Research Group in Heart Valve Diseases, Laval Hospital Research Center, University Laval, Quebec, Canada.
Med Sci Sports Exerc. 2009 Jun;41(6):1230-8. doi: 10.1249/MSS.0b013e318195b938.
Aortic valve regurgitation (AR) imposes a pathologic volume overload to the left ventricle (LV), whereas aerobic exercise causes physiologic volume overloading. The impact of combining both LV volume overloads (pathologic and physiologic) is unknown. Considering the known beneficial effects of aerobic training on the cardiovascular system, we hypothesized that the positive effects would outweigh the negative ones and that exercise would improve the tolerance of the LV to AR.
Forty female adult Wistar rats were randomly divided in the following groups: 1) sham sedentary (SS), 2) sham trained (ST), 3) AR sedentary (ARS), and 4) AR trained (ART). Training consisted in treadmill running for 30 min five times per week at 20 m x s(-1) for 24 wk. In vivo follow-up was made by echocardiography and invasive intracardiac pressure measurements. Hearts were harvested for tissue analysis.
Echocardiography revealed less LV dilation and hypertrophy in ART versus ARS as well as improved myocardial performance index. LV ejection fractions remained similar and within normal range in ART versus ARS. Invasive cardiac pressures yielded improved dP/dt- in ART versus ARS but similar dP/dt+. beta(1)-Adrenergic receptor mRNA expression was improved in the ART group versus ARS.
Our data suggest that a moderate aerobic exercise program helps minimize LV dilation and hypertrophy and improves diastolic cardiac performance in heart submitted to chronic volume overload due to severe aortic valve regurgitation in this animal model.
主动脉瓣反流（AR）会对左心室（LV）造成病理性容量超负荷，而有氧运动则会导致生理性容量超负荷。同时存在这两种 LV 容量超负荷（病理性和生理性）的影响尚不清楚。鉴于有氧运动对心血管系统的已知有益影响，我们假设积极影响将超过消极影响，并且运动将提高 LV 对 AR 的耐受性。
40 只成年雌性 Wistar 大鼠被随机分为以下组：1）假手术安静组（SS），2）假手术训练组（ST），3）AR 安静组（ARS）和 4）AR 训练组（ART）。训练包括在跑步机上以 20 m x s(-1)的速度每周 5 次，每次 30 分钟，持续 24 周。通过超声心动图和侵入性心内压测量进行体内随访。收获心脏进行组织分析。
超声心动图显示，与 ARS 相比，ART 组的 LV 扩张和肥大程度较小，心肌性能指数得到改善。ART 组的 LV 射血分数与 ARS 组相似且仍在正常范围内。与 ARS 相比，ART 组的 dp/dt-有所改善，但 dp/dt+相似。与 ARS 相比，ART 组的β1-肾上腺素能受体 mRNA 表达得到改善。
我们的数据表明，适度的有氧运动方案有助于最大限度地减少因严重主动脉瓣反流导致的慢性容量超负荷的 LV 扩张和肥大，并改善心脏舒张性能。在这种动物模型中。
