Named signs in myocardial bridging
There are several named signs in myocardial bridging. Myocardial bridging is usually seen in left anterior descending coronary artery, with a segment of the artery passing beneath a myocardial bridge. It produces narrowing of the coronary artery in systole, which is relieved in diastole. Hence most often it does not compromise the coronary blood flow, which is mostly in diastole.
- “Milking effect” is noted on coronary angiography indicating the systolic compression and diastolic relief of compression
- “Step down-step up” phenomenon can be seen both on coronary angiography still pictures and coronary CT angiography, due to the effect of myocardial bridge on the coronary lumen.
- “Half-moon phenomenon” is noted on intravascular ultrasound. It can occur even without the ‘milking effect’, the milking effect can be provoked in these cases.
- “Fingertip phenomenon” or “spike-and-dome pattern” are descriptions for the intracoronary Doppler flow patterns in myocardial bridging.
1. Möhlenkamp S, Hort W, Ge J, Erbel R. Update on myocardial bridging. Circulation. 2002; 106: 2616–2622.