Abstract
A myocardial bridge (MB) is an anatomical variant in which the myocardial muscle partially covers the epicardial coronary arteries, in particular, the left anterior descending coronary artery (LAD). Although this variant has been considered clinically benign, it can lead to significant clinical issues, such as arrhythmia, myocardial ischemia, conduction disturbances, myocardial infarction and sudden death in a subset of patients. Autopsy and CT studies have identified MB in ~ 25% of patients, whereas only 10% of patients have angiographically detectable systolic compression. Intravascular imaging is more sensitive than angiography for detecting minor MB compression.
Imaging and autopsy studies have shown a greater plaque burden in the LAD segment proximal to the MB than within the tunneled LAD segment, and this can be associated with a series of severe cardiovascular events. In general, symptomatic patients should be treated conservatively with medical management comprising beta-blockers and non-dihydropyridine calcium-channel blockers to reduce arterial compression by the muscular band and slow the heart rate, thereby increasing the diastolic period. Various strategies including surgery have been attempted to treat refractory symptoms, depending on the status of patients.
