超声心动图运动负荷实验对优秀耐力运动员左室功能的评定

Echocardiographic Assessment of Left Ventricular Function of Well-trained Endurance Athletes at Rest and During Dynamic Exercise

本文对30名男性优秀耐力运动员和30名健康无训练者在安静时和卧位逐级蹬车负荷(100瓦、150瓦、200瓦、250瓦,每级负荷3分钟)中进行了超声心动图研究。耐力组的舒末内径(LVIDd)和心搏量(SV)无论是在安静时还是在各级等量负荷中,均显著性地大于对照组(P<0.01)。随着负荷量的递增,对照组的LVIDd逐渐减小(P<0.01),耐力组的LVIDd则逐渐地增加(P<0.05)。直到250瓦负荷时才略有下降;两组的左室缩末内径均逐渐缩小,但以对照组缩小的更为明显。低强度负荷(100瓦和150瓦)时,两组的SV均较安静时增大,但在高强度负荷时.耐力组SV继续增高,对照组SV则急剧减少。低强度负荷时,两组的心输量(CO)呈平行增加,高强度负荷时,耐力组CO的增长明显大于对照组。说明有训练的耐力运动员的心力储备优于无训练者。两组的EF、mVcf和△D％以类似的方式随负荷的增加而增加。安静及各级等量负荷状态下组间比较均无显著性差异,提示有氧训练似乎对心脏收缩性无明显影响。笔者认为,动力性运动负荷中的超声心动图检查对于评价运动员左室功能是十分有用的。

M-mode echocardiograms at rest and during supine graded cycling workload (100, 150, 200, 250 watts, each phase lasting 3minutes)were performed in 30 male well-trained endurance athletes and 30 male healthy untrained subjects. Echocardiographic comparisons between the two groups, both at rest and during supine cycling, confirmed that athletes had significantly greater left ventricular end- diastolic diameter (LVIDd) and stroke volume (SV)(P<0.01) than the untrained subjects. As the supine cycling loads were gradually increased, the untrained subjects exhibited a progressive but significant decrease of LVIDd (P<0.01), while the athletes showed a progressive and significant enlargement of LVIDd (P<0.05) up till the workload was increased to 250 watts. when there was a slight decrease of LVIDd. The left ventricular end-systolic diameter (LVIDs) showed a gradual and significant decrease in both endurance athletes and untrained subjects. but the percentage of decrease in LVIDs is greater in the latter than in the former. SV increased in both groups at low workloads (100 and 150 watts), but it showed a rapid decrease in untrained subjects while continuing to increase in athletes at high workloads. Cardiac output (CO) showed parallel increase in both groups at low workloads, but the increment was much higher in athletes than in untrained subjects at high workloads, which revealed that the athletes had better cardiac reserves. Contractility measures, i,e., the ejection fraction (EF), the mean velocity of circumferential shortening (mVcf) and the percent left ventricular minor dimension shortening (%△D) increased in a similar manner in both groups. There was no significant difference in EF, mVcf and %△D between the two groups both at rest and during dynamic exercise. Conclusion: M-mode echocardiography is a very useful method for evaluating left ventricular perlormanee during dynamic exercise.