The Effect of Transducer Placement on the Echocardiographic Pattern of Mitral Valve Prolapse

Abstract

Specific patterns of mitral valve prolapse have been identified with echocardiography. The variability of presentation of these patterns within a single patient has been noted in our laboratory. In an attempt to clarify this variability, echocardiographic studies were carried out in 100 presumably normal females aged 18 to 35. Echocardiograms of the mitral valve were performed from the second, third, fourth, and fifth intercostal spaces and orientation of the transducer in each of these interspaces was noted. Subjects with no evidence of mitral valve prolapse show a flat or posterior systolic segment from the second intercostal space with caudal transducer direction. Perpendicular placement of the transducer in the third intercostal space shows a gradual anterior migration of the mitral valve during systole. Cephalad direction of the transducer from the fourth intercostal space or below shows a markedly anterior systolic segment of the mitral valve. This pattern is apparently related to descent of the mitral annulus towards the apex during ventricular contraction and the component of this motion registered along the path of the sound beam. The posterior motion of the mitral valve seen in mitral valve prolapse can be reliably recorded only when the transducer is perpendicular to the chest wall as caudal direction of the transducer gives false positive records and cephalad direction of the transducer gives false negative records.