QT change before and after coronary angiography in patients with myocardial infarction

ECG is a rapid, low-cost, easily accessible, and reproducible diagnostic method for the evaluation of patients presenting with chest pain in the emergency department. The aim of this study was to investigate the relation of QTc interval prolongation, ST segment depression, T wave negativity and electrical axis changes observed in ECGs taken in the emergency department with the clinical course and coronary angiography results in patients with MI. In addition, the relationship between these changes and the treatment modalities (medical therapy or percutaneous coronary intervention) was evaluated. Method: Patients aged between 18 and 100 years who were diagnosed with myocardial infarction and followed up in the Emergency Department of Van Yüzüncü Yıl University Faculty of Medicine between 20/05/2024 and 20/05/2025 were included in this study. Age, gender, diagnostic information, medications used and ECG findings of the patients were obtained from nurse observation forms, patient files and hospital data recording system. The first and second ECGs of all patients on admission to the emergency department and ECGs obtained after PCI were analyzed. QTc duration, cardiac electrical axis, ST segment depression and T wave negativity were measured. Pre- and post-PCI data were compared and differences in QTc change, axis shifts, ST segment changes and T wave negativity were analyzed. Results: The study included 109 patients. 69.7% (n=76) of the patients were male and 30.3% (n=33) were female. The mean age of the patients was 62±10.68 years. There was a prolongation of QTc in the ECGs of the patients from pre- to post-angiography and there was a significant difference between QTc at diagnosis and QTc after PCI in our study. Although there was a significant difference in T wave negativity, there was no significant difference in ST depression. The axis of 40.4% of the patients was deviated to the left and 52.3% of the patients were deviated to the right. The axis change was significant in pre-angiography compared to post-angiography. In patients with LMCA, LAD or Cx lesions, the axis usually deviated to the left; in patients with RCA or concomitant vessel involvement, the axis deviated to the right. However, there was no significant difference between treatment modality and axis changes. When QTc was compared according to treatment modality, no significant change was found in the medical treatment group, while a decrease in QTc values was observed in patients who underwent angioplasty, but it was not significant (p=0.086). A significant difference was obtained when T negativity at post angiography was compared with the treatment modality. According to treatment modality, the most common vessel to undergo PCI was RCA (26.6%), followed by Cx (23.9%) and LAD (22.9%). Medical treatment was administered to 20.2% of the patients because severe vessel occlusion was not detected. Conclusion: In this study, a significant difference was found between QTc at diagnosis and QTc after PCI. A prolongation of the QTc interval was observed in patients in whom vessel occlusion was detected compared to patients in whom occlusion was not detected and who received medical treatment after angiography. In addition, the axis of the heart shifted to the right if the treated vessel was RCA and deviated to the left if it was LAD and/or CX. T wave negativity, QTc interval and electrical axis monitoring may provide important information in the evaluation of treatment response and prediction of prognosis in patients. Especially in elderly patients, diabetic patients or patients presenting with atypical symptoms, these ECG parameters can be used as a supportive tool in early decision making and rapid guidance processes. It is of great importance to accelerate patient circulation in the emergency department and to shorten the time of admission to the coronary intensive care unit and transportation to the angiography unit. Since heart attack is a complex and dynamic process, timely identification of PCI candidates is essential for early reperfusion interventions. Therefore, more widespread and effective use of non-invasive diagnostic methods should be encouraged.