Abstract
The purpose of this study was to evaluate the role of the diastolic pressure-volume relationship of the right ventricle. Twenty-four patients consisting of 4 with normal hemodynamics, 11 with heart diseases and 9 with pulmonary diseases were studied. Ages ranged from 17 to 76 years. Right heart catheterization was performed in all cases and the right ventricular residual ratio (RVRR) was measured by the RI method.
Patients with heart and pulmonary diseases had nearly the same degree of mild to moderate pulmonary hypertension at the time of this study. Passilve elastic modulus (k) was calculated from right ventricular endo-diastolic volume and pressure by the formula P=bekV (Gaasch). dV/dP (cc/m2/mmHg)=e-kV/kb or 1/kP and dV/Vdp (mmHg-1) =dV/dP 1/V were also calculated.
Passive elastic modulus of cases with normal hemodynamics was 0.023±0.003, heart diseases 0.018±0.002 and pulmonary diseases 0.014±0.002. The k value was significantly different between normal hemodynamics and pulmonary diseases (p<0.01). The values of dV/dP and dV/VdP in cases with pulmonary diseases tend to be high. value Correlation between k and paO2 (r=0.440, p<0.05), k and stroke index (r=-0.451, p<0.05), and k and right ventricular work index (r=-0.670, p<0.01) respectively were significant. Furthermore, the correlation between paO2 and RVRR (r=-0.625, p<0.01) was also significant.
These results suggest that in cases with pulmonary diseases the right ventricle was compelled to perform less effective pumping function both in systole and diastole phase because of increased compliance of the right ventricle probably due to chronic hypoxia. This fact was further supported by acutely induced hypoxia test.
