OBJECTIVE: To visualize epicardial and intramyocardial coronary blood flow by using a noninvasive echocardiography system. METHODS: In five juvenile swines, coronary flow imaging was used to visualize the different segments of epicardial coronary and intramyocardial arteries. Pulsed-Doppler spectrums were recorded and analyzed. The left anterior descending artery (LAD) and intramyocardial coronary blood flow signals were recorded at baseline and during dipyridamole administration. RESULTS: Epicardial and intramyocardial coronary arteries could be visualized by coronary flow imaging. The systolic component of coronary flow in the right coronary artery (RCA) was greater than in the LAD. The intramyocardial blood flow was characterized by persistent retrograde blood flow velocity during systole. Vasodilation with dipyridamole produced exaggerated differences in the phasic pattern of coronary blood flow in epicardial and intramyocardial vessels. CONCLUSION: Color Doppler coronary flow imaging provides a noninvasive method to study the coronary blood flow.
