Hayashi H, Iwase M, Aoki T, Yokota M
First Department of Internal Medicine, Nagoya University School of Medicine, Japan.
Cardiovasc Drugs Ther. 1990 Aug;4 Suppl 5:969-75. doi: 10.1007/BF02018302.
To evaluate the left ventricular functional changes induced by acute decreases in blood pressure in 15 patients with systemic hypertension and left ventricular hypertrophy, this study used Doppler and M-mode echocardiographic derived left ventricular indices. After 30 minutes of administration of sublingual nifedipine, both systolic and diastolic blood pressure decreased and heart rates increased. The left ventricular end-systolic dimension decreased but not the end-diastolic dimension, which suggests that sublingual nifedipine may decrease only afterload, not preload. Total peripheral resistance decreased from 2770 to 1960 dyne.sec.cm-5. The M-mode-derived peak rate of dimension changes improved both the systolic and diastolic phase, and Doppler-derived indices of atrial contribution to ventricular filling decreased. Because both the systolic and diastolic phase indices of LV function are sensitive to variations in both preload and afterload, the improvement of myocardial contractility per se cannot necessarily be attributed to the direct effect of the drug to myocardium. Though favorable effects on the myocardial oxygen supply-demand ratio or increased adrenergic tone stimulated by the decline in systemic arterial pressures may contribute to the augmentation of LV systolic and diastolic function observed after nifedipine in the present study, the apparent augmentation of LV function appears to be attributable primarily to afterload reduction.
为评估15例系统性高血压合并左心室肥厚患者血压急性下降所引起的左心室功能变化，本研究采用多普勒和M型超声心动图得出的左心室指标。舌下含服硝苯地平30分钟后，收缩压和舒张压均下降，心率增加。左心室收缩末期内径减小，但舒张末期内径未减小，这表明舌下含服硝苯地平可能仅降低后负荷，而非前负荷。总外周阻力从2770降至1960达因·秒·厘米⁻⁵。M型超声心动图得出的内径变化峰值速率在收缩期和舒张期均有所改善，且多普勒得出的心房对心室充盈贡献的指标下降。由于左心室功能的收缩期和舒张期指标均对前负荷和后负荷的变化敏感，因此心肌收缩力本身的改善不一定归因于药物对心肌的直接作用。尽管本研究中硝苯地平治疗后对心肌氧供需比的有利影响或系统性动脉压下降刺激的肾上腺素能张力增加可能有助于左心室收缩和舒张功能的增强，但左心室功能的明显增强似乎主要归因于后负荷的降低。
