Steding-Ehrenborg Katarina, Hedén Bo, Herbertsson Pär, Arheden Håkan
Department of Clinical Physiology, Lund University, Skåne University Hospital, Lund, Sweden.
Clin Physiol Funct Imaging. 2013 Nov;33(6):423-30. doi: 10.1111/cpf.12048. Epub 2013 Apr 29.
Studies of cardiovascular deconditioning are primarily carried out after experimental bed rest. No previous study has followed the cardiovascular effects of decreased and resumed physical activity in athletes after acute physical injury and convalescence. Anterior cruciate ligament (ACL) injury causes a significantly decreased activity level over a long period, making it an ideal model for studying effects of deconditioning and reconditioning. Therefore, the aim of this study was to investigate how cardiac dimensions and maximal exercise capacity change after an ACL-injury.
Seventeen athletes (5 women) were included. Cardiac magnetic resonance (CMR) was performed within 5 days of the injury (CMR1), before endurance training was resumed (CMR2) and 6 months after the second scan (CMR3). Maximal exercise testing was performed on the same day as CMR2 and 3.
The deconditioning phase between CMR1 and CMR2 was 59 ± 28 days. Total heart volume (THV) decreased with -3·1 ± 6·7%, P = 0·056. Between CMR2 and 3 (reconditioning), THV increased significantly (2·5 ± 4·6%, P<0·05). Left and right ventricular EDV decreased during deconditioning (-3·0 ± 5·6% and -4·7 ± 6·6%) and increased during reconditioning (1·7 ± 3·9% and 2·6 ± 6·2%) however not statistically significant. Left ventricular mass (LVM) remained unchanged. VO2 peak (mlmin(-1) kg(-1) ) increased significantly during the reconditioning phase (6·1 ± 5·3%, P<0·001).
Physiological cardiac adaptation to deconditioning and reconditioning caused by severe knee injury with maintained normal daily living during convalescence was smaller than previously shown in bed rest studies. Total heart volume and VO2 peak were significantly affected by reconditioning whilst LVEDV, RVEDV and LVM remained unchanged over the study period.
心血管去适应研究主要在实验性卧床休息后进行。此前尚无研究追踪急性身体损伤及康复后运动员身体活动减少和恢复时的心血管效应。前交叉韧带（ACL）损伤会导致长期活动水平显著下降，使其成为研究去适应和再适应效应的理想模型。因此，本研究旨在调查ACL损伤后心脏大小和最大运动能力如何变化。
纳入17名运动员（5名女性）。在受伤后5天内（CMR1）、恢复耐力训练前（CMR2）以及第二次扫描后6个月（CMR3）进行心脏磁共振成像（CMR）检查。在与CMR2和CMR3同一天进行最大运动测试。
CMR1和CMR2之间的去适应阶段为59±28天。全心容积（THV）下降了-3.1±6.7%，P = 0.056。在CMR2和CMR3之间（再适应阶段），THV显著增加（2.5±4.6%，P<0.05）。去适应期间左、右心室舒张末期容积（EDV）下降（-3.0±5.6%和-4.7±6.6%），再适应期间增加（1.7±3.9%和2.6±6.2%），但无统计学意义。左心室质量（LVM）保持不变。在再适应阶段，峰值摄氧量（VO2峰值，ml·min⁻¹·kg⁻¹）显著增加（6.1±5.3%，P<0.001）。
在康复期间日常生活保持正常的情况下，因严重膝关节损伤导致的去适应和再适应过程中，生理性心脏适应比此前卧床休息研究显示的要小。再适应对全心容积和VO2峰值有显著影响，而在研究期间左心室舒张末期容积、右心室舒张末期容积和左心室质量保持不变。
