myocardial bridge
A congenital anatomical variant where a coronary artery segment courses through myocardial tissue rather than along the epicardial surface.
Full Definition
A myocardial bridge is a congenital anatomical variant in which a segment of a coronary artery, most commonly the left anterior descending artery, courses through the myocardium rather than along the epicardial surface. The overlying muscle band compresses the artery during systole, creating a characteristic "milking effect" that can be seen on angiography as systolic compression with diastolic release. While often benign, myocardial bridges can occasionally cause ischemia, particularly during tachycardia when diastolic filling time is reduced. On CT angiography, myocardial bridges appear as segments where the coronary artery is surrounded by myocardial tissue. The hemodynamic significance depends on the length and thickness of the bridge and the degree of systolic compression.
Usage
Usage note: Describe the degree of compression and specify whether hemodynamically significant; distinguish from fixed stenosis.
In Context
- "CT angiography identified a myocardial bridge involving the mid-LAD with 70% systolic compression." — Cardiac CT report
- "Angiography demonstrated the classic milking effect of a myocardial bridge during systole." — Cardiac catheterization report