The importance of a normal ECG in non-ST elevation acute coronary syndromes

Abstract Background: Admission ECG has a major impact on the diagnosis and management of non-ST elevation acute coronary syndromes (ACS).Purpose: To assess the impact of the admission ECG on prognosis over non-ST ACS.Population: Prospective, continuous, observational study of 80 non-ST ACS patients from a single center. Patients were divided in  groups: A (n=58) – Abnormal ECG and B (n=64) – Normal ECG. Normal ECG was synonymous of sinus rhythm and no acute ischemic changes. A one-year clinical follow up was performed targeting all causes of mortality and the MACE rate.Results: Group A patients were older (68.7 ± .7 vs. 6.4 ± .7Y, p<0.00), had higher Killip classes and peak myocardial necrosis biomarkers. Furthermore, they had lower left ventricular ejection fraction (LVEF) (5.0 ± 0.55 vs. 55.4 ± 9.5%, p<0.00), glomerular filtration rate, initial hemoglobin, and total cholesterol levels. Group B patients were more frequently submitted to invasive strategy (6.6 vs. 46.5%, p<0.00) and treated with aspirin, clopidogrel, beta blockers and statins. They also more often presented normal coronary anatomy (6. vs. 8.0%, p=0.45). There was a trend to higher in-hospital mortality in group A (4.6 vs. .9%, p=0.054). Kaplan-Meyer analysis showed that at one month and one year (95. vs. 89.5%, p=0.0) survival was higher in group B and the result remained significant on a Cox regression model (normal ECG HR 0.45 (0. – 0.97). There were no differences regarding the MACE rate.Conclusion: In our non-ST elevation ACS population, a normal ECG was an early marker for good prognosis. (Arq Bras Cardiol 00; 94() : 4-)Key Words: Electrocardiography; Diagnostic; Reference Standards; Prognosis.