While there are many causes of valvular heart disease (including rheumatic fever, congenital heart disease, cardiac dilation, and age-related calcification of the valves), whatever the cause, heart valve problems are generally manifested in one of two ways. Either the valve openings become too narrow and blood has a difficult time crossing the valves (i.e., stenosis), or the valves become incompetent, allowing blood to leak across the valves when they are supposed to be closed (i.e., regurgitation).
Valvular stenosis causes damming up of the blood behind the valve. This damming up of blood leads to increased pressure in the cardiac chambers behind the valve.
Valvular regurgitation allows blood to wash backwards across the valve when the valve should be closed. This extra volume of blood produced by this backwash causes dilation of the cardiac chambers receiving the extra blood.
Both increased pressures and increased blood volume in any of the cardiac chambers can eventually produce permanent weakening of the cardiac muscle, and can ultimately lead to heart failure. Either stenosis or regurgitation in a cardiac valve causes turbulence of blood flow, and that turbulence is detected as a heart murmur when the doctor listens to the heart with a stethoscope. Generally, heart valve problems can be readily diagnosed by performing an echocardiogram.
The tricuspid valve
The tricuspid valve separates the right atrium from the right ventricle. When the tricuspid valve develops stenosis, increased pressure in the right atrium leads to high pressure in the veins throughout the body, causing edema (swelling) of the liver, abdomen and legs. When tricuspid regurgitation occurs, both the right atrium and right ventricle tend to dilate, reducing the efficiency of both these cardiac chambers.
The pulmonic valve
The pulmonic valve separates the right ventricle from the pulmonary artery. With pulmonic stenosis there is increased pressure in the right ventricle. With pulmonic regurgitation there is volume overload of the right ventricle. Either way, the right ventricle can ultimately fail.
The mitral valve
The mitral valve separates the left atrium from the left ventricle. Mitral stenosis causes damming up of blood in the left atrium, and ultimately in the lungs. Mitral regurgitation causes dilation of both the left atrium and left ventricle, and can lead to failure of both cardiac chambers. Mitral valve prolapse (MVP) is a common condition that results in one of the leaflets of the mitral valve flopping backwards into the atrium during the contraction of the left ventricle. MVP often involves at least mild regurgitation. Click here for a discussion of MVP
The aortic valve
The aortic valve separates the left ventricle from the aorta. Aortic stenosis causes increased pressure in the left ventricle. (Click here for a complete discussion of aortic stenosis
.) Aortic regurgitation causes dilation of the left ventricle. Both of these aortic valve problems can lead to heart failure.