Changes in ischaemic ECG abnormalities and subsequent risk of cardiovascular disease

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.