The effect of use contrast media on frontal plane QRS-T angle in patients who had elective coronary angiography

Objectives: Electrocardiography (ECG) is a non-invasive, easily accessible and low cost test that has a very important place in the diagnosis and follow-up of cardiovascular diseases. Especially in serial ECG follow-ups, active change monitoring is a finding with diagnostic and prognostic importance. Coronary angiography is the gold standard imaging method in the diagnosis of coronary artery disease. Contrast media is used to visualize the coronary artery lumen in coronary angiography. Contrast media may cause changes in the electrophysiologic properties of the myocardium, which may trigger some changes in the ECG. However, the effects of contrast agent use on ECG are not fully known. Frontal plane QRS-T angle defines the angular difference between depolarization (QRS axis) and repolarization (T axis) vectors, it is an ECG sign of ventricular repolarization heterogeneity. Studies have shown that increased frontal plane QRS-T angle is associated with arrhythmic events and mortality. The aim of our study is to investigate the effect of contrast agent use on frontal plane QRS-T angle in patients undergoing elective coronary angiography. Methods: Our study included 343 patients who were diagnosed with stable angina pectoris and who had coronary angiography in the Cardiology Clinic of Tokat Gaziosmanpaşa University Medical Faculty Hospital between March 2021- July 2022 and met the inclusion criteria. Demographic data and risk factors of all patients were recorded at admission. The routine ECG recordings of the patients included in the study before and after coronary angiography were analyzed. The frontal plane QRS-T angle was calculated from the pre- and post-procedure ECGs of the patients and the change was recorded. The amount of contrast agent used was also noted for each patient. The change in frontal plane QRS-T angle before and after the use of contrast media was investigated. Statistically significant value was accepted as <0.05. Results: The change in frontal plane QRS-T angle was statistically significant after the use of contrast media (30.04±30.76 vs 33.87±32.6, p value <0.001). Among the electrocardiographic parameters of the patients, QTc duration (414.33±18.32 vs. 419.8±19.82, p value = <0.001), Tp-e (73.34±11.8 vs. 78.1±11.88, p value = <0.001), Tp-e/QT ratio (0.19±0.03 vs. 0.2±0.03, p value = <0.001), Tp-e/QTc ratio (0.18±0, 03 vs 0.19±0.03, p value = <0.001), QT dispersion (58.85±18.96 vs 61.44±17.06, p value = <0.001) and QTc dispersion (63.41±) 20.81 vs 68.08±20.01, p value = <0.001) changes were found to be statistically significant. No statistically significant difference was found in QT duration, QRS axis and T axis (p=0.738, p=0.063, p=0.681, respectively). v Conclusion: Our study is the first to evaluate the relationship between contrast media and frontal plane QRS-T angle, which is an indicator of ventricular repolarization heterogeneity, in patients undergoing elective coronary angiography. In our study, a statistically significant change was found in the frontal plane QRS-T angle of the patients after contrast media, regardless of the amount used. Although the amount of this parameter, the predictor of arrhythmia, did not exceed the pathological limits, it can be concluded that the contrast medium given during coronary angiography may increase the risk of arrhythmia and that it is necessary to be prepared for possible malignant ventricular arrhythmias during the procedure. Keywords: Frontal plane QRS-T angle, contrast media, coronary angiography