Nitroglycerin-Induced Coronary Collapse in a Patient With Myocardial Bridging.

BACKGROUND

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.

CASE SUMMARY: 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.

DISCUSSION: 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.

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