Basic and Clinical Analysis of Macroscopic and Microscopic Characteristics of Coronary Circulation in Cardiac Hypertrophy

众所周知，心脏可以通过诱导心肌肥大来适应压力过载或容量过载，从而减轻心肌应激。结果表明，肥厚心脏的冠状动脉储备减少。然而，关于心肌肥厚导致冠状动脉循环恶化的原因报道很少。本研究用20 MHz超声多普勒测速仪测量了心肌肥厚患者的冠状动脉血流，用激光多普勒测速仪测量了犬的心外膜和心肌内动脉血流。我们发现心肌收缩阻碍了冠状动脉的流入，它可能直接影响到心内血管，而心内压的影响相对较小。此外，我们发现心肌肥厚在心脏收缩期存在逆行动脉血流，舒张早期血流减少。这些结果表明，心肌收缩是决定相动脉血流的主要因素，心肌肥厚对冠状动脉循环有复杂的影响。

It is well known that the heart can adapt itself to pressure overload or volume overload by inducing cardiac hypertrophy and thus reducing myocardial stress. Whereas, it is indicated that coronary reserve is decreased in hypertrophied heart. However, only little finding is reported on why coronary circulation is deteriorated in cardiac hypertrophy.In this study we measured coronary artery flow in human being with cardiac hypertrophy by 20 MHz ultrasound Doppler velocimeter, and epicardial and intramyocadial artery flow in dogs by laser Doppler velocimeter.We found that myocardiac contraction impedes coronary inflow and it may affect directly to intramyocardial vessels and the effect of intramyocadial pressure is relatively small. In addition we found that in human cardiac hypertrophy there exists reverse arterial flow in systole and that early diastolic flow is reduced. These findings suggest that myocadial contraction is a major factor determining phasic arterial flow and cardiac hypertrophy has complex effects on coronary circulation.