Percy R F, Conetta D A, Miller A B
Division of Cardiology, University Hospital of Jacksonville, Florida 32209.
Am J Cardiol. 1990 May 1;65(16):1140-4. doi: 10.1016/0002-9149(90)90328-x.
Fourteen normal subjects and 10 marathon runners were studied using postexercise echocardiography to assess left ventricular (LV) wall thickness, afterload and systolic performance. Cuff systolic blood pressures and M-mode echocardiographic recordings were obtained in the supine position before and within 2 minutes of termination of maximal treadmill exercise. Both groups had increased LV dimensional shortening (% fractional shortening) and stroke volume after exercise, although runners had larger increases compared to untrained normal subjects (p less than 0.05). Preload, as estimated by LV end-diastolic dimension, was greater in runners compared to normal subjects at rest (52 vs 48 mm, p less than 0.05). However, preload did not change after exercise in either group. Afterload, estimated by LV end-systolic wall stress, decreased after exercise in both groups; however, runners had lower afterload at rest and immediately after exercise compared to normal subjects (p less than 0.05). The runners' greater LV end-systolic wall thickness appears to account for their lower afterload. Data indicate that marathon runners have lower afterload at rest and greater decrease in afterload after maximal exercise, compared to untrained normal subjects.
对14名正常受试者和10名马拉松运动员进行了研究，采用运动后超声心动图评估左心室（LV）壁厚度、后负荷和收缩功能。在最大强度跑步机运动终止前及终止后2分钟内，于仰卧位测量袖带收缩压并进行M型超声心动图记录。两组运动后左心室尺寸缩短（%缩短分数）和每搏输出量均增加，不过与未训练的正常受试者相比，跑步运动员的增加幅度更大（p<0.05）。静息时，以左心室舒张末期内径估算的前负荷，跑步运动员高于正常受试者（52对48mm，p<0.05）。然而，两组运动后前负荷均未改变。以左心室收缩末期壁应力估算的后负荷，两组运动后均降低；不过，与正常受试者相比，跑步运动员静息时及运动后即刻的后负荷更低（p<0.05）。跑步运动员较大的左心室收缩末期壁厚度似乎是其较低后负荷的原因。数据表明，与未训练的正常受试者相比，马拉松运动员静息时后负荷更低，最大运动后后负荷降低幅度更大。
