Hoppeler H, Hess O M, Hug R, Turina J, Krayenbühl H P
Department of Internal Medicine, University Hospital, Zurich, Switzerland.
J Cardiovasc Pharmacol. 1990;15 Suppl 1:S79-83.
The effect of two calcium antagonists on left ventricular (LV) relaxation and diastolic filling was evaluated in 16 randomized patients. Isradipine and nifedipine were administered intravenously in a maximum dose of 60 micrograms/min for isradipine and 63 micrograms/min for nifedipine. Heart rate was increased significantly (p less than 0.01) by both study agents. LV end-diastolic pressure remained unchanged whereas peak systolic pressure decreased significantly (p less than 0.01). The reduction in systolic pressure was significantly greater (p less than 0.05) after isradipine (delta P of 30 mm Hg) than after nifedipine (delta P of 13 mm Hg). The time constant decreased from 65 to 56 ms (p less than 0.05) after isradipine and from 62 to 59 ms (NS) after nifedipine. LV filling remained unchanged. It is concluded that both calcium antagonists are associated with a significant reduction in LV afterload accompanied by a reflex increase in heart rate. Isradipine is a more potent vasodilator than nifedipine at the same infusion rate. A beneficial effect on LV relaxation with isradipine, but not nifedipine, may be due to its less pronounced negative inotropic effect or its more potent afterload-reducing action.
在16例随机分组的患者中评估了两种钙拮抗剂对左心室（LV）舒张及舒张期充盈的影响。以最大剂量静脉注射伊拉地平，剂量为60微克/分钟，硝苯地平为63微克/分钟。两种研究药物均使心率显著增加（p<0.01）。左心室舒张末期压力保持不变，而收缩压峰值显著降低（p<0.01）。伊拉地平（收缩压下降30 mmHg）后收缩压的降低幅度显著大于硝苯地平（收缩压下降13 mmHg）（p<0.05）。伊拉地平后时间常数从65毫秒降至56毫秒（p<0.05），硝苯地平后从62毫秒降至59毫秒（无统计学意义）。左心室充盈保持不变。结论是两种钙拮抗剂均与左心室后负荷显著降低及心率反射性增加有关。在相同输注速率下，伊拉地平是比硝苯地平更强效的血管扩张剂。伊拉地平对左心室舒张有有益作用，而硝苯地平则无，这可能归因于其不太明显的负性肌力作用或更强效的后负荷降低作用。
