Real time observation of the echo source of systolic hump in hypertrophic obstructive cardiomyopathy with high speed ultrasono-cardiotomography.

The present study was undertaken to discuss the echo source of systolic hump in hypertrophic obstructive cardiomyopathy (HOCM) from a viewpoint of B-mode echocardiography. Cross-sectional images were obtained from 4 patients with HOCM using a Sonolayergraph of Toshiba, SSL-51H. This equipment is characterized by its high speed mechanical sector scanning and wider angle. Recordings were made with ordinary 35 mm camera or Polaroid in conjunction with 8 mm cinecamera. Our data showed that systolic hump in this lesion was not caused by anterior systolic movement of anterior mitral leaflet, but was emanated from the chordae tendineae attached to the anterior or posterior mitral leaflet. In systole, the anterior mitral leaflet moved backward for closure, while the chordae tendineae approached the bulged interventricular septum resulting in the formation of systolic hump.