Mitral valve echoes in patients with mitral valve prolapse syndrome.

Echocardiology is an important tool in diagnosing patients with the mitral valve prolapse (MVP) syndrome. An unusual echocardiographic finding reported in this study was observed in 12 of 83 patients (14.5 per cent) with MVP syndrome. The finding consisted of a pattern of multiple, high-intensity parallel echoes behind the anterior mitral leaflet noted throughout diastole which in character were closely akin to those previously observed in left atrial myxoma or hemodynamically significant flail mitral valve leaflet. These latter diagnoses were excluded by other criteria. The prevalence of this finding in patients with MVP was significantly increased (P < .01 by Chi-square contingency testing) when contrasted with 44 patients without MVP. There was no identifying feature in the clinical history or physical examination which could be used to predict those in whom the diastolic echoes were observed. However, a significant increase in dysrhythmias as recorded by routine electrocardiogram or 24-hour Holter monitoring was noted. Angiographic information obtained in selected patients suggested that the posterior leaflet per se caused these diastolic echoes. Because of patulous transformation of the valve, elongation of the chordae, or loss of support of the papillary muscle from the posterior free wall, the posterior leaflet appeared drawn forward toward the anterior leaflet, perhaps from a venturi-like effect caused by the rapid ingress of blood during diastolic filling. This malpositioning of the posterior leaflet was not associated with significant mitral regurgitation and appears to represent but another facet in the spectrum of mitral valve prolapse.