Effects of negative T wave in electrocardiography on prognosis of post-myocardial infarction patients.

Background: Negative T (NT) wave in electrocardiography (ECG) is one of the important factors in determining short- and long-term outcomes in patients with acute myocardial infarction (MI). In this study, we compared clinical and paraclinical findings in post-MI patients according to presence or absence of NT wave.

Methods: A cross-sectional study was conducted on patients with acute ST elevation MI who presented to Shahid Modares Hospital (Tehran, Iran) during 2009-10. After undergoing streptokinase therapy, demographic characteristics and ECG and exercise test findings of the subjects were compared based on the presence or absence of NT wave.

Results: Overall, 116 patients including 69 cases with NT wave (NT group) and 47 cases without NT wave (PT group) were enrolled (mean age: 53.7 ± 7.1 vs. 54.1 ± 6.8 years old). Mortality rate during the first five days was 13% in the NT group and 29% in the PT group (P < 0.05). Ejection fraction values of the NT group were significantly higher than the PT group (P = 0.005). However, left ventricular end-diastolic diameter of the NT group was significantly less than the PT group (P = 0.005). Moreover, ST segment depression was significantly less frequent in the NT group compared to the PT group.

Conclusion: Patients with ST elevation MI accompanying with NT wave in ECG versus have better prognosis and myocardial function than similar patients without NT wave. Therefore, invasive procedures should be recommended for patients without NT wave.