Nitroglycerin-Induced Coronary Collapse in a Patient With Myocardial Bridging

Myocardial bridging (MB) is a congenital anomaly in which a segment of a coronary artery, typically the left anterior descending artery (LAD), courses intramyocardially. Though often benign, MB can cause angina, ischemia, arrhythmias, or acute coronary syndromes. Nitroglycerin, a common treatment for chest pain, may paradoxically worsen MB-related ischemia by enhancing vessel compression during systole.

A 48-year-old woman presented with chest pain and nonsustained ventricular tachycardia. Coronary computed tomography revealed a mid-LAD bridge with dynamic systolic compression. Nitroglycerin worsened stenosis to near-occlusion (99%), which improved after intracoronary nicardipine by 39%. She underwent successful unroofing and left internal mammary artery-to-LAD bypass.

This case underscores the paradoxical effects of nitroglycerin in MB and the need for advanced imaging. Surgical intervention may be warranted in severe, refractory cases. Multidisciplinary management optimizes outcomes.

MB can precipitate ischemia. Nitroglycerin may worsen systolic compression, leading to coronary collapse; prompt diagnosis is critical to achieve optimal outcomes.