Martisiene I, Gendviliene V, Zablockaite D, Gurskaite H
Institute of Cardiology, Kaunas University of Medicine, Lithuania.
Rocz Akad Med Bialymst. 2005;50:241-3.
The purpose of present study was to investigate the effect of metabolic substrate pyruvate and beta-adrenergic agonist isoproterenol and combination of these agents on the force- and relaxation-frequency relationship in human heart failure.
The experiments were performed on isolated human ventricle strips from patients undergoing cardiac corrective open heart surgery, using conventional method of registration of electromechanical activity. The stimulation frequency of myocardial strips was 0.2, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 Hz.
In control, i.e. at perfusion of myocardial strips by Tyrode solution and stimulation frequency 1 Hz, the contraction force (F) was 0.94 +/- 0.18 mN, half time of relaxation (tr)--178.8 +/- 9.3 ms (n= 12). Pyruvate (10 mmol/L) increased F to 176.0 +/- 13.4%, tr--104.6 +/- 3.1% (n=8, p<0.05) vs control. By the action of isoproterenol (10(-5) mol/L) F increased to 122.1 +/- 10.2%, tr decreased to 58.9 +/- 3.1% (n=4, p<0.05) vs control. The relationship of F and tr from stimulation frequency in the absence of pyruvate and isoproterenol was negative. Pyruvate and isoproterenol didn't alter the shape of force-frequency relationships but F was augmented at all stimulation frequencies. The positive inotropic effect of isoproterenol was potentiated by pyruvate.
Pyruvate and isoproterenol alone can improve cardiac contractility in wide-range of stimulation frequency. The combination of these inotropic agents results in even more effective increase of contractile performance and therefore may be of therapeutic value in heart failure.
本研究旨在探讨代谢底物丙酮酸、β - 肾上腺素能激动剂异丙肾上腺素以及这两种药物联合使用对人心力衰竭时力 - 频率和舒张频率关系的影响。
实验采用常规的机电活动记录方法，在接受心脏直视矫正手术患者的离体人心室条上进行。心肌条的刺激频率为0.2、0.5、1.0、1.5、2.0、2.5和3.0赫兹。
对照组中，即在用台氏液灌注心肌条且刺激频率为1赫兹时，收缩力（F）为0.94±0.18毫牛，舒张半衰期（tr）为178.8±9.3毫秒（n = 12）。丙酮酸（10毫摩尔/升）使F增加至176.0±13.4%，tr为104.6±3.1%（n = 8，p < 0.05），与对照组相比。异丙肾上腺素（10⁻⁵摩尔/升）作用后，F增加至122.1±10.2%，tr降至58.9±3.1%（n = 4，p < 0.05），与对照组相比。在不存在丙酮酸和异丙肾上腺素时，F与刺激频率的tr关系为负相关。丙酮酸和异丙肾上腺素未改变力 - 频率关系的形状，但在所有刺激频率下F均增加。丙酮酸增强了异丙肾上腺素的正性肌力作用。
丙酮酸和异丙肾上腺素单独使用均可在较宽的刺激频率范围内改善心脏收缩力。这些正性肌力药物联合使用可更有效地增加收缩性能，因此可能对心力衰竭具有治疗价值。
