Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, United States.
Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States.
J Appl Physiol (1985). 2024 Mar 1;136(3):525-534. doi: 10.1152/japplphysiol.00510.2023. Epub 2024 Jan 4.
Heart failure with preserved ejection fraction (HFpEF) is associated with autonomic dysregulation, which may be related to baroreflex dysfunction. Thus, we tested the hypothesis that cardiac and peripheral vascular responses to baroreflex activation via lower-body negative pressure (LBNP; -10, -20, -30, -40 mmHg) would be diminished in patients with HFpEF ( = 10, 71 ± 7 yr) compared with healthy controls (CON, = 9, 69 ± 5 yr). Changes in heart rate (HR), mean arterial pressure (MAP, Finapres), forearm blood flow (FBF, ultrasound Doppler), and thoracic impedance (Z) were determined. Mild levels of LBNP (-10 and -20 mmHg) were used to specifically assess the cardiopulmonary baroreflex, whereas responses across the greater levels of LBNP represented an integrated baroreflex response. LBNP significantly increased in HR in CON subjects at -30 and -40 mmHg (+3 ± 3 and +6 ± 5 beats/min, < 0.01), but was unchanged in patients with HFpEF across all LBNP levels. LBNP provoked progressive peripheral vasoconstriction, as quantified by changes in forearm vascular conductance (FVC), in both groups. However, a marked (40%-60%) attenuation in FVC responses was observed in patients with HFpEF (-6 ± 8, -15 ± 6, -16 ± 5, and -19 ± 7 mL/min/mmHg at -10, -20, -30, and -40 mmHg, respectively) compared with controls (-15 ± 10, -22 ± 6, -25 ± 10, and -28 ± 10 mL/min/mmHg, < 0.01). MAP was unchanged in both groups. Together, these data provide new evidence for impairments in cardiopulmonary baroreflex function and diminished cardiovascular responsiveness during hypovolemia in patients with HFpEF, which may be an important aspect of the disease-related changes in autonomic cardiovascular control in this patient group. Data from the current study demonstrate diminished cardiovascular responsiveness during hypovolemia induced by incremental lower-body negative pressure in patients with heart failure with preserved ejection fraction (HFpEF). These diminished responses imply impaired cardiopulmonary baroreflex function and altered autonomic cardiovascular regulation which may represent an important aspect of HFpEF pathophysiology.
射血分数保留的心力衰竭（HFpEF）与自主神经调节障碍有关，这可能与压力反射功能障碍有关。因此，我们假设通过下体负压（LBNP；-10、-20、-30、-40mmHg）激活压力反射时，HFpEF 患者（n=10，71±7 岁）的心脏和外周血管反应会减弱，与健康对照组（CON，n=9，69±5 岁）相比。测定心率（HR）、平均动脉压（MAP，Finapres）、前臂血流（FBF，超声多普勒）和胸阻抗（Z）的变化。使用轻度 LBNP（-10 和-20mmHg）专门评估心肺压力反射，而 LBNP 较大水平的反应代表综合压力反射反应。在 CON 受试者中，LBNP 在-30 和-40mmHg 时显著增加 HR（+3±3 和+6±5 次/分钟， < 0.01），但 HFpEF 患者在所有 LBNP 水平下均无变化。在两组中，通过前臂血管传导性（FVC）的变化来量化 LBNP 引起的外周血管逐渐收缩。然而，在 HFpEF 患者中，FVC 反应明显减弱（-10、-20、-30 和-40mmHg 时分别为-6±8、-15±6、-16±5 和-19±7mL/min/mmHg）与对照组相比（-15±10、-22±6、-25±10 和-28±10mL/min/mmHg， < 0.01）。MAP 在两组中均无变化。综上所述，这些数据为 HFpEF 患者低血容量时心肺压力反射功能受损和心血管反应性降低提供了新的证据，这可能是该患者组自主心血管控制疾病相关变化的重要方面。当前研究的数据表明，在射血分数保留的心力衰竭（HFpEF）患者中，通过逐渐增加下体负压引起的低血容量时，心血管反应性降低。这些反应减弱意味着心肺压力反射功能受损和自主心血管调节改变，这可能代表 HFpEF 病理生理学的一个重要方面。
