Ischemic profile and cardiovascular function in African men : the SABPA study

Thesis (M.Sc. (Physiology))--North-West University, Potchefstroom Campus, 2012.Motivation: Ischemic heart disease is the eighth leading cause of death in an African population. Silent ischemia can be defined as an ischemic episode without associated pain. The clinical significance of silent ischemia is growing and can now be considered as a risk factor in the development of coronary disease. Hypertension and associated risk factors, hypercholesterolemia and diabetes are associated with silent ischemia. Other factors such as higher pulse pressure, double product, heart rate and higher carotid intima-media thickness are also associated with silent ischemia. Urbanisation is rising in South-Africa. This new lifestyle is associated with several risk factors including: poor diets, lower physical activity levels, hypertension and increased smoking and alcohol abuse. The prevalence of stroke is high among Africans, which can be due to a higher prevalence of hypertension, diabetes and obesity. Purpose: The purpose of this study was to determine the associations between silent ischemia and cardiovascular function in African men. The focus fell on hypertension and associated risk factors, higher total cholesterol levels, and increased pulse pressure, heart rate and sub-clinical atherosclerosis. Methodology: This study constituted a population study in the North-West province carried out on urbanized African male teachers aged between 20-60 years. The SABPA (Sympathetic activity and Ambulatory Blood Pressure in Africans) sub-study consisted of a total of 80 African male volunteers. The Cardiotens apparatus was placed on each participant on the first morning. This apparatus took ambulatory blood pressure measurements as well as Electrocardiogram measurements. Hereafter, participants continued with their normal work day until 1700. After an overnight stay at the Metabolic unit of the North-West University Potchefstroom campus, the apparatus was removed at 0600. During statistical analyses, the African males were divided into groups of participants with silent ischemia (SI) and those without silent ischemia (nSI), as determined by the ambulatory electrocardiogram. Statistical analyses were performed by means of the Statistica version 10 software program. Results: In comparison with the nSI men, the SI showed the following: above normal high sensitivity C-reactive protein and glucose, higher ambulatory blood pressure, heart rate, pulse pressure, resting ST-segment depression and carotid intima-media thickness. Multiple regression analyses indicated that ambulatory silent ischemia is associated with sub-clinical atherosclerosis, possibly increasing their stroke risk.Master