Demonstration of pathologic coronary artery flow using transthoracic Doppler echocardiography

Using a high frequency transducer with special setting of low Nyquist limits, the pathologic coronary artery flows were demonstrated as follows: 1) Retrograde coronary artery flow on transthoracic Doppler echocardio-graphy suggested the filling via collateral circulation in the total occlusion of left anterior descending coronary arteries (LAD). 2) Not only the abnormally low velocity but also the abnormally high velocity suggested the pathologic conditions of coronary artery at resting. Furthermore, slow flows less than 13cm/s predicted the severe and diffuse atherosclerotic narrowing of LAD or microvascular dysfunction in normal coronary artery. 3) Diastolic dominant coronary flow pattern at anastomosis site predicted the patent graft vessels. 4) Diastolic duration of coronary artery flow was significantly shortened in left bundle branch block (LBBB).