EVALUATION OF LEFT VENTRICULAR PREEJECTION SYSTOLE IN NORMAL CHILDREN BY ECHOCARDIOGRAPHY

Abstract

The period of systole prior to left ventricular (LV) ejection (PES) can be assessed from echograms (E), by measuring the interval from the onset of the electrical Q wave to: coaptation of the mitral valve (Q-M) or opening of the aortic valve (Q-AO), and to the onset of systolic excursions of the ventricular septum (Q-S) or posterior left ventricular wall (Q-LVW). Thus we studied a group of clinically normal school children to establish standards for these different PES, and to examine the Interrelationships between these normal events. Strip chart E were obtained from a LV sector containing mitral echoes, and from a plane of the aortic root in which valve motion was well recorded, using a 2.25 MHz transducer. PES intervals were measured in milliseconds and mean and standard error of mean values were: Q-M 49.4±1.6, Q-AO 74.0±2.4, Q-S 78.2±2.2 and Q-LVW 109.0±2.4. The differences between Q-M and Q-AO (25.1) was highly significant (p=<0.001) and represents LV isovolumic contraction time. The shorter duration of Q-S than Q-LVW (31.0) with p=<0.001 reflects the conduction time along the left branch from S to LVW. Thus this study demonstrates that PES can be analyzed from a variety of reference points recorded by E. In addition E analysis of PES may be utilized to evaluate Isovolumic systole and conduction velocity along the left bundle branch. These results also indicate that the aortic valve opening is not dependent on the systolic Inward excursion of S and LVW.