[Evaluation of left ventricular diastolic chamber stiffness by the apexcardiogram and echocardiogram]

This study was made to evaluate left ventricular (LV) chamber stiffness noninvasively utilizing the apexcardiogram and echocardiogram. Subjects were 13 patients with left ventricular hypertrophy (LVH) and 17 patients without LVH. Cardiac catheterization and LV angiography were also performed in all patients. In the apexcardiogram, as shown in Figs. 1 and 2, the ratios of an amplitude to the total amplitude were measured at the onset of left atrial systole (H1) (80 msec after the onset of the P wave) and the peak of A wave (H2). In the echocardiogram, LV internal diameters were determined at 80 msec after the onset of the P wave (D1) and the peak of the R wave of ECG (D2). In addition left ventricular volumes, V1 and V2, were calculated by D1 and D2 using Teichholz's method. Increments of the ratio of an amplitude of the ACG wave (delta H = H2-H1) and LV volume changes (delta V = V2-V1) which are associated with left atrial systole were calculated. The ratio of delta H to delta V (delta H/delta V) was defined as a measure of LV diastolic chamber stiffness. On the other hand, various parameters (delta P/delta V, K, dV/dP, dV/VdP) which represent LV diastolic properties were determined by LV pressure curves and LV cineangiograms. delta H/delta V by noninvasive method showed good correlations with delta P/delta V (r = 0.83), K (r = 0.68), dV/dP (r = -0.80) and dV/VdP (r = -0.75), respectively. The correlations were much better between delta H/delta V and these parameters than between A/Eo and these parameters. Patients with LVH had much greater diastolic stiffness (delta H/delta V = 2.03 +/- 1.10) than those without LVH (delta H/delta V = 0.60 +/- 0.29, p less than 0.01). It is concluded that delta H/delta V obtained from ACG and the echocardiogram is a useful parameter to evaluate LV diastolic chamber stiffness noninvasively and this ratio is well correlated with LVH.