University Hospitals Leuven, Leuven, Belgium.
Eur J Prev Cardiol. 2013 Aug;20(4):597-604. doi: 10.1177/2047487312444372. Epub 2012 Mar 28.
This study aimed at evaluating (1) right ventricular (RV) mean power during exercise, (2) the contribution of flow and pressure to RV mean power, and (3) the impact of pulmonary artery pressure on RV function during exercise.
Fifty patients with atrial septal defect (ASD) type secundum (20 open, 30 closed) were enrolled. All underwent standard echocardiography, a bicycle stress echocardiography, and symptom-limited cardiopulmonary exercise testing. RV mean power was calculated as the product of RV cardiac output and mean pulmonary artery pressure (mPAP). RV function was assessed using RV fractional area change (FAC) at rest and at peak exercise.
RV mean power was linearly related with oxygen uptake (VO₂) in patients with open (R (2)= 0.88; p < 0.0001) and closed ASD (R(2)= 0.90; p < 0.0001). The increase in RV mean power was steeper in open than in closed ASD patients (p < 0.0001). The change in RV cardiac output (7.1 ± 3.4 vs. 5.7 ± 2.4 l/min; p = 0.132) was not statistically different, but the change in mPAP (21.7 ± 9.6 vs. 12.8 ± 4.6 mmHg; p < 0.0001) and RV mean power (0.97 ± 0.56 vs. 0.53 ± 0.22 W; p = 0.009) were higher in patients with an open ASD. The change in RV FAC from rest to peak exercise was related to peak mPAP in open (R = -0.589; p = 0.010) and closed (R = -0.450; p = 0.021) ASD patients.
RV mean power during exercise is higher in patients with an open than in patients with a closed ASD. The workload of the RV in patients with an open ASD is higher at rest due to a left-to-right shunt, at peak exercise due to an additional increase in mPAP. A higher increase in afterload may affect RV function during exercise.
本研究旨在评估：（1）运动时右心室（RV）平均功率；（2）流量和压力对 RV 平均功率的贡献；（3）肺动脉压对运动时 RV 功能的影响。
纳入 50 例房间隔缺损（ASD）Ⅱ型患者（20 例开放，30 例闭合）。所有患者均接受标准超声心动图、踏车运动超声心动图和症状限制心肺运动测试。RV 平均功率计算为 RV 心输出量与平均肺动脉压（mPAP）的乘积。RV 功能采用静息和峰值运动时 RV 分数面积变化（FAC）评估。
RV 平均功率与开放 ASD（R(2)=0.88；p<0.0001）和闭合 ASD（R(2)=0.90；p<0.0001）患者的摄氧量（VO₂）呈线性相关。与闭合 ASD 患者相比，开放 ASD 患者的 RV 平均功率增加更明显（p<0.0001）。RV 心输出量的变化（7.1±3.4 比 5.7±2.4 l/min；p=0.132）无统计学差异，但 mPAP（21.7±9.6 比 12.8±4.6 mmHg；p<0.0001）和 RV 平均功率（0.97±0.56 比 0.53±0.22 W；p=0.009）的变化更高。从静息到峰值运动的 RV FAC 变化与开放 ASD 患者的峰值 mPAP 相关（R=-0.589；p=0.010）和闭合 ASD 患者（R=-0.450；p=0.021）。
与闭合 ASD 患者相比，开放 ASD 患者运动时 RV 平均功率更高。由于左向右分流，开放 ASD 患者在静息时 RV 负荷更高，在峰值运动时由于 mPAP 额外增加，RV 负荷更高。后负荷的增加可能会影响运动时的 RV 功能。
