Etiology of valvular heart disease.

The incidence of congenital valvular heart disease has not significantly altered in recent decades. Major factors contributing to altered profiles of acquired valvular heart disease in the past few decades include an increased elderly segment of the population and increasing recognition of nonrheumatic forms of valvular heart disease. Mitral valve prolapse, and similar involvement of other valves, together with senile calcific aortic stenosis have emerged as the most common forms of valvular heart disease in developed countries. Body leanness and hypertension are additional etiological factors for senile calcific aortic stenosis. Severe calcification of a congenital bicuspid aortic valve continues to be an important cause of aortic stenosis in the elderly. Idiopathic degeneration of the aortic and mitral valves, apparently a different condition than mitral valve prolapse, has also become recognized. Despite a recent increase in the incidence of acute rheumatic fever in North America, rheumatic heart disease remains an infrequent cause of valvular heart disease in developed nations. Its incidence has diminished in the Middle East, but it is still frequent in underdeveloped countries. Intravenous drug abuse is increasing in importance as a cause of valvular heart disease in urban centers in the United States. Syphilitic heart disease is very rare.