Myocardial bridging of the coronary arteries

Myocardial bridging is a common congenital anomaly of the coronary arteries where a coronary artery courses through the myocardium. 

It is found approximately in 20-30% of the adult population in autopsy studies. Incidence in coronary angiograms is between 2-15%.

Normally major coronary arteries follow an epicardial course throughout their length, but in some cases, segments of the coronary arteries may course intramurally into the myocardium (tunnelled artery). 

Myocardial bridging may be described as:

  • superficial (incomplete)
  • deep (complete)

Bridging is typically described for left anterior descending artery (LAD), with the mid LAD considered the most common location 5, however, other major coronary arteries can also be involved 2.

Myocardial bridging does not produce any symptoms in the majority of patients. However, deeper bridging (>2 mm) may cause symptoms of angina or ischemia in some patients.

  • LAD myocardial bridging can be detected by both angiography and coronary artery MDCT
    • angiographic diagnosis is by demonstrating indirect sign called milking effect
    • coronary artery MDCT directly shows a portion of the artery which is intramyocardial
    • coronary artery MDCT is often better at detecting RCA myocardial bridging
  • the bridged segment often appears to be free of atherosclerosis 5

There are some reports suggesting the efficacy of calcium channel blockers in symptomatic patients 3.

Congenital coronary artery anomalies
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Article information

rID: 25561
System: Cardiac, Vascular
Section: Anatomy
Tag: cases
Synonyms or Alternate Spellings:
  • Tunneled coronary artery
  • Myocardial bridging of coronary arteries
  • Myocardial bridge
  • Tunneled coronary arteries

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Cases and figures

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    Case 1: LAD bridging
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    Case 2: LAD bridging
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