[The changes of electrocardiogram and impact of early invasive strategy in patients with acute coronary syndromes without ST-segment elevation].

OBJECTIVE: To investigate the changes of electrocardiogram (ECG) and impact of early invasive strategy in patients with acute coronary syndrome (ACS) without ST-segment elevation.

METHODS: Five hundred and forty-five consecutive ACS patients without ST-segment elevation were randomly assigned to early conservative treatment group and early invasive treatment group. The combined cardiovascular events, including cardiac death, nonfatal myocardial infarction, nonfatal heart failure, and re-hospitalization due to recurrent ischemia angina, within 30 days and 6 months were analyzed and the effects of varied ECG changes and different intervention strategies on outcomes of patients were evaluated.

RESULTS: The incidences of each and combined cardiovascular events were higher in the patients with ST-segment depression than in those without ST-segment depression. ST-segment depression was one of independent predictive factors for an increase in cardiovascular events within 6 months (OR 3.864, 95% CI: 1.668 approximately 9.451, P < 0.001). Early invasive strategy was associated with a lower rate of re-hospitalization due to recurrent ischemia angina within 30 days and a decreased incidence of combined cardiovascular events within 30 days and 6 months in comparison with the early conservative treatment group (all P < 0.05). Subgroup analysis implied that incidences of combined cardiovascular events within 30 days and 6 months decreased significantly only in patients with ST-segment depression treated with early invasive strategy, and no such benefit was seen in the patients without ST-segment depression.

CONCLUSION: ST-segment depression is an effective indicator for identifying those patients with non-ST segment elevation ACS most likely to benefit from early invasive strategy. Early invasive strategy markedly decreases the cardiovascular events in ACS patients with ST-segment depression than early conservative strategy.