Abstract

Rheological properties o f blood were studied in eight patients with dilated cardiomyopathy (DCM) and ten healthy controls . Whole blood viscosity was measured at 4 different shear rates, using a computer controlled rotational viscometer. Patients had significantly higher blood viscosity at all shear rates, both at the patients natural hematocrits and after in vitro adjustment of sample hematocrits to 45%. Erythrocyte filterability measured by St George's Filtrometer and expressed as red cell transit time (RCTT) were significantly lower in patients. Hematocrits were higher but not statistically significant. No differences were found regarding plasma viscosity, leucocyte count and leucocyte filterability. The blood rheology changes found in this study may contribute to myocardial perfusion disturbances, which have been suggested a s a cause for DCM. The coronary blood flow reserve is reduced in patients with DCM as well as in patients with angina pectoris, both with and without coronary artery stenosis (Syndrome X). In all three patients cathegories we have found increased blood viscosity but DCM differs by by normal plasma viscosity.