteries transport the blood from the heart to the organs, and from the organs to the heart.

The superior and inferior vena cava flow into the right atrium (RA). They carry the deoxygenated blood from the great circulation (systemic circulation) to the heart.

Between the right atrium and the right ventricle is the tricuspid valve, which prevents blood from flowing back into the atrium when the ventricles contract. From the right ventricle (RV), blood flows to the lungs. Backflow into the right ventricle is prevented by the pulmonary valve. The pulmonary arteries supply the deoxygenated blood to the (small) pulmonary circulation. Through the pulmonary veins, the blood that has been oxygenated in the lungs flows into the left atrium (LA). From here, it passes through the mitral valve to the left ventricle (LV). The outflow occurs via the aortic valve into the aorta.

Above the level of the aortic valve, the coronary vessels (coronaries) branch off from the aorta and supply the heart with blood and oxygen.

leaflet valves - atrioventricular valves

The two leaflet valves (atrioventricular valves, AV valves) are located at the atrioventricular junction. The mitral valve has two delicate leaflets and is located in the left heart. The tricuspid valve with three leaflets is located in the right heart.

Tendon threads are attached to the free edges of the leaflets, which originate from the papillary muscles (small protrusions of the inner wall of the ventricle). The tendon filaments prevent the free edges of the leaflet valves from recoiling into the atria during contraction of the ventricle (systole). Because the leaflets lie tightly against each other when the valve is completely closed in healthy individuals, they seal the opening to the atrium in this way.

Mitral valve

Tricuspid valve

Mitral valve

The mitral valve sits between the left atrium and the left ventricle. It prevents the backflow of blood from the left ventricle into the left atrium of the heart during (systole) where it is closed. During the relaxation and filling phase (diastole), the valve is open and allows the chamber to fill.

The mitral valve consists of two delicate, connective tissue leaflets. The leaflets of the mitral valve are attached to the papillary muscles facing the ventricle by tendon threads.

The valve leaflets passively lay flush against each other when the pressure in the left ventricle increases. The papillary muscles prevent the mitral valve from flipping over into the left atrium by pulling on the chordae synchronously with the contraction of the ventricle.

The narrowing of the opening located between the valve leaflets causes what is most common in rheumatic valve disease. The leaky valve leads to loss of closing ability and causes mitral valve regurgitation. Systolic protrusion of the mitral valve into the left atrium is called mitral valve prolapse, which is often asymptomatic and does not require treatment.

Diseases and therapy of the mitral valve:

• Mitral valve stenosis
• Mitral valve regurgitation

Tricuspid valve

The tricuspid valve sits between the right atrium and the right ventricle. As a valve, the tricuspid valve prevents blood from flowing back from the right ventricle into the right atrium during the blood outflow phase. (Systole). During the relaxation and filling phase (diastole), the valve is open and allows the chamber to fill.

The tricuspid valve consists of three delicate, connective tissue leaflets. The leaflets of the tricuspid valve are attached to the papillary muscles facing the ventricle by tendon threads.

The valve leaflets passively lay flush against each other when the pressure in the right ventricle increases. The papillary muscles prevent the tricuspid valve from flipping over into the right atrium by pulling on the chordae synchronously with the contraction of the ventricle.

The tricuspid valve is much less frequently affected by valve disease. A diseased tricuspid valve can be leaky (insufficient) or narrowed (stenosed).

The leaky valve leads to loss of closing ability and causes tricuspid regurgitation. Narrowing of the opening between the valve leaflets causes tricuspid valve stenosis.

Diseases and therapy of the tricuspid valve:

• Tricuspid regurgitation

Pocket flaps - Semilunar flaps

The two semilunar valves are the aortic valve and the pulmonary valve. They are located at the beginning of the two arteries leading from the ventricles.

The two semilunar valves consist of three crescent-shaped pockets each, which hang from the inner wall of the relevant artery - aorta with aortic valve and pulmonary valve with pulmonary artery - and whose free edge is thickened in the middle. These thickened of the edges of the pocket valves meet when the valves close, thereby sealing the opening to the ventricle.

Aortic valve

Pulmonary valve

Aortic valve

The aortic valve is located between the left ventricle and the aorta. As a valve to the aorta, the aortic valve prevents the backflow of blood from the aorta in the left ventricle during the blood relaxation and filling phase (diastole).

The aortic valve consists of three valve pockets. The pockets are indented towards the heart and can fill with blood. At the free end of each valve pocket is a nodule, framed by a crescent-shaped valve leaflet. The aortic valve is slightly larger and thicker than the related pulmonary valve because of the greater stress placed on it.

During cardiac action, the left ventricle pumps blood into the aorta by contraction during the blood outflow phase (systole). As long as the pressure in the left ventricle exceeds the pressure in the aorta, no backflow of blood into the left ventricle is possible.

The blood now in the ascending part of the aorta would flow into the left ventricle without the closure of the aortic valve. When the valve is functioning correctly, the valve pockets fill at the beginning of the blood relaxation and filling phase (diastole) and cause closure. The backflow of blood is thus effectively prevented.

The diseased aortic valve may be narrowed (stenosed) or leaking (insufficient). The narrowing of the aortic valve causes aortic valve stenosis and increases the pressure load on the heart. The leaky aortic valve causes aortic regurgitation and increases the volume load on the heart.

A common heart valve defect is also the bicuspid aortic valve, when the aortic valve has only two valve pockets instead of three. This valve malformation can lead to stenosis between the ages of fifty and sixty.

Diseases and therapy of the aortic valve:

• Aortic valve stenosis
• Aortic valve regurgitation

Pulmonary valve

The pulmonary valve is located between the right ventricle and the pulmonary artery. The healthy pulmonary artery valve prevents the backflow of blood from the pulmonary artery in the right ventricle during the blood relaxation and filling phase (diastole).

Like the aortic valve, the pulmonary valve is composed of three crescent-shaped pockets (semilunar valve). The pulmonary valve is much less frequently affected by valve diseases. It can be either narrowed (stenosed) or leaky (insufficient).

A narrowing of the pulmonary valve is called pulmonary stenosis. It increases the pressure load on the ventricle. Dilatation or loosening of the pulmonary valve is called pulmonary regurgitation and increases the volume load on the right ventricle. Both changes lead to a right ventricular strain.

Pulmonary valve