Myocardial bridging in an adult patient with d-transposition of the great arteries.

Myocardial bridging is characterized by intra-myocardial course of a segment of an epicardial coronary artery, leading to systolic compression. In most cases, it is considered a benign condition but rarely has been associated with serious cardiac events like myocardial infarction and sudden death. We describe a 25-year-old man with known d-transposition of the great arteries (d-TGA) status post-Mustard procedure who presented with palpitations and chest pain. Cardiac catheterization revealed complete systolic compression of a myocardial bridging segment of the left anterior descending artery and also complete compression of the first septal perforator during episodes of ectopic atrial tachycardia. No percutaneous or surgical interventions were performed. Symptoms improved after cautious use of beta-blockers. This appears to be the first report of symptomatic myocardial bridging in an adult patient with d-TGA.