Background: Patients with mild heart failure show a reduction in preload reserve mechanism during volume expansion. At this time, the effects of volume expansion on left ventricular (LV) diastolic filling in this subset of patients have not been well characterized.
Methods: We evaluated the effects of acute volume loading on Doppler parameters of LV filling in 10 healthy control subjects and in 12 patients with idiopathic dilated cardiomyopathy (DCM). In patients with DCM, the effects of losartan on diastolic adaptation to volume load were also investigated.
Results: During volume loading, the healthy control subjects showed a decrease in isovolumic relaxation time (F = 5.3, P <.05) but an increase in the LV peak filling rate (F = 52.9, P <.001) and velocity time integral of both systolic (F = 72.8, P <.001) and diastolic (F = 4.6, P <.05) pulmonary venous flow. In patients with DCM, isovolumic relaxation time decreased more than in control subjects (F = 8.1, P <.01), and the deceleration time of the early mitral wave was reduced (F = 26.3, P <.001). Furthermore, the duration of pulmonary venous flow reversal exceeded that of mitral flow at atrial contraction (F = 28.5, P <.001). After treatment with losartan, the deceleration time of early mitral wave remained unchanged, and the duration of pulmonary venous flow reversal at atrial contraction did not exceed that of mitral flow; thus, a significant treatment effect was detectable (F = 5.6, P <.05; and F = 6.6, P <.05, respectively).
Conclusions: Control subjects respond to volume load with enhancement in early LV filling, whereas patients with DCM show an increase of LV filling pressure. Diastolic adaptation to volume load improves in patients with DCM after treatment with losartan.