Auerbach I, Tenenbaum A, Motro M, Stroh C I, Har-Zahav Y, Fisman E Z
Cardiac Rehabilitation Institute, Sheba Medical Center, Tel-Hashomer, Israel.
J Heart Lung Transplant. 2000 Nov;19(11):1063-70. doi: 10.1016/s1053-2498(00)00204-7.
Relatively light isometric exercise (handgrip) in heart transplant recipients induces attenuated increments in heart rate, blood pressure, and systemic vascular resistance, but hemodynamic response to whole-body, heavy isometric exercise is unknown. The aim of our study was to investigate the influences of whole-body, heavy, isometric exercise on Doppler-derived parameters in these patients.
We investigated 18 patients, aged 54.0 +/- 2 years, 1.6 +/- 1.0 years after cardiac transplantation and 18 sedentary healthy volunteers, aged 51.8 +/- 4 years (p = not significant). Patients performed supine, isometric exercise by stretching a whole-body isometric device at 50% of maximal voluntary contraction for 3 minutes.
Resting heart rate, blood pressure, and rate-pressure product were higher in transplanted patients when compared with the healthy volunteers (p < 0.001 for all). However, during isometric exercise, these parameters increased to a lesser extent in the transplanted compared with the healthy subjects-heart rate, 12% vs 40% (p < 0.001); mean arterial pressure, 20% vs 27% (p < 0.05); and rate-pressure product, 39% vs 85% (p < 0.001). In the healthy volunteers, peak-flow velocity, mean acceleration, flow-velocity integral, and stroke volume decreased by 30% to 40% with isometric exercise (p < 0.001 for all), whereas systemic vascular resistance increased by 36% (p < 0.001) and cardiac output did not change. In the transplanted patients, all above parameters remained unchanged. Heavy, whole-body isometric exercise was well tolerated in heart transplant recipients in this study, without hemodynamic deterioration or other complications.
With whole-body, heavy isometric exercise, Doppler-derived aortic flow parameters demonstrate blunted responses or remain unchanged among heart transplant recipients. The observed phenomenon may have implications for studies of exercise physiology in transplant recipients.
心脏移植受者进行相对轻度的等长运动（握力运动）时，心率、血压和全身血管阻力的增加幅度减弱，但全身重度等长运动的血流动力学反应尚不清楚。我们研究的目的是调查全身重度等长运动对这些患者多普勒衍生参数的影响。
我们调查了18例患者，年龄为54.0±2岁，心脏移植后1.6±1.0年，以及18名久坐不动的健康志愿者，年龄为51.8±4岁（p无显著性差异）。患者通过拉伸全身等长装置以最大自主收缩力的50%进行仰卧位等长运动3分钟。
与健康志愿者相比，移植患者的静息心率、血压和心率-血压乘积更高（所有p<0.001）。然而，在等长运动期间，与健康受试者相比，移植患者这些参数的增加幅度较小——心率，12%对40%（p<0.001）；平均动脉压，20%对27%（p<0.05）；心率-血压乘积，39%对85%（p<0.001）。在健康志愿者中，等长运动时峰值流速、平均加速度、流速积分和每搏输出量降低了30%至40%（所有p<0.001），而全身血管阻力增加了36%（p<0.001），心输出量未改变。在移植患者中，上述所有参数均保持不变。在本研究中，心脏移植受者对重度全身等长运动耐受性良好，无血流动力学恶化或其他并发症。
对于全身重度等长运动，心脏移植受者的多普勒衍生主动脉血流参数显示反应迟钝或保持不变。观察到的现象可能对移植受者运动生理学的研究有影响。
