[Doppler-hemodynamic evaluation of variations in left ventricular filling due to reduction of external mechanical...

It has been recently shown that preload reduction affects the pattern of left ventricular (LV) filling in a way that mimics those Doppler changes that have been associated with impaired LV diastolic function. In order to better relate changes of mitral flow velocity profile to changes of the diastolic properties of the ventricle, in 11 ischemic patients diastolic pressure-volume relations from micromanometer LV pressure and LV volume derived from Doppler and 2D-echocardiography were constructed before and after TNT (0.2 mg iv). TNT induced a significant reduction in LV peak pressure (% change: -13 +/- 7%, p: 0.0003), end-diastolic pressure (EDP) (-62 +/- 45%, p: 0.0006), and constant of isovolumic pressure decay (T) (-8.4 +/- 6.6%, p: 0.012). The left atrial pressure at the time of mitral valve opening (PCO: defined as the pressure at the time of initial transvalvular flow assessed by Doppler) decreased 5.3 +/- 9.6 mmHg (p: 0.11). The early filling E wave of the Doppler velocity profile was significantly reduced by TNT (-20.1 +/- 12.7%, p: 0.0003), while the atrial contribution to total filling increased by 21.3 +/- 29.7% (p: 0.03). The E/A ratio decreased from 0.87 +/- 0.31 to 0.66 +/- 0.22 (p: 0.016), and the change correlated with changes in EDP (p less than 0.05) and PCO (p less than 0.01). The diastolic pressure-volume relationship was displaced downward (p: 0.0007) and minimally leftward (p: 0.45), suggesting relief of external constraint.(ABSTRACT TRUNCATED AT 250 WORDS)