The following objectives will be described for each of the major valvular heart disorders, including: (1) aortic stenosis and aortic regurgitation; (2) mitral stenosis, mitral regurgitation, and mitral valve prolapse; (3) tricuspid stenosis and tricuspid regurgitation; and (4) pulmonary stenosis and pulmonary regurgitation. By the end of this chapter the student will be able to:
Describe the etiology, pathology, and natural history of valvular heart disease.
Describe the clinical symptoms and signs of valvular heart disease.
Explain the clinical examination findings of particular valvular problems.
Determine the role of echocardiograms in valvular heart disease, both in diagnosis and prognosis.
Discuss the long-term systemic consequences of valvular heart disease.
Describe the management and identify the indications of surgical intervention for particular valvular heart diseases.
Heart valves can be affected in 3 ways: regurgitation, stenosis, and atresia. Regurgitation, or backflow, occurs when a valve does not completely close. As a consequence, the blood leaks backward instead of flowing forward through the heart or into an artery. Stenosis occurs if the flaps of a valve thicken, stiffen, or fuse together. This prevents the heart valve from opening fully, and as a result, not enough blood flows through the valve. Some valves can have both stenosis and regurgitation. Atresia occurs if a heart valve has no opening for the blood to pass through.
Valvular heart disease can be caused by congenital or acquired etiology. Congenital heart valve disease presents as a discrete condition or as part of a complex syndrome. Congenital heart valve disease often involves the aortic or pulmonary valves that do not develop properly. Acquired heart valve disease usually affects the aortic or mitral valves. Although the valves are normal at first, problems gradually develop. Valve stenosis or regurgitation is caused by either congenital or acquired heart valve disease. Some valvular diseases are particular related to older age groups and an increase in prevalence has been observed recently as a result of an increase in aging populations, especially in the Western countries.
Aortic stenosis (AS) indicates a blood flow obstruction across the aortic valve, between the left ventricle and the aorta. The developed resistance in the blood flow, as a consequence, induces a pressure overload on the left ventricle, which if untreated can invariably lead to left heart dysfunction and failure. Meanwhile, aortic sclerosis is an entity that needs to be clearly differentiated from AS as it does not usually lead to the development of a significant pressure gradient across the valve, although it can cause turbulence and a murmur.
Etiology and Epidemiology
AS has a number of causative factors, the most important of which are mentioned here.
Senile Calcific or Degenerative Aortic Stenosis
This is the most common cause of AS ...