Two thousand and sixteen young students (18-22 yrs) were prospectively examined for the presence of mitral valve prolapse (MVP) as manifested by two-dimensional echocardiography. Abnormalities of mitral valve closure in systole (slip, displaced coaptation and dislocation of either or both mitral leaflets) were found in 24.4% of 1767 male students and in 31.9% of 249 female students. Twenty five students (1.2%) showed marked superior motion of anterior mitral leaflet above the level of the mitral ring in systole. Among the 25 students with marked MVP, 20 underwent further examination about the clinical features. One had pectus excavatum. The mean ratio of anteroposterior to lateral chest diameters was lower in the MVP group (61±7%) than in normal students (70±5%). During postural test, abnormal response of either heart rate or blood pressure to standing, vagotonic response such as orthostatic hypotension or hyperadrenergic response such as marked tachycardia was demonstrated in 5 students. An increase in plasma norepinephrine concentration from supine to standing position was greater in the MVP group than in normal control group. Thus, the presence of narrow anteroposterior chest diameter and dysautonomia was noted in the MVP group. These may be partly related to the cause of MVP as suggested by previous investigators. As other clinical features, Holter ECG monitoring demonstrated supra ventricular tachycardia in 3 students including 1 with a complaint of syncope. Doppler echocardiography demonstrated a small degree of mitral regurgitation in 4 students. However, all the MVP students revealed no sign of either myocardial ischemia or heart failure at rest and during submaximal ergometer exercise test. These subjects with arrhythmia or mitral regurgitation should be needed long-term follow-up since the prognosis has not been well elucidated. From these results, we recognized the importance of the screening test for mitral valve prolapse by two-dimensional echo cardiography in the young population.

DESCENTE SPORTS SCIENCE Vol.9/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE