The Relationship Between Myocardial Bridge and Electrocardiographic Tp-e Interval, Tp-e/QT and Tp-e/ QTc Ratio

Aim: Myocardial bridge (MB) is generally known as an asymptomatic and benign anomaly, however, it can cause serious clinical conditions such as exercise-induced ventricular tachycardia and sudden death. Tp-e interval is the distance between the peak and the end of the T wave in electrocardiography. Tp-e/QT and Tp-e/QTc ratios are used as electrocardiographic indicators of ventricular arrhythmias. We have studied the effect of coronary angiographic features (the degree of stenosis and length of MB) of MB on myocardial repolarization parameters. Methods: The study group consisted of 53 patients with isolated MB and 58 patients with normal coronary arteries. Results: The QT interval and QTc were similar between the groups, however, Tp-e interval (92.72±14.72 and 79.59±12.12, respectively; p<0.001) and Tp-e/QT (0.24±0.041 and 0.21±0.025, respectively; p<0.001) and Tp-e/QTc (0.22±0.037 and 0.19±0.025, respectively; p<0.001) ratios were found to be significantly increased in MB group compared to the control group. In the comparison of the MB patients with critical and those with noncritical stenosis, Tp-e interval (100.69±10.79, 80.57±11.25, respectively; p<0.001) and Tp-e/QT (0.266±0.033, 0.219±0.037, respectively; p<0.001) and Tp-e/QTc (0.244±0.029, 0.196±0.027, respectively; p<0.001) ratios were higher in the MB with critical stenosis group. Conclusion: Our results indicate that these parameters can be practical ECG markers of ventricular arrhythmias in patients with MB.