Although not common or rare, coronary bridging (myocardial bridge) is a congenital anomaly where a band of muscle lies on top of a coronary artery instead of below it. As a result, a portion of the vessel is revealed that dips into and underneath the heart muscle, and then back out again. The vessel is open during diastole (Figure 1) and compressed during systole (Figure 2).
Coronary bridging is most often seen in the middle segment of the left anterior descending (LAD) artery, with patients being asymptomatic or experiencing angina, myocardial ischemia, acute coronary syndrome, left ventricular dysfunction, and arrhythmias. Despite better understanding of this anomaly through imaging technology, treatment options remain limited. Medical therapy with beta blockers and calcium channel blockers are first options. Coronary stenting may result in stent fracture or vessel perforation. Surgical myotomy has been used for refractory cases.
An outpatient 74-year-old Caucasian male presented for cardiac catheterization, with a history of hypertension. He complained of exertional chest discomfort, shortness of breath, and mild palpitations, with his symptoms worsening. He had a normal echocardiogram and left ventricular function was 60%. A Holter monitor and electrocardiogram showed occasional ventricular ectopies and a heart rate of 50-102 beats per minute. No significant valvular disorders were present. A nuclear stress test showed inferior ischemia.
Cardiac catheterization via a radial approach demonstrated minimal non-obstructive coronary artery disease, with a bridging effect in the mid LAD (Figures 1-2, Video 1). Optimizing medical management was the course of treatment.
Author’s note from Bonnie McDonald, RN, CEPS, RCES: “The visual impact of the cardiac cath lab is amazing to me. Being a nurse doing both electrophysiology (my first choice) and cath lab has provided many learning opportunities.”
- Lee MS, Chen CH. Myocardial bridging: an up-to-date review. J Invasive Cardiol. 2015 Nov; 27(11): 521-528