Sakai O, Fujita M, Sasayama S, Asanoi H, Nakajima H, Yokawa S
Second Department of Internal Medicine, Toyama Medical and Pharmaceutical University, Japan.
Jpn Circ J. 1988 Feb;52(2):149-54. doi: 10.1253/jcj.52.149.
We analyzed the effect of xamoterol (beta 1-partial agonist) on myocardial energetics in 8 patients with normal left ventricular function. We measured resting systemic and coronary hemodynamics before and after a single intravenous injection of xamoterol (0.1 mg/kg). This agent increased heart rate from 70 +/- 7 to 80 +/- 11 beats/min (p less than 0.05) and cardiac index from 2.9 +/- 0.5 to 3.2 +/- 0.5 L/min.m2 (p less than 0.01), respectively. Left ventricular peak positive dp/dt (1870 +/- 350 vs 2620 +/- 580 mmHg/sec (p less than 0.01) and left ventricular ejection fraction (62 +/- 7 vs 70 +/- 7% (p less than 0.01] also increased, while left ventricular end-diastolic pressure (9 +/- 3 vs 5 +/- 3 mmHg (p less than 0.01] and volume index (70 +/- 14 vs 58 +/- 16 ml/m2 (p less than 0.01] decreased. Coronary blood flow and total myocardial oxygen consumption did not change significantly after intervention. As a result, xamoterol enhanced left ventricular external mechanical work versus myocardial oxygen consumption ratio (mechanical efficiency) from 20 +/- 4 to 24 +/- 5% (p less than 0.01). Myocardial oxygen extraction ratio decreased significantly (p less than 0.01) from 66 +/- 5 to 62 +/- 5% after xamoterol. We conclude that xamoterol augments left ventricular mechanical efficiency accompanied by a decrease in coronary vascular tone in patients with normal cardiac function.
我们分析了xamoterol（β1部分激动剂）对8例左心室功能正常患者心肌能量代谢的影响。在单次静脉注射xamoterol（0.1mg/kg）前后，我们测量了静息状态下的全身和冠状动脉血流动力学。该药物使心率分别从70±7次/分钟增加至80±11次/分钟（p<0.05），心脏指数从2.9±0.5升/分钟·平方米增加至3.2±0.5升/分钟·平方米（p<0.01）。左心室最大dp/dt（1870±350对2620±580mmHg/秒，p<0.01）和左心室射血分数（62±7对70±7%，p<0.01）也增加，而左心室舒张末期压力（9±3对5±3mmHg，p<0.01）和容量指数（70±14对58±16ml/平方米，p<0.01）降低。干预后冠状动脉血流和心肌总耗氧量无明显变化。结果，xamoterol使左心室外部机械功与心肌耗氧量之比（机械效率）从20±4%提高至24±5%（p<0.01）。xamoterol使用后心肌氧摄取率从66±5%显著降低至62±5%（p<0.01）。我们得出结论，在心脏功能正常的患者中，xamoterol可提高左心室机械效率，并伴有冠状动脉血管张力降低。
