Comparison of electrocardiographic findings between Northern and Southern Chinese population samples

Background. Cardiovascular disease is rare in China, but there are few data on the prevalence of electrocardiographic (ECG) abnormalities in Chinese populations. Methods. The ECG surveys were carried out in four Chinese population samples, in a total of 9666 adults aged 35-54 in Beijing and Guangzhou, China from 1981 to 1984. Twelve-lead resting ECG tracings were coded by the Minnesota Code. Results. Prevalence per 1000 of abnormal ECG ranged from 77.4 to 209.8, and was higher for men than women and higher for Guangzhou than Beijing. Prevalence per 1000 of major abnormalities in Guangzhou was 29.8 for men and 78.4 for women, higher than the 18.4 and 29.6 for counterparts in Beijing. The ECG changes attributed in 'Western' populations to coronary heart disease (CHD), such as large Q waves (Minnesota Code 1-1, 1-2) and ST-T abnormalities, were similar between Beijing and Guangzhou men, but Guangzhou women had much higher prevalence of ST-T abnormalities than Beijing women. Other ECG abnormalities such as A-V block, left branch bundle block, and left ventricular hypertrophy were rare in people of both sites. Conclusions. Compared with similar data from the US, these Chinese populations had a relatively low prevalence of ECG abnormalities putatively related to CHD. This corresponds with the low incidence of CHD in the Chinese population. However, within the Chinese populations of this study, a high abnormality rate appeared in a population with low incidence of CHD and hypertension (Guangzhou women). Reasons why ECG abnormalities do not parallel prevalence levels of CHD and hypertension remain to be elucidated.