Labatt Family Heart Center, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
Institute of Sport, Exercise and Health, University College London, London, United Kingdom.
Am J Physiol Heart Circ Physiol. 2024 Oct 1;327(4):H749-H764. doi: 10.1152/ajpheart.00096.2024. Epub 2024 Jul 26.
Despite exercise intolerance being predictive of outcomes in pulmonary arterial hypertension (PAH), its underlying cardiac mechanisms are not well described. The aim of the study was to explore the biventricular response to exercise and its associations with cardiorespiratory fitness in children with PAH. Participants underwent incremental cardiopulmonary exercise testing and simultaneous exercise echocardiography on a recumbent cycle ergometer. Linear mixed models were used to assess cardiac function variance and associations between cardiac and metabolic parameters during exercise. Eleven participants were included with a mean age of 13.4 ± 2.9 yr old. Right ventricle (RV) systolic pressure (RVsp) increased from a mean of 59 ± 25 mmHg at rest to 130 ± 40 mmHg at peak exercise ( < 0.001), whereas RV fractional area change (RV-FAC) and RV-free wall longitudinal strain (RVFW-S) worsened (35.2 vs. 27%, = 0.09 and -16.6 vs. -14.6%, = 0.1, respectively). At low- and moderate-intensity exercise, RVsp was positively associated with stroke volume and O pulse ( < 0.1). At high-intensity exercise, RV-FAC, RVFW-S, and left ventricular longitudinal strain were positively associated with oxygen uptake and O pulse ( < 0.1), whereas stroke volume decreased toward peak ( = 0.04). In children with PAH, the increase of pulmonary pressure alone does not limit peak exercise, but rather the concomitant reduced RV functional reserve, resulting in RV to pulmonary artery (RV-PA) uncoupling, worsening of interventricular interaction and LV dysfunction. A better mechanistic understanding of PAH exercise physiopathology can inform stress testing and cardiac rehabilitation in this population. In children with pulmonary arterial hypertension, there is a marked increase in pulmonary artery pressure during physical activity, but this is not the underlying mechanism that limits exercise. Instead, right ventricle-to-pulmonary artery uncoupling occurs at the transition from moderate to high-intensity exercise and correlates with lower peak oxygen uptake. This highlights the more complex underlying pathological responses and the need for multiparametric assessment of cardiac function reserve in these patients when feasible.
尽管运动不耐受可预测肺动脉高压（PAH）的结局，但它的心脏潜在机制尚未得到很好的描述。本研究旨在探讨 PAH 患儿运动时的双心室反应及其与心肺适应能力的关系。参与者在斜躺式自行车测力计上进行递增心肺运动测试和同步运动超声心动图检查。线性混合模型用于评估运动过程中心脏功能的变化，并评估心脏和代谢参数之间的相关性。纳入 11 名参与者，平均年龄为 13.4 ± 2.9 岁。右心室（RV）收缩压（RVsp）从休息时的平均 59 ± 25mmHg 增加到峰值运动时的 130 ± 40mmHg（<0.001），而 RV 分数面积变化（RV-FAC）和 RV 游离壁纵向应变（RVFW-S）恶化（35.2%比 27%，=0.09 和-16.6%比-14.6%，=0.1）。在低强度和中等强度运动时，RVsp 与每搏量和 O 脉搏呈正相关（<0.1）。在高强度运动时，RV-FAC、RVFW-S 和左心室纵向应变与摄氧量和 O 脉搏呈正相关（<0.1），而每搏量在达到峰值时减少（=0.04）。在 PAH 患儿中，单纯肺动脉压的升高并不限制峰值运动，而是 RV 功能储备的相应降低导致 RV 与肺动脉（RV-PA）解偶联，心室间相互作用恶化和左心室功能障碍。对 PAH 运动病理生理学的更深入的机制理解可以为该人群的应激测试和心脏康复提供信息。在患有肺动脉高压的儿童中，运动期间肺动脉压会明显升高，但这并不是限制运动的根本机制。相反，从中等到高强度运动的过渡时会发生 RV-PA 解偶联，与较低的峰值摄氧量相关。这突显了更复杂的潜在病理反应，以及在可行的情况下，这些患者需要对心脏功能储备进行多参数评估。
