ABSTRACT
Myocardial bridging is a systolic compression(milking effect) of mainly the left anterior descending coronary artery with coronary angiography. This phoenomenon is known to occur when a segment of an artery travels through the myocardium. The function significance of this finding remains controversial. We identified angiographic systolic compression of the coronary artery in two patients and documented the coronary flow velocity patterns and coronary flow velocity reserve with intracoronary injection of adenosine. The intracoronary flow velocity patterns distal to the myocardial bridging segment of the left anterior descending artery show the attenuated systolic component and abnormal diastolic flow velocity pattern with the exaggerated early acceleration, a diastolic spike and dome shape of coronary flow. The coronary flow velocity reserve was reduced.