Análise quantitativa do eletrocardiograma normal e isquêmico para o desenvolvimento de um escore preditor da área miocárdica em risco de necrose

Abstract

The electrocardiogram (ECG) is widely used in clinical practice, especially for the identification of cardiac diseases. Due to the ethnic differences that exist in several populations, specific values for the normal ECG are not necessary in agreement with standard values presented in the literature. For this reason, it was performed a clinical study of the Brazilian normal ECG, leading to results that does not agree with the standard literature. In addition, high incidence of Acute Myocardial Infarction (AMI) in the Brazilian population motivated the quantitative analysis of ECG change, particularly the ST deviation. The methods for the estimation of the myocardial risk area (i.e., the myocardial area under risk of necrosis if the AMI progresses) were studied, mainly the Aldrich score, which may be calculated from the ECG. This study included both Brazilian and Danish patients. For the Brazilian patients, biochemical markers of the myocardial necrosis, troponin T and of CKMB, were used as gold standards; whereas single-photon-emission-computed tomography (SPECT) was employed as gold standard for the Danish patients. Based on the drawbacks of these scores, which were assessed both from the literature as well as from the experimental results that was obtained in this research, a new score was proposed based on the concept of ST segment deviation area, including the T wave (ST-T). This new score was applied to both populations, leading to higher correlations with the respective gold standard patterns, especially for inferior AMI and for Brazilian patients.