Case report: Myocardial bridge as cause of STEMI-pattern ECG after supraventricular tachycardia

Abstract

Background

Myocardial bridging (MB) is a congenital coronary anomaly typically considered benign. However, under conditions of increased myocardial demand—such as supraventricular tachycardia (SVT)—MB can lead to transient ischemia or infarction. This case highlights a rare presentation of MB mimicking a left main coronary syndrome following SVT.

Case report

A 36-year-old male with no reported past medical history presented to a rural critical access hospital with palpitations after playing basketball and drinking two energy drinks. On arrival, he was afebrile with a heart rate of 208 bpm but was otherwise stable. ECG revealed narrow-complex tachycardia, which resolved after a modified Valsalva maneuver. Post-conversion ECG showed sinus rhythm with marked ST elevation in aVR and diffuse ST depressions. A repeat ECG 20 minutes later showed resolution of the ST changes. Labs were unremarkable aside from significant troponin elevation. Echocardiogram was normal. Cardiac catheterization revealed no obstructive coronary disease but did identify a myocardial bridge over the mid-LAD with moderate systolic compression. The patient was discharged without medications and later underwent ablation for SVT.

Why should an emergency physician be aware of this?

Myocardial bridging should be considered in patients with transient ischemic ECG changes post-SVT, especially when coronary angiography is unrevealing. ED recognition of MB may prevent unnecessary thrombolysis or catheterization and guide appropriate follow-up.