A rare case of myocardial bridging as a cause of complete heart block: A diagnostic challenge

Abstract

Complete heart block (CHB) is a disruption in electrical impulses to travel from atria to ventricles and can rarely be caused by myocardial bridging (MB), where cardiac tissue compresses a coronary artery during systole. The incidence of MB ranges from 0.5 % to 16 % in coronary angiography patients. This case report presents a 30-year-old female presented with dizziness, shortness of breath, and chest pain, diagnosed with third-degree AV block. Echocardiography revealed interventricular septal thickening and mild mitral regurgitation. Coronary angiography identified myocardial bridging in the mid LAD artery causing significant systolic stenosis. After ruling out reversible causes, a dual-chamber permanent pacemaker was implanted due to persistent heart block. The patient remained stable postprocedure, with decreasing cardiac biomarkers, and was discharged symptom-free with a follow-up appointment scheduled. MB can lead to serious cardiovascular events, including myocardial infarction and CHB. Clinicians must recognize the risks associated with MB and maintain a high suspicion for CHB to ensure timely management. Further studies are needed to clarify the CHB-MB relationship and improve patient outcomes.