Very early risk stratification by electrocardiogram at rest in men with suspected unstable coronary heart disease. The RISC Study Group.

OBJECTIVES

To determine the possibility of very early prognostic stratification based on electrocardiograms (ECGs) at rest and/or cardiac enzyme levels after an episode of suspected unstable coronary heart disease.

DESIGN AND SETTING

Men with suspected unstable angina or non-Q-wave myocardial infarction were studied in the coronary care units of eight hospitals. The ECGs at rest and creatinine kinase were followed.

SUBJECTS

In total 911 men were followed for 12 months. Of 8136 consecutively admitted, 3365 fulfilled the inclusion criteria. Excluded were 2454 patients, mainly because of a larger myocardial damage, signs of myocardial dysfunction, other serious cardiac or non-cardiac disease or an ECG not possible to interpret regarding ST-T-segment changes in the precordial leads.

MAIN OUTCOME MEASURES

End-points at follow-up were cardiac death, myocardial infarction and severe (class III or IV) angina.

RESULTS

Compared to patients with normal a ECG who had an 8% 1-year risk of myocardial infarction or death, the risk with isolated negative T waves was 14% (P < 0.05), ST elevation 16% (P < 0.05), ST depression 18% (P < 0.01) and the combination of ST elevation and ST depression 26% (P < 0.001). The only finding related to future severe angina was ST depression. The risk of cardiac events was comparably elevated in patients with anterior or inferior site of ECG changes. Cardiac enzyme levels had no predictive value regarding future events.

CONCLUSIONS

Electrocardiograms at rest obtained during the initial days of hospitalization provide very early and valuable prognostic information in men admitted with suspected unstable coronary heart disease.