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Heart Diseases - Diagnosis Evaluation of Chest Pain and Diagnosis of CHD Clinical evaluation of chest pain and establishment of the diagnosis of CHD in blacks is often difficult. Electrocardiographic (ECG) changes long accepted as common “normal variants” in blacks may have greater clinical significance when the increased prevalence of out-of-hospital death, LVH, and hypertension in blacks is taken into account. Coronary spasm and silent ischemia have become established clinical entities. Preliminary findings suggest that there may be racial or ethnic differences in the occurrence and manifestations of these clini-cal syndromes. The advent of ambulatory ECG and blood pressure monitoring has facilitated greater understanding of these syndromes and circadian variation in coronary syndromes in general.Clinical studies suggest that the sensitivity and specificity of tests established in the white popula-tion may differ for blacks. Cardiac diagnostic accu-racy and reliability have not been validated in blacks to the same extent as in whites with respect to risk assessment, therapeutic responses, prognosis, natural history, and long-term health outcomes. For example, echocardiography has provided a link between structural and functional measurements and epidemiological data, but its value in assessing the risk and prognosis of CHD, independent of LVH, has not been fully elucidated in blacks. Limited available data show higher rates of normal coronary angiograms in blacks with chest pain than in whites, raising the possibility of abnormalities in the coronary microcirculation or in vascular tone. However, existing angiographic data on blacks may not be representative because blacks are known to have reduced access to cardiac diagnostic proce-dures. In addition, newer imaging techniques, such as perfusion scintigraphy, intravascular ultrasound, nuclear magnetic resonance (NMR), and positron-emission tomography (PET), have not been ade-quately studied in blacks. Evaluation of Chest Pain and Diagnosis of CHD The clinical evaluation of chest pain continues to challenge the diagnostic acumen of many clinicians. Accurate diagnosis of CHD in blacks may be more demanding because of the more common concur-rence of hypertension, LVH, or both. How this information affects the diagnostic approaches of clinicians is not clear. It is known, however, that blacks receive cardiac procedures, both diagnostic coronary angiography and revascularization, less commonly than whites.It is not clear whether this disparity between blacks and whites is a function of physician factors, limited access to health care, or individual health care seek-ing behavior. Providers may vary in their ability to convey educational messages to culturally diverse patient populations. Research on the roles of these factors is recommended. Studies are also needed to compare the decision-making process by health care providers for ordering diagnostic procedures in blacks and whites and the role of patient preferences in choosing to accept rec-ommended procedures. The relative roles of risk factors, disease severity, and other variables should be compared with the impact of race and socioeco-nomic status on the use of cardiac procedures in blacks. Additional new and improved noninvasive tech-niques for monitoring the development, progression, and regression of CHD and LVH in blacks need to be developed. The implications of ECG findings considered to be normal in blacks should be reassessed, given the data indicating that out-of-hospital deaths and sudden death may be more common in blacks. Comparison of the relative value of imaging techniques for assessing CHD risk in blacks with signal-averaged ECG and other evolving noninvasive techniques should be undertaken. Also important is comparison of the relative value, reliability, accuracy, sensitivity, and specificity of noninvasive diagnostic techniques, such as ECG, echocardiography, stress testing (in conjunction with ECG, echocardiographic, or radionuclide imaging), NMR, and PET, in blacks and whites. The applica-bility of these tests to individuals with atherosclerot-ic and nonatherosclerotic CHD, and with hyperten-sion and/or LVH, should be compared in blacks and whites. Research establishing the role of genetics in some forms of LVH suggests the need to determine the value of echocardiography and other imaging tech-niques, compared with genetic testing, in diagnosing individuals with genetically determined LVH or hypertrophic cardiomyopathy. Clinical trials will be important in evaluating the value of new and improved noninvasive diagnostic tools, such as intravascular ultrasound and three-dimensional echocardiography, in assessing ventricular structure and function and the physiology of the macrovascu-lature in blacks and whites. The reason(s) for the paradoxically high rates of nor-mal coronary angiographic findings in blacks with angina-like chest pain need to be elucidated. Also, given that individuals who enter angiographic trials may not be representative of the general black popu-lation, methods need to be developed to assess and control for selection bias in angiographic studies of blacks. Investigators are encouraged to assess the relationship of coronary angiographic findings to the site of coronary occlusion, extent and severity of myocardial damage, and recurrence and outcomes of CHD events in blacks compared to whites. |
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