Relationship between the subendocardial viability ratio and risk factors for ischemic heart disease

Abstract

Ischemic heart disease is one of the major causes of sudden death in Japanese workers. Hypercholesteremia, hypertension, obesity, and the smoking habit are considered to be risk factors for cardiovascular events. Generally the subendocardium is thought to be more sensitive to a shortage of blood supply than the subepicardium. Buckberg et al. have demonstrated that the ratio of the area of the diastolic phase (diastolic pressure time index: DPTI) to that of the systolic phase (time tension index: TTI) in the central aortic profile has a close correlation with the blood supply to the subendocardium. This ratio was designated as the subendocardial viability ratio: SEVR (DPTI/TTI). We examined the relationships between the SEVR, as measured by SphygmoCor (AtCor Medical Ltd.), and the data from the health examination of 178 males working for a steel company. A significantly low SEVR was observed in people with the smoking habit, a high pulse rate, obesity, abnormality of blood fat components, or hyperglycemia. Employees in the normal SEVR group (SEVR: 140% or more) n = 120 and low SEVR group (SEVR: 139% or less) n = 58 were compared. The results suggested that employees with low SEVR were older and had a higher BMI, higher pulse rate, higher total cholesterol, higher triglyceride, and higher fasting plasma glucose. They also had lower HDL-cholesterol. In the low SEVR group, the percentage of employees with hyperlipidemia or hyperglucosemia was significantly higher than that in the normal SEVR group. Results of stepwise regression analysis indicated that the pulse rate and age were significant and independent predictive factors for SEVR. These data on SEVR calculated from the wave pattern of the central artery are considered to be useful parameters for evaluating the risk of myocardial ischemia and for guiding health promotion.