Borrelli Emma, Pogliaghi Silvia, Molinello Alessandro, Diciolla Francesco, Maccherini Massimo, Grassi Bruno
Department of Surgery and Bioengineering, Policlinico, University of Siena, Siena, Italy.
Med Sci Sports Exerc. 2003 Nov;35(11):1798-804. doi: 10.1249/01.MSS.0000093610.71730.02.
Serial evaluation of aerobic metabolism and exercise tolerance early after heart transplantation (HT).
Fifteen heart transplant recipients (HTR), aged 52.0 +/- 9.9 yr (mean +/- SD), not undergoing structured rehabilitation programs, were tested two to four times during the first 2 yr post-HT. As a reference, a group of 11 healthy untrained controls (C) was utilized. Peak heart rate (peak HR), peak O2 uptake (peak VO2), and ventilatory threshold (VT) were determined during incremental bicycle exercise to voluntary exhaustion. VO2 kinetics were evaluated during constant-load exercise below VT, with determination of the duration of the "cardiodynamic" component (TDp) and of the time constant of the "primary" component (taup).
Peak VO2 (L.min-1) was positively related to months post-HT (y=1.17 + 0.02x, P=0.003), and it increased by approximately 30% during the investigated period, although values in HTR were lower than in C (2.19 +/- 0.24). Peak HR was lower in HTR (136 +/- 15 beats.min-1) than in C (168 +/- 5), and it was not related to time post-HT. TDp was longer in HTR (31.4 +/- 6.3 s) than in C (23.2 +/- 6.1), and it was not related to time post-HT. A subgroup of HTR with markedly longer taup during the first months post-HT showed a significant decrease of this parameter as a function of time post-HT.
Aerobic metabolism is impaired in HTR. Both central (cardiovascular) and peripheral (skeletal muscle) factors contribute to the reduced exercise tolerance. HTR showed, during the first 2 yr post-HT, a significant increase in peak VO2 and (in the patients with the slowest VO2 kinetics during the first months after HT) a significant improvement of the VO2 kinetics. The main gains seem to occur at the peripheral level.
对心脏移植（HT）术后早期的有氧代谢和运动耐力进行系列评估。
15名心脏移植受者（HTR），年龄52.0±9.9岁（均值±标准差），未参加结构化康复计划，在HT术后的头2年接受了2至4次测试。作为对照，使用了一组11名健康的未经训练的对照者（C）。在递增式自行车运动至自愿疲劳期间测定峰值心率（peak HR）、峰值摄氧量（peak VO2）和通气阈值（VT）。在低于VT的恒负荷运动期间评估VO2动力学，测定“心脏动力学”成分的持续时间（TDp）和“主要”成分的时间常数（taup）。
峰值VO2（L·min⁻¹）与HT术后的月数呈正相关（y = 1.17 + 0.02x，P = 0.003），并且在研究期间增加了约30%，尽管HTR的值低于C组（2.19±0.24）。HTR的峰值HR（136±15次·min⁻¹）低于C组（168±5），且与HT术后时间无关。HTR的TDp（31.4±6.3秒）比C组长（23.2±6.1），且与HT术后时间无关。HT术后头几个月taup明显更长的HTR亚组显示该参数随HT术后时间显著下降。
HTR的有氧代谢受损。中枢（心血管）和外周（骨骼肌）因素均导致运动耐力降低。HTR在HT术后的头2年显示峰值VO2显著增加，并且（在HT术后头几个月VO2动力学最慢的患者中）VO2动力学有显著改善。主要改善似乎发生在外周水平。
