Effect of acute angiotensin converting enzyme inhibition on left ventricular filling in patients with congestive heart failure. Relation to right ventricular volumes.

To examine the manner in which changes in diastolic performance can contribute to the effect of vasodilation in patients with left ventricular (LV) systolic dysfunction, we examined the effect of acute inhibition of angiotensin converting enzyme with intravenous enalaprilat on early LV diastolic filling. We studied 43 patients with congestive heart failure and depressed LV systolic function (mean ejection fraction +/- SD, 0.24 +/- 0.06), performing radionuclide ventriculography before and after administration of 1.25 mg intravenous enalaprilat. We measured the effect of enalaprilat on the maximum rate of early LV diastolic filling normalized in four different ways and related these changes to both LV and right ventricular (RV) volumes. Enalaprilat induced a small but statistically significant reduction in LV end-systolic volume and increase in LV ejection fraction. For the entire patient group, there was no significant change in LV peak filling rate after enalaprilat administration. For individual patients, however, the effect of enalaprilat on peak filling rate was related to resting RV end-diastolic and end-systolic volumes. In patients with enlarged RV end-diastolic volumes (greater than or equal to 120 ml/m2), mean peak filling rate increased from 1.38 +/- 0.6 to 1.71 +/- 0.6 end-diastolic volumes (EDV)/sec and from 244 +/- 131 to 297 +/- 162 ml/sec/m2 after enalaprilat administration, whereas no change in mean peak filling rate was observed in patients with nondilated RVs. These observations were present regardless of the method of normalizing peak filling rate. Thus, the response of LV peak filling rate to enalaprilat is influenced by the presence of RV dilatation.(ABSTRACT TRUNCATED AT 250 WORDS)