Division of Cardiology Department of Medicine Medical University of South Carolina Charleston SC.
Cardiology Division Department of Medicine Larner College of Medicine at the University of Vermont Burlington VT.
J Am Heart Assoc. 2020 Sep;9(17):e017215. doi: 10.1161/JAHA.120.017215. Epub 2020 Aug 28.
Background Increases in heart rate are thought to result in incomplete left ventricular (LV) relaxation and elevated filling pressures in patients with heart failure with preserved ejection fraction (HFpEF). Experimental studies in isolated human myocardium have suggested that incomplete relaxation is a result of cellular Ca overload caused by increased myocardial Na levels. We tested these heart rate paradigms in patients with HFpEF and referent controls without hypertension. Methods and Results In 22 fully sedated and instrumented patients (12 controls and 10 patients with HFpEF) in sinus rhythm with a preserved ejection fraction (≥50%) we assessed left-sided filling pressures and volumes in sinus rhythm and with atrial pacing (95 beats per minute and 125 beats per minute) before atrial fibrillation ablation. Coronary sinus blood samples and flow measurements were also obtained. Seven women and 15 men were studied (aged 59±10 years, ejection fraction 61%±4%). Patients with HFpEF had a history of hypertension, dyspnea on exertion, concentric LV remodeling and a dilated left atrium, whereas controls did not. Pacing at 125 beats per minute lowered the mean LV end-diastolic pressure in both groups (controls -4.3±4.1 mm Hg versus patients with HFpEF -8.5±6.0 mm Hg, =0.08). Pacing also reduced LV end-diastolic volumes. The volume loss was about twice as much in the HFpEF group (controls -15%±14% versus patients with HFpEF -32%±11%, =0.009). Coronary venous [Ca] increased after pacing at 125 beats per minute in patients with HFpEF but not in controls. [Na] did not change. Conclusions Higher resting heart rates are associated with lower filling pressures in patients with and without HFpEF. Incomplete relaxation and LV filling at high heart rates lead to a reduction in LV volumes that is more pronounced in patients with HFpEF and may be associated with myocardial Ca retention.
在射血分数保留的心力衰竭（HFpEF）患者中，心率增加被认为导致左心室（LV）不完全松弛和充盈压升高。在分离的人类心肌的实验研究中，已经表明不完全松弛是由心肌 Na 水平增加引起的细胞 Ca 过载引起的。我们在 HFpEF 患者和没有高血压的参考对照者中测试了这些心率模型。
在 22 名处于窦性心律且射血分数（≥50%）保留的充分镇静和仪器化患者（12 名对照者和 10 名 HFpEF 患者）中，我们在窦性心律和心房起搏（95 次/分钟和 125 次/分钟）下评估了左侧充盈压和容量在心房颤动消融之前。还获得了冠状窦血液样本和流量测量值。7 名女性和 15 名男性接受了研究（年龄 59±10 岁，射血分数 61%±4%）。HFpEF 患者有高血压、运动时呼吸困难、LV 向心性重构和左心房扩张的病史，而对照组则没有。以 125 次/分钟起搏降低了两组的平均 LV 舒张末期压力（对照组-4.3±4.1mmHg 与 HFpEF 患者-8.5±6.0mmHg，=0.08）。起搏也降低了 LV 舒张末期容量。HFpEF 组的容量损失约为对照组的两倍（对照组-15%±14%与 HFpEF 患者-32%±11%，=0.009）。HFpEF 患者在以 125 次/分钟起搏后，冠状静脉[Ca]增加，但对照组没有。[Na]没有变化。
在 HFpEF 患者和非 HFpEF 患者中，较高的静息心率与较低的充盈压相关。在高心率时，不完全松弛和 LV 充盈导致 LV 容积减少，在 HFpEF 患者中更为明显，可能与心肌 Ca 保留有关。
