Imbriaco M, Cuocolo A, Pace L, Nappi A, Nicolai E, Cardei S, Morisco C, Romano M, Salvatore M
Department of Nuclear Medicine, University Federico II, Napoli, Italy.
J Nucl Med. 1995 Apr;36(4):564-8.
Ambulatory monitoring (VEST) of left ventricular (LV) function is a useful and accurate method to measure cardiac function during exercise and rest. The aim of this study was to evaluate LV response to exercise in normal sedentary subjects.
Ten normal sedentary subjects underwent continuous ambulatory monitoring of LV function by VEST during upright bicycle exercise associated with combined analysis of pulmonary gas exchange. All parameters of LV function were measured in control conditions at rest, at the anaerobic threshold (point of nonlinear increase in ventilation relative to oxygen uptake) and at peak oxygen uptake (peak VO2).
Heart rate and cardiac output significantly increased from control conditions to anaerobic threshold (p < 0.001) and from anaerobic threshold to peak VO2 (p < 0.001). Ejection fraction, end diastolic volume and stroke volume significantly increased from control conditions to anaerobic threshold (p < 0.001), showing no significant change from anaerobic threshold to peak VO2. Finally, end-systolic volume significantly decreased from control conditions to anaerobic threshold (p < 0.001), showing no significant change from anaerobic threshold to peak VO2.
VEST is particularly useful in the evaluation of cardiac response to exercise in normal sedentary subjects, providing a better understanding of the spectrum of the normal LVEF response to exercise. Our data demonstrate that ejection fraction response to exercise is variable after anaerobic threshold, and a uniform increase is not necessarily expected in normal sedentary subjects.
动态监测（背心式）左心室（LV）功能是一种在运动和休息期间测量心脏功能的有用且准确的方法。本研究的目的是评估正常久坐不动受试者左心室对运动的反应。
10名正常久坐不动的受试者在进行直立自行车运动期间通过背心式动态监测左心室功能，并结合肺气体交换分析。在静息对照条件下、无氧阈值（通气相对于摄氧量的非线性增加点）和峰值摄氧量（峰值VO2）时测量左心室功能的所有参数。
心率和心输出量从对照条件到无氧阈值显著增加（p < 0.001），从无氧阈值到峰值VO2也显著增加（p < 0.001）。射血分数、舒张末期容积和每搏输出量从对照条件到无氧阈值显著增加（p < 0.001），从无氧阈值到峰值VO2无显著变化。最后，收缩末期容积从对照条件到无氧阈值显著降低（p < 0.001），从无氧阈值到峰值VO2无显著变化。
背心式动态监测在评估正常久坐不动受试者对运动的心脏反应方面特别有用，有助于更好地理解正常左心室射血分数（LVEF）对运动反应的范围。我们的数据表明，无氧阈值后运动时射血分数的反应是可变的，正常久坐不动的受试者不一定会有均匀增加。
