Abstract：
The left atrium (LA) mediates cardiopulmonary interactions. During ventricular systole, the LA functions as a compliant reservoir that is coupled to the left ventricle (LV) and offloads volume from the pulmonary vasculature. We aimed to describe LA reservoir function using phasic relationships between pulmonary artery wedge pressure (PAWP) and LA volume events. We included healthy adults (7 M/6 F, 56 ± 8 yr) who were studied at rest and during semirecumbent cycle ergometry at a target of 100 beats/min heart rate. Right heart catheterization was performed to record the PAWP and two-dimensional (2-D) echocardiography was used to measure LA and LV volumes. We manually measured A-wave, x-trough, V-wave, and y-trough PAWP beat-by-beat, as well as minimal, maximal, and precontraction biplane LA volumes. Heart rate increased by 40 ± 7 beats/min with exercise; stroke volume and cardiac output also rose. Although all phasic PAWP measurements increased with exercise, the x-V pressure pulse during LA filling doubled from 4 ± 2 to 8 ± 4 mmHg (P = 0.001). LA minimal volume was unchanged but maximal volume increased from 39 ± 9 to 48 ± 9 mL (P < 0.001) with exercise, and so reservoir volume increased from 24 ± 5 to 32 ± 8 mL (P < 0.001). As such, calculated LA compliance decreased from 6.8 ± 3.4 to 4.8 ± 2.6 mL/mmHg (P = 0.029). The product of V-wave PAWP and LA maximal volume, a surrogate for LA wall stress, increased from 486 ± 193 to 953 ± 457 mmHg·mL (P < 0.001). In healthy older adults during submaximal exercise, the PAWP waveform shifts upward and its amplitude widens, LA filling increases, LA compliance decreases modestly, and LA wall stress may augment substantially.NEW & NOTEWORTHY We combined invasive estimates of left atrial pressure with noninvasive left atrial volume measurements made at rest and during exercise in healthy humans. Left atrial pressure and volume both increased with exercise, though the pressure increase was relatively greater, and calculated compliance decreased modestly while estimated peak wall stress nearly doubled. Our results demonstrate left atrial loading during exercise in healthy older adults and provide insight into how the left atrium mediates cardiopulmonary interactions.
摘要：
左心房(LA)介导心肺相互作用。在心室收缩期间，LA用作耦合到左心室(LV)并从肺脉管系统卸载体积的顺应性储存器。我们旨在使用肺动脉楔压（PAWP）和LA容量事件之间的相位关系来描述LA储集功能。我们包括健康的成年人(7米/6楼，56±8年），在休息和半卧位周期测功期间以100次/分钟的心率为目标进行研究。进行右心导管检查以记录PAWP，并使用二维（2-D）超声心动图测量LA和LV体积。我们手动测量了A波，x型槽,V波,和y槽PAWP逐拍，以及最小的，最大,和收缩前双平面LA体积。运动使心率增加40±7次/分钟；每搏量和心输出量也增加。尽管所有阶段性PAWP测量值都随着运动而增加，左心房充盈期间x-V压力脉冲从4±2增加到8±4mmHg(P=0.001)。LA最小体积不变，但最大体积从39±9mL增加到48±9mL（P<0.001）。因此，储液器体积从24±5毫升增加到32±8毫升(P<0.001)。因此，计算的LA依从性从6.8±3.4下降至4.8±2.6mL/mmHg(P=0.029).V波PAWP和LA最大体积的乘积，洛杉矶墙壁应力的替代品，从486±193上升到953±457mmHg·mL（P<0.001）。在健康的老年人中，在次最大运动期间，PAWP波形向上移动，振幅变宽，LA填充增加，洛杉矶的合规性略有下降，LA壁应力可能会大幅增加。NEW&NOTEWORTHY我们将左心房压力的侵入性估计与健康人在休息和运动期间进行的非侵入性左心房容积测量相结合。左心房压力和容量都随着运动而增加，尽管压力增加相对更大，计算出的顺应性略有下降，而估计的峰值壁应力几乎翻了一番。我们的结果证明了健康老年人在运动期间的左心房负荷，并提供了对左心房如何介导心肺相互作用的见解。
