The relationship between cardiac contraction and intramyocardial hemodynamics

Since coronary venous flow is squeezed out from the myocardial vascular bed by the extravascular compressive force of heart muscle, the coronary venous system provides a suitable model to investigate the relationship between cardiac contraction and intramyocardial hemodynamics. To investigate coronary venous flow velocity in more detail, we previously developed a laser Doppler velocimeter (LDV) with an optical fiber. Furthermore, we have recently developed a needle probe charge-coupled device (CCD) videomicroscope to visualize intramyocardial microvessels. In this article, we report I) blood flow velocity waveforms in the epicardial small veins of the left ventricle and 2) subendocardial venular diameter changes during a cardiac cycle.