Evaluation and comparison of the axis of the interventricular septum by two-dimensional echocardiography among the patients with congenital heart disease (ASD, VSD, PDA, PS, TOF) and the normal subjects.

ABSTRACT

A two-dimensional echocardiographic method was applied to determine the axis of interventricular septum (IVS) in the horizontal plane. This study comprised 19 subjects with ASD, 15 subjects with VSD(I), 20 subjects with VSD(II), 13 subjects with PDA, 16 subjects with PS, 15 subjects with TOF and 99 normal children. Parasternal left ventricular short axis view was taken, and the IVS was recorded by using the polaroid prints. The axis of the IVS in the horizontal plane was measured from the recorded polaroid prints. The value of the angularity of IVS (IVS-A) expressed as means +/- one standard deviation (mean +/- 1S.D.) is 52.0 +/- 13.7 degrees in ASD, 42.2 +/- 9.7 degrees in VSD(I), 43.7 +/- 9.1 degrees in VSD(II), 41.6 +/- 11.4 degrees in PDA, 38.6 +/- 10.9 degrees in PS, 61.0 +/- 8.5 degrees in TOF and 40.1 +/- 8.2 degrees in normal controls. There was no significant difference among VSD(I), VSD(II), PDA, PS and normal controls but a highly significant difference was noted in ASD and TOF as compared to other groups. The correlation coefficient of the IVS-A with (1) the Qp/Qs ratio, (2) the magnitude of shunt (%), (3) the right ventricular pressure and (4) the hematocrits were evaluated among the patient groups. The IVS-A of ASD and VSD(II) had a good correlation with the shunt flow (r = 0.921 and 0.88 respectively) and/or the Qp/Qs ratio (r = 0.782 and 0.955 respectively); while that of VSD(I), PDA, and PS had a good correlation with the right ventricular pressure (r = 0.956, 0.953, 0.842 respectively) and that of TOF was mostly concerned with the hematocrits (r = 0.911). Besides, the IVS-A in each severe CHD subgroup was significantly (p less than 0.005 or a better value) higher than the normal control group. Thus an alternative method was validated for evaluating the severity of congenital heart disease by using a noninvasive two-dimensional echocardiographic technique.