Jan et al. (1975) measured blood viscosity in patients having heart attacks (acute myocardial infarction) on the day of hospital admission, then again 3 and 21 days after. They found that patients with higher blood viscosity on admission had significantly more medical complications. These complications were shock, thromboembolism, and left ventricular failure. They also found that blood viscosity remained high 21 days after heart attack in spite of a fall in packed cell volume.
Malkun Paz et al. (1987) measured blood viscosity in 25 patients with heart disease. They reported that both blood viscosity levels were elevated independent of the packed cell volume.
Schabitz et al. (1977) and Schabitz and Krosch (1979) compared blood viscosity of healthy adults with that of 63 patients with chronic heart disease after heart attack. The blood viscosity levels of the patients after heart attacks were significantly higher than that of the healthy adults, and blood viscosity was positively correlated with packed cell volume and concentrations of cholesterol, total lipids, and fibrinogen.