Coronary myocardial bridge: an innocent bystander?

Myocardial bridge (MB) or tunneled coronary artery is an inborn abnormality, which implicates a systolic vessel compression with a persistent mid-late diastolic diameter reduction. Myocardial bridges are often observed during coronary angiography with an incidence of 0.5%-5.5%. The most involved coronary artery is the left anterior descending artery followed by the diagonal branches, the right coronary artery, and the left circumflex. The overall long-term prognosis is generally benign. However, several risk or precipitating factors (e.g., high heart rate, left ventricular hypertrophy, decreased peripheral vascular resistance) may trigger symptoms (most frequently angina). Herein, we describe two cases of symptomatic myocardial bridge, where medical treatment (i.e., inotropic negative drug) and coronary stenting were successfully utilized to treat this pathology. We also focus on the clinical presentation, and the diagnostic and therapeutic modalities to correctly manage this frequently observed congenital coronary abnormality, underlining the fact that in cases of typical angina symptoms without any significant coronary artery disease, MB should be considered as a possible differential diagnosis.