159 LEFT VENTRICULAR PRESSURE-DIAMETER RELATIONS FOLLOWING ANGIOCARDIOGRAPHY IN CHILDREN

Abstract

The LV pressure-diameter (P-D) relations of 8 children (3 - abnormal LV, 5 - normal LV) were evaluated before and 5 minutes after right heart angiography (preA, postA) using Millar catheter transducer and M-mode echocardiogram. A digitizer interfaced to H-P computer obtained sequential LV diameter, wall thickness and pressure of 4 cardiac cycles. Circumferential wall force (F), meridional wall stress (S), D/P and P/D ratios, dD/dt, dD/dt/D, dF/dt and dS/dt were obtained q 10 msec. Systolic and diastolic segments of P-D, P-S and P-F loops were analyzed. Paired t-test of preA vs postA showed no change in heart rates and endsystolic diameters. However, significant changes were observed postA: LVEDP (+67%, p < .005), LVEDD (+6.6%, p < .01), ejection period (+9.9%, p < .02), peak systolic pressure (+11.5%, p < .01), peak S (+23%, p < .005) and total systolic S (+34%, p < .005). S/unit pressure rise during isovolumic contraction did not change postA. The increase in peak S postA was accompanied by drop in peak dD/dt/D (-31%, p < .05) suggesting decreased pump function despite increased sarcomere length. The diastolic segment of P-F loop characterized early relaxation (E) and later ventricular filling (L). Although diastolic F was higher postA during E and L, the P-D-F relations did not change significantly suggesting unaltered ventricular compliance. The change in LV performance following angiography is related to increased preload plus some reduction of pump function.