[M-mode echocardiographic standardization of interventricular septal motion and its clinical significance].

Systolic and diastolic motions of the interventricular septum (IVS), especially of its lower portion at the level of the chordae tendineae, were evaluated by M-mode echocardiography in normal subjects and in patients with various cardiac disorders. The following conclusions were derived from this study. In normal subjects, downward motion of the IVS exhibited three patterns; namely, P1, between the onset of electrical depolarization and the onset of the second heart sound; P2, between the onset of the second heart sound and the E point of the anterior mitral leaflet; and P3, between the E point of the anterior mitral leaflet and the end of the left ventricular rapid filling phase, during each cardiac cycle. The systolic IVS pattern (P1) of atrial septal defect was classified as follows: Normal type: nearly normal posterior motion during ventricular systole, Flat type: flat motion during ventricular systole, Paradoxical (early systolic) type: anterior motion during the first half of ventricular systole, followed by normal posterior motion, Paradoxical (pansystolic) type: anterior motion during ventricular systole. In atrial septal defect, the right ventricular dimension was markedly increased in the flat and paradoxical (pansystolic) types compared with those of the normal and paradoxical (early systolic) types. Marked downward IVS motion (P2) was observed in cor pulmonale with paradoxical pulse, pulmonary hypertension, Ebstein's anomaly, pulmonic insufficiency, atrial septal defect, funnel chest, tricuspid insufficiency and constrictive pericarditis. In cor pulmonale with paradoxical pulse, the deep downward motion (P2) was observed more distinctly during inspiration compared to expiration, and right ventricular inflow velocity pattern was characterized by an apparent increase in peak flow in velocity of the diastolic rapid filling wave during inspiration. Two interesting findings were a deep "y" trough of the jugular pulse tracing and prominent P2 in funnel chest. Therefore, it was likely that exaggerated P2 seemed to be direct evidence of a marked increase in right ventricular rapid filling in the presence of normal or decreased left ventricular rapid filling. The augmented septal dip of P3 was observed in cases with the third heart sound as in normal subjects, and those with mitral insufficiency, and ventricular septal defect, constrictive pericarditis and mitral stenosis. We theorized that exaggerated P3 results from the "sucking action" secondary to increased left ventricular rapid filling velocity in cases with the third heart sound or constrictive pericarditis.(ABSTRACT TRUNCATED AT 400 WORDS)