Simultaneous changes of left ventricular and left atrial size and function in normal subjects during exercise.
We performed dual M-mode exercise echocardiography, which records left ventricular (LV) and left atrial (LA) echocardiograms simultaneously, in 10 normal subjects to investigate mechanisms of cardiac adaptation to dynamic exercise. The LV end-diastolic dimension (EDD) increased significantly as exercise increased from mild to moderate (3-5%, p less than 0.05 and 0.001). At peak exercise the EDD was slightly increased, but it returned to the baseline during recovery. The LV end-systolic dimension (ESD) showed a progressive decrease with the severity of exercise (5-13%, p less than 0.05 and 0.001). It decreased further immediately after exercise (17-20%) and then returned to the resting value. The LV stroke dimension and fractional shortening increased as exercise changed from mild to moderate and reached a plateau at peak exercise. During recovery, they showed a transient increase and then decreased. By contrast, the LA dimensions, both maximum and minimum, increased significantly as exercise changed from mild to moderate (15-16% and 16-19%, p less than 0.01 and 0.001, respectively), but they were lower at peak exercise (12 and 14%). They returned rapidly to the resting values immediately after exercise. Thus, during exercise, LV function is augmented by the Frank-Starling mechanism in combination with increased contractility, while the LA is enlarged to receive the increased venous return accompanying dynamic exercise. These exercise-induced changes in LV performance return gradually to the resting state, but LA size recovers rapidly after the cessation of exercise.
D000293:Adolescent; D016275:Atrial Function; D001794:Blood Pressure; D002306:Cardiac Volume; D004452:Echocardiography; D005080:Exercise Test; D006321:Heart / Q000033:anatomy & histology / Q000502:physiology*; D006331:Heart Diseases / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion; D013318:Stroke Volume; D016276:Ventricular Function