What Is Heart Valve Disease?
There are four valves in the heart that keep blood from flowing back, maintaining the one-way flow out of the heart. The closure of each valve is by flaps (“cusps” or “leaflets”) which shut only to the point of closure, preventing them from swinging back open past the closure point.
Left Side of the Heart (Oxygenated Blood)
- Mitral Valve: A two-leaf valve (“bicuspid” or “semi-lunar”) situated between the left atrium and left ventricle (“atrioventricular”), keeps blood in the left ventricle from flowing back into its respective atrium with ventricular contraction.
- Aortic Valve: A three-leaf valve (“tricuspid”) situated between the left ventricle and the aortic flow, keeps blood in the aortic arch from flowing back into the left ventricle after its contraction.
Right Side of the Heart (Deoxygenated Blood)
- Tricuspid Valve: A three-leaf (“tricuspid”) valve situated between the right atrium and right ventricle (“atrioventricular”), keeps blood in the right ventricle from flowing back into its respective atrium with ventricular contraction.
- Pulmonic Valve: A three-leaf valve (“tricuspid”) situated between the right ventricle and the pulmonary artery to the lungs, keeps blood in the pulmonary artery from flowing back into the right ventricle after its contraction.
Thus, the left atrioventricular (mitral) valve and the aortic valve keep blood flowing one-way through the left side of the heart and onward to the aorta; the right atrioventricular (tricuspid) valve and the pulmonary valve keep blood flowing one-way through the right side of the heart and onward to the pulmonary trunk (artery).
- Stenosis: when a valve is scarred or calcified such that it is stiff, hampering the mobility of its leaflets from closing properly or from allowing a smooth flow across them.
- Insufficiency: when damage or weakness to the structural integrity of the leaflets is such that it cannot close completely, allowing backflow of blood, called “regurgitation.”
Whether the flow is compromised by stenosis or reversed in part from insufficiency, the efficiency of the heart as a pump is decreased, the severity of valvular disease varying consistently with the severity of the compromise.
- Mitral Stenosis: Primarily in the young, rheumatic fever the leading cause. Obstruction to flow is from calcification, a scarring phenomenon.
- Mitral Regurgitation: Common in the elderly, it is caused by leaflet weakness, ischemia or infarction, or left ventricular enlargement.
- Aortic Stenosis: In the elderly, primarily, due to calcification or degeneration of the aortic valve. Most commonly, it is caused by the calcifications that result in obstructed blood flow with or without accompanying regurgitation.
- Aortic Regurgitation: Age-associated risk-based, it is due to dilation of the ascending aorta from hypertension, calcification-related stenosis, or–acutely–due to aortic dissection or endocarditis.
- Tricuspid Stenosis: Uncommon (due mainly to rheumatic fever) that causes obstruction to flow from the right atrium with ramifications back through the venous side of the body, leading to liver enlargement and edema.
- Tricuspid Regurgitation: Fairly common valvular dysfunction, caused by abnormality of the leaflets themselves or rupture of the chordae tendineae, which are the “heart strings” that keep the valve from swinging back open in a retrograde fashion. It is also caused by right ventricular enlargement due to aging and atrial fibrillation.
- Pulmonary Stenosis: Usually a congenital condition, it occurs when two of the leaflets are locked/fused together or too thick, leading to obstruction of blood flow into the pulmonary artery.
- Pulmonic Regurgitation: Leaky pulmonary valve disease caused by pulmonary hypertension, infection, or congenital heart disease.
It is noteworthy that infective endocarditis from Staphylococcus or Streptococcal infections, or others, puts the heart valves at risk, tricuspid most commonly, followed by the mitral and aortic valves, with involvement of multiple valves being common.
Signs and Symptoms
The clinically evident results of valvular disease all are due to the deviation from the normal functioning of the heart, either by distorting heart chambers behind obstruction or regurgitation, or diminution of blood flow onward when obstructed.
- Heart murmur
- Atrial or ventricular enlargement
- Chest pain
- Dyspnea (shortness of breath)