The effects of chronic hypoxia on left ventricular peak filling rate evaluated by equilibrium radionuclide angiocardiography.

Left ventricular peak filling rate (PFR) was measured by equilibrium radionuclide angiocardiography (ERNA) in 15 patients with Stage II stabilized chronic respiratory failure (CRF) without evidence of coexisting heart diseases and in 18 patients with coronary artery disease (CAD) without myocardial infarction. The study was designed to assess the effects of severe hypoxia and of ischaemia on the calcium-dependent early diastolic filling. PFR was found to be impaired in both groups of patients (mean = 1.72 EDVs-1 and S.E.M. = 0.07 in CAD; mean = 2.35 EDVs-1 and S.E.M. = 0.14 in CRF) but significantly less (p less than 0.001) in CRF patients while the left ventricular ejection fraction (LVEF) values were not significantly different between the two groups (mean = 60.0% and S.E.M. = 1.4 in CAD; mean = 62.0% and S.E.M. = 1.6 in CRF). As PFR is known to be a sensitive index of left ventricular performance the results obtained in this human model are consistent with findings obtained in animal models suggesting that hypoxia is less efficient than ischaemia in depressing left ventricular function.