Objective: The prognostic importance of changes in ischaemic ECG abnormalities over time (especially ST-T abnormalities) among Asians has not been fully investigated. We examined the associations between changes in ischaemic abnormalities upon serial ECG (improvement, persistence, deterioration) and cardiovascular disease (CVD) risk.
Methods: A prospective study cohort was conducted with 9374 men and women aged 40-69 years in four communities. Participants had multiple ECGs at study entry and during the next 10 years, and were followed up for a median period of 23.0 years. Total CVD (stroke and coronary heart disease) was ascertained under systematic surveillance. ECG abnormalities were defined by the Minnesota Code, ST depression (Code4), abnormal T wave (Code5) and categorised into nine groups (no-no, no-minor, no-major, minor-no, minor-minor, minor-major, major-no, major-minor, major-major) by comparison with the point of entrance and maximum change.
Results: We documented 1196 CVD events. Compared with no-no abnormality, no-minor, minor-major and major-major in Code4, HRs (95% CI) adjusted for cardiovascular risk factors were 1.19 (1.00-1.42), 1.57 (1.15-2.12) and 1.87 (1.42-2.47). Similar results were observed in Code5.
Conclusions: Changes in ischaemic ECG abnormalities from none to minor, and minor to major, as well as persistent major abnormalities, were associated with an increased risk of CVD.