THE RATIO OF SYSTOLIC TIME INTERVALS OF LEFT VENTRICLE IN NORMAL CHILDREN-ECHOCARDIOGRAPHIC STUDY

Current techniques utilize data derived from the aortic valve (AV) to determine the ratio between the pre-ejection (PEP) and ejection period (EP) of left ventricle (LV) in children. Mitral valve (MV), septum (S) and posterior LV wall (LVW) motion, can also be obtained and may be of value in the measurement of systolic time intervals (STI) by echograms (E). Thus, we studied a group of 40 normal school children by E to establish normal standards for PEP/EP for 4 reference points at MV, AV, S and LVW. PEP was measured from the onset of Q wave of the EKG to: 1-coaptation of MV (MPEP), 2-to the opening point of AV (APEP), 3-to the onset of systolic posterior excursion of S (SPEP) and 4-to the onset of anterior systolic motion of LVW (LVWPEP). EP was measured for: 1-total coaptation time of MV (MEP), 2-seperated interval of AV (AEP), 3-from the onset to the point of maximum systolic posterior excursion of S (SEP) and 4-similar to S for LVW anterior motion (LVWEP). PEP/EP ratios were computed for several cardiac cycles and averaged. Results of mean and standard error of mean were: MPEP/MEP 0.154±0.005, APEP/AEP 0.275±0.012, SPEP/SEP 0.304±0.009 and LVWPEP/LVWEP 0.390±0.011. Our study establishes normal standards for ratios of STI of 4 different reference points of LV in children which do not appear to be interchangable as they reflect different intracardiac events. (Sponsor: Eli Gold)