Objective The main objective of this study was to estimate the prevalence of coronary heart disease (CHD) of high-altitude populations in Nepal determined by an ECG recordings and a medical history.
Methods We carried out a cross-sectional survey of cardiovascular disease and risk factors among people living at four different altitude levels, all above 2800 m, in the Mustang and Humla districts of Nepal. 12-lead ECGs were recorded on 485 participants. ECG recordings were categorised as definitely abnormal, borderline or normal.
Results No participant had Q waves to suggest past Q-wave infarction. Overall, 5.6% (95% CI 3.7 to 8.0) of participants gave a self-report of CHD. The prevalence of abnormal (or borderline abnormal) ECG was 19.6% (95% CI 16.1 to 23.4). The main abnormalities were: right axis deviation in 5.4% (95% CI 3.5 to 7.7) and left ventricular hypertrophy by voltage criteria in 3.5% (95% CI 2.0 to 5.5). ECG abnormalities were mainly on the left side of the heart for Mustang participants (Tibetan origin) and on the right side for Humla participants (Indo-Aryans). There was a moderate association between the probability of abnormal (or borderline abnormal) ECG and altitude when adjusted for potential confounding variables in a multivariate logistic model; with an OR for association per 1000 m elevation of altitude of 2.83 (95% CI 1.07 to 7.45), p=0.03.
Conclusions Electrocardiographic evidence suggests that although high-altitude populations do not have a high prevalence of CHD, abnormal ECG findings increase by altitude and risk pattern varies by ethnicity.
- CORONARY ARTERY DISEASE
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Contributors All authors contributed to study design. NA collected the data, performed statistical analysis and prepared the first draft of the manuscript. YKDB helped with data collection and MW helped with the statistical analysis. SM reviewed and interpreted the ECG reports. All authors contributed intellectually to the revision of the article and approved the final version.
Funding Capital Cardiovascular Research Trust, Wellington, New Zealand provided funding for the study as well as provided financial support for PhD study of NA at the University of Otago, Wellington, New Zealand.
Competing interests None declared.
Ethics approval University of Otago, Human Ethics Committee; Nepal Health Research Council.
Provenance and peer review Not commissioned; externally peer reviewed.
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