The relationship between myocardial bridge and frontal QRS-T angle

Although Myocardial bridge (MB) is known as a benign condition, it has been demonstrated to be associated with cardiac arrhythmias and poor outcomes. Frontal QRS-T angle (fQRSTa) is a novel indicator of repolarization and depolarization heterogeneity. Last studies indicated that associated with fQRSTa and adverse cardiac events. No study evaluated the relationship between fQRSTa and MB. In the present study, we aimed to investigate the relationship between MB and fQRSTa.

This study included 91 patients with normal coronary arteries and 89 patients with MB. Coronary angiography was performed in all patients due to ischemia findings on treadmill exercise test or myocardial scintigraphy.2-lead surface electrocardiograms (ECGs) of all patients were evaluated. QT interval, fQRSTa, QTc interval were measured from surface ECGs.

Baseline clinical, echocardiographic and laboratory parameters were similar between MB and control group. However, when compared to control group, patients with MB had importantly raised fQRSTa [27 (20-41) vs. 23 (12-37) p = 0.007]. In correlation analysis, fQRSTa was positively correlated with MB length (r = 0.411, p < 0.001). Linear regression analysis showed that MB length was the just considerable predictor of fQRSTa (β = 0.247, p = 0.041).

The fQRSTa is a novel electrocardiographic marker that can be easily obtained from surface ECG. We have shown for the first time that MB length is a significant predictor of fQRSTa.