Mitral Leaflet Billowing and Prolapse: Its Prevalence Around the World

Abstract

Primary mitral leaflet billowing, or so-called mitral valve prolapse, has become the most common valve anomaly in the United States and is also frequently found throughout the world. Its prevalence varies from less than 1% to 38%, differing not only between countries but also within the same country. The prevalence de pends on whether the study is clinical or echocardiographic, based on au topsy or surgical material, or of hos pital or non-care-seeking population. Other explanations for the varying prevalence are the age, sex and weight differences of the study popu lation, imprecise terminology, the care with which auscultation and/or echocardiography are carried out and interpreted, and some selection biases. Although prevalent throughout the world, the condition is generally benign and can often be regarded as a normal variant. Among the compli cations of mitral valve prolapse, pro gressive mitral regurgitation and in fective endocarditis are particularly noteworthy. Primary mitral valve prolapse is currently a leading cause of mitral regurgitation and also of in fective endocarditis.