Symptomatic proximal left anterior descending artery myocardial bridging near a diagonal branch origin: a rare case report

Background: Myocardial bridging (MB) is a congenital coronary anomaly in which an epicardial artery courses within the myocardium. It most commonly involves the mid-left anterior descending (LAD) artery, while proximal LAD involvement at the LAD–diagonal bifurcation is rare and may carry greater hemodynamic significance. Case presentation: A 23-year-old male presented with persistent retrosternal chest pain. Vital signs revealed elevated blood pressure, while electrocardiography and serial high-sensitivity troponins were normal. Despite initial symptomatic relief with nitrates, the patient developed recurrent exertional chest pain, unresponsive to further nitrate therapy. Coronary angiography demonstrated marked systolic compression at the proximal LAD–diagonal bifurcation, consistent with MB. The patient was treated with beta-blocker therapy, resulting in partial symptomatic improvement. Conclusion: Proximal LAD MB at a bifurcation is an uncommon but clinically significant variant that may cause ischemic symptoms despite normal biomarkers. Worsening of symptoms with nitrates reflects the underlying pathophysiology and should raise clinical suspicion. Beta-blockers remain the preferred first-line therapy. Early recognition of this variant is essential in young patients presenting with unexplained chest pain, particularly in the presence of a relevant family history.