Discrepancy between stress electrocardiographic changes and nuclear myocardial perfusion defects in the prognostic assessment of patients with chest pain

The aim of the present study was to determine the long-term prognostic value provided by the exercise electrocardiographic (ECG) response to nuclear myocardial perfusion imaging (MPI) in the evaluation of patients with chest pain, focusing on patients with a discrepancy between the two tests. A total of 1460 consecutive patients (777 female; 62.6±11.4 years) undergoing exercise myocardial single-photon emission computed tomography (SPECT) were included. The endpoint was the occurrence of acute coronary syndrome, heart failure or cardiac death during follow-up. Ischemic ECG changes were observed during stress testing in 271 patients (18.5%) and 362 patients (24.7%) had positive (abnormal) exercise MPI results. There was a discrepancy between ECG and SPECT findings in 471 patients (32.2%). During the follow-up period (14.0-39.6 months), 224 patients (15.3%) presented cardiac events. The hazard ratios (HR) of ECG and MPI results to predict events were 1.506 (95% CI: 1.113-2.039) and 10.481 (95% CI: 7.799-14.080), respectively. In patients with negative MPI, the ECG response did not predict events (HR 1.214 [95% CI: 0.646-2.282]), the same as in patients with positive MPI (HR 1.203 [95% CI: 0.848-1.705]). Only in hypertensive patients with positive SPECT did the ECG show significant prognostic value (HR 1.937 [95% CI: 1.030-3.642]). In multivariate analysis, positive MPI proved an independent long-term prognostic factor (HR 10.536 [95% CI: 7.759-14.308]), but not ECG (HR 1.356 [95% CI: 0.994-1.850]). MPI results (normal vs. abnormal) had strong predictive value and discrepant ECG results had no significant additive prognostic value. O objetivo do presente estudo foi determinar o valor prognóstico a longo prazo, fornecido pelo eletrocardiograma (ECG) em resposta ao esforço na cintigrafia de perfusão miocárdica (CPM) na avaliação de doentes com dor torácica, com ênfase para os grupos de doentes com discrepância entre os dois testes. Foram incluídos 1460 doentes consecutivos (777 do sexo feminino; 62,6 ± 11,4 anos), submetidos a exercício na cintigrafia de perfusão miocárdica com SPECT. O endpoint foi a presença de síndrome coronária aguda, insuficiência cardíaca ou morte cardíaca durante o seguimento. Duzentos e setenta e um doentes (18,5%) apresentaram alterações eletrocardiográficas de isquemia durante o teste de esforço e 362 doentes (24,7%) tinham resultados positivos (anormais) na CPM. A discrepância entre os resultados do ECG e CPM apareceu em 471 doentes