Obstructive Defects and Valvular Insufficiency
The term “obstructive heart defects” refers to an abnormality in the large vessels around the heart or in the heart valves that prevents blood from flowing freely. An obstructive heart defect creates high pressures in the heart and makes the heart work harder to pump the blood. The patient may be asymptomatic, but over time, a narrowed (stenotic) heart valve may become more thickened and result in increasing obstruction.
The term valvular insufficiency refers to an abnormality in the heart valves that results in “leaky” valves. Heart valves can be both obstructive and insufficient at the same time. If the heart valve leaflets are narrowed (stenotic) they can curl and blood can leak or flow back through the opening in the valve. The heart must work harder due to the increased volume of blood that must be pumped.
If the obstructive defect and/or valvular insufficiency are severe the child or adult may experience chest pain and dizziness, be fatigued, have a bluish color to the skin (cyanosis) and symptoms of heart failure. Medication, open heart surgery and/or a balloon valvuloplasty can restore normal blood flow in the heart.
Types of Obstructive Defects and Valvular Insufficiency:
- Aortic valve stenosis/ insufficiency – The aortic valve is positioned between the aorta and the left ventricle of the heart. At birth the aortic valve may have two leaflets rather than three resulting in impaired oxygen-rich blood flow to the body. This defect makes the left side of the heart work harder, and ultimately the right side of the heart must work harder to manage the back-up of blood in the heart.
- Mitral valve defects – The mitral valve is between the heart's left atrium (upper, holding chamber) and left ventricle (lower, pumping chamber). The mitral valve has two flaps, or cusps. Mitral valve prolapse (MVP) occurs when one or both valve flaps are enlarged, and some of their supporting "strings" may be too long. When the heart pumps (contracts), the mitral valve flaps don't close smoothly or evenly. Instead, part of one or both flaps collapses backward into the left atrium. This sometimes allows a small amount of blood leak backward through the valve. This may cause a heart murmur.
- Pulmonary valve stenosis/insufficiency – The pulmonary valve is positioned between the pulmonary artery and right ventricle of the heart. The three pulmonary valve leaflets are malformed with this defect, which can result in a narrowed (stenotic) and leaky valve. This defect makes the right side of the heart work harder to pump oxygen-depleted blood to the lungs.
- Tricuspid valve defects - In this condition, no blood can flow from the right atrium to the right ventricle because there is no tricuspid valve. As a result, the right ventricle is small and not fully developed. Surgical shunting is often needed to increase blood flow to the lungs. Patients with tricuspid atresia, before and after treatment, are at risk of developing endocarditis – an infection in the valves.
- Coarctation of the aorta – The aorta is the large artery that carries oxygen rich blood away from the heart to the body. Smaller arteries that carry blood to the head and arms, and the abdomen and legs branch off from the aorta. The term coarctation of the aorta refers to a narrowing of the aorta between the branches leading to the head and arms, and the branches leading to the abdomen and legs. This results in increased blood pressure to the head and arms and increases the work that your heart must do to push the blood to the abdomen and legs. This defect is often seen in conjunction with an aortic valve defect.
For additional information and illustrations of the above defects follow the American Heart Association links at http://americanheart.org; click on “diseases and conditions”, “adults with congenital heart disease”, congenital heart defects, and select the specific defect.