Determinants of global left ventricular peak diastolic filling rate during rest and exercise in normal volunteers

Early peak diastolic filling rate (PFR) of the left ventricle (LV) is said to be a sensitive index of LV dysfunction in patients with coronary disease, hypertension and hypertrophic cardiomyopathy. Radionuclide (RN0 multigated PFR was measured in 20 normal volunteers (13 males, 7 females, mean age 31 yrs., range 20-43) at rest and during supine bicycle exercise conducted to a symptomatic end-point. At rest, RN PFR was 3.4 +- SD 0.4 end-diastolic vols./sec (range 3.1 - 3.6). During exercise all normal volunteers had a progressive and numerically and statistically significant increase in PFR. Stepwise multiple linear regression (BMPD2R) was applied to the rest and exercise PFR data to develop a linear model describing the main determinants of the RN PFR. The potential independent variables which were included in the model were heart rate (HR), ejection fraction (EF), systolic arterial pressure, systolic ejection rate and exercise stage. Ranking of variables for prediction of RN PFR, and exclusion of less important variables, was done by F value criteria. The final multivariate equation was: LVPFR = -3.84437 + 0.03834 HR + 0.07537 LVEF. The model fit was highly significant (p<0.001), and accounted for 89 per cent of variability in the PFR. The authors conclude that the left ventricular peak filling rate is critically determined by heart rate and by ejection fraction at rest and during exercise