Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA.
Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, Dallas, TX, USA.
Physiol Rep. 2020 Nov;8(22):e14634. doi: 10.14814/phy2.14634.
Obesity plays an important role in functional impairment in HFpEF. The mechanisms underlying decreased functional capacity in obese HFpEF are not clear. We assessed the cardiac and peripheral determinants of exercise performance in HFpEF patients with class 2 obesity in the upright position, representative of posture when performing functional activities.
Thirty-two HFpEF patients were divided into two groups by presence of class 2 obesity (C2, BMI ≥ 35 kg/m , n = 14) and non-C2 (BMI < 35 kg/m , n = 18). Participants performed a bout of submaximal exercise followed by incremental stages of treadmill exercise to determine peak aerobic power (peak VO ). Peak VO and Ve/VCO were measured using Douglas bags while cardiac output (Qc) and stroke volume (SV) were measured by acetylene rebreathing. The C2 group were younger than the non-C2 group (67 ± 6 versus 73 ± 6 years; p = .009). Comorbid condition burden was similar between groups. Peak VO indexed to body mass was not significantly different between groups. Absolute peak VO was higher in the C2 group secondary to a larger peak Qc (14.3 versus 11.0 L/min; p = .012). SV reserve was also higher in the C2 group (72 versus 49%; p = .038).
HFpEF patients with severe obesity had similar cardiorespiratory fitness compared to patients with lower BMI with similar comorbidity burden. Absolute VO was actually higher in the severely obese driven by larger Qc and SV reserve arguing against significant effects from obesity per se on aerobic performance. The presence of a larger "cardiac engine" may offer potential for fat-loss strategies to improve impairments in functional capacity in obese patients with HFpEF.
肥胖在 HFpEF 患者的功能障碍中起着重要作用。肥胖 HFpEF 患者运动能力下降的机制尚不清楚。我们评估了直立位（进行日常功能性活动时的体位）下 2 类肥胖 HFpEF 患者的心脏和外周决定因素，以评估其运动表现。
32 名 HFpEF 患者根据是否存在 2 类肥胖（C2，BMI≥35kg/m²，n=14）和非 C2（BMI<35kg/m²，n=18）分为两组。参与者进行亚最大强度运动，然后进行跑步机运动递增阶段，以确定峰值有氧能力（peak VO₂）。使用 Douglas 袋测量 peak VO₂和 Ve/VCO，通过乙炔再呼吸测量心输出量（Qc）和每搏输出量（SV）。C2 组比非 C2 组年轻（67±6 岁比 73±6 岁；p=0.009）。两组间合并症负担相似。峰值 VO₂与体重的比值在两组间无显著差异。由于峰值 Qc 更大（14.3 比 11.0 L/min；p=0.012），C2 组的绝对峰值 VO₂更高。C2 组的 SV 储备也更高（72 比 49%；p=0.038）。
与 BMI 较低且合并症负担相似的患者相比，严重肥胖的 HFpEF 患者的心肺适应能力相似。由于更大的 Qc 和 SV 储备，绝对 VO₂在肥胖患者中更高，这表明肥胖本身对有氧能力的影响不大。更大的“心脏引擎”的存在可能为肥胖 HFpEF 患者的减肥策略提供改善其功能能力的潜力。
