Blood Flow Dynamics of Left Coronary Artery in Hypertrophied Human Heart

为探讨左室肥厚时左冠状动脉血流速度波形的特点，应用80通道20 MHz脉冲多普勒血流速度计，分析主动脉瓣置换术前后主动脉瓣关闭不全和狭窄患者左前降支（LAD）血流速度的时相波形，在主动脉瓣关闭不全时，左前降支（LAD）的血流特征为收缩期血流增加，舒张期血流减少，幅度小而迅速。通过起搏增加心率导致收缩期血流减少和舒张期血流成分增加。主动脉瓣置换术后，收缩期血流减少36.3 ± 21.7%，而舒张期血流明显增加81.4 ± 51.8%。这些发现表明，主动脉瓣反流和主动脉瓣置换术中心率的增加 ...更多信息 主动脉瓣狭窄时左前降支血流速度波形特征为收缩期反向血流和舒张期缓慢增加的血流。所有患者的舒张期峰值速度（T-DPV）从开始使用阿托洛尔的时间延长，并且在起搏心率增加后没有变化。在120起搏频率下，舒张期血流频谱发生明显变化，即舒张期血流峰值与随后收缩期QRS波群重叠，舒张期血流迅速减少。这些结果表明，心率的增加导致冠状动脉血流量显着减少主动脉瓣狭窄。主动脉瓣置换术后舒张期血流增加率增加，T-DPV由176.8 ± 28.8 cm/s缩短至90.5 ± 18.8 cm/s。此外，舒张期峰值流速从90.5 ± 28.0 cm/s增加到122.5 ± 17.2 cm/s。这些变化表明主动脉瓣狭窄切除术对人体冠状动脉流入的有益影响。少

To clarify the characteristics of the left coronary blood flow velocity wave forms in left ventricular hypertrophy, we analyzed phasic flow velocity wave forms of left anterior descending coronary artery (LAD) in the patients with aortic regurgitation and stenosis before and after aortic valve replacement using an 80-channel 20 MHz pulsed Doppler velocimeter, and the influence of increase in heart rate on the velocity wave forms was studied by atrial pacing during cardiac operations.In aortic regurgitation, the LAD flow was characterized by an increase in the systolic flow component, a small and rapidly decreased diastolic flow. An increase in heart rate by pacing brought about a decrease in systolic flow and an increase in diastolic flow component. After aortic valve replacement, systolic flow decreased by 36.3 + 21.7%, whereas diastolic flow markedly increased by 81.4 + 51.8%. These findings suggest that the increase in heart rate in aortic regurgitation and aortic valve replacement … More induce beneficial effects on the myocardial inflow.The LAD flow velocity wave form in aortic stenosis was characterized by a reverse flow in systole and a slowly increasing diastolic inflow. The time from onset of diastole to the diastolic peak velocity (T-DPV) lengthened in all patients and did not change after an increase in heart rate by pacing. The apparent changes in diastolic flow pattern were observed at the pacing rate of 120, that was, the peak region of diastolic flow velocity overlapped with QRS of subsequent systole, therefore, increasing diastolic inflow rapidly decreased. These findings suggest that the increase in heart rate brings about markedly decrease in coronary blood flow in aortic stenosis. After aortic valve replacement, the increasing rate of the diastolic inflow was augmented and T-DPV was shortened from 176.8 + 28.8 to 90.5 + 18.8 cm/s. In addition, the diastolic peak velocity increased from 90.5 + 28.0 to 122.5 + 17.2 cm/s. These changes suggest the beneficial effects of removal of aortic stenosis on human coronary artery inflow. Less