Severity‐Dependent Myocardial Deformation in Patients With Myocardial Bridging Assessed by Speckle‐Tracking Echocardiography

BACKGROUND: Myocardial bridging (MB) is a congenital coronary anomaly characterized by systolic compression of an intramyocardial coronary artery segment. Although often considered benign, MB may be associated with altered coronary hemodynamic and regional myocardial dysfunction. Speckle-tracking echocardiography (STE) allows sensitive assessment of myocardial deformation and may detect subtle abnormalities not evident with conventional echocardiographic parameters. This study aimed to evaluate myocardial deformation in patients with MB and to investigate the relationship between bridge severity and strain parameters. METHODS: Patients with MB identified by coronary angiography between 2010 and 2022 were retrospectively analysed. Only patients with isolated mid-left anterior descending artery MB and no significant coronary artery disease were included. Patients were categorized according to the degree of systolic narrowing as mild (<50%, group I) or moderate-severe (≥50%, group II). Control subjects had normal coronary angiograms without MB. Conventional echocardiographic parameters and STE-derived global longitudinal strain (GLS) and segmental strain values were compared among groups. RESULTS: Ninety-seven subjects were included (62 with MB and 35 controls). LVEF and overall GLS were similar between MB patients and controls. However, GLS differed significantly across control, group I, and group II (-19.6 ± 2.1%, -20.4 ± 1.9%, and -18.0 ± 3.2%, respectively; p = 0.001). Patients with moderate-severe MB demonstrated less negative strain values in multiple myocardial segments, whereas strain parameters were comparable between controls and mild MB. CONCLUSION: Moderate-severe MB is associated with regional myocardial deformation abnormalities. STE may provide additional functional insight into myocardial mechanics in hemodynamically significant MB.