Nunan David, Sandercock Gavin R H, George Robert S, Jakovljevic Djordje G, Donovan Gay, Bougard Robert, Yacoub Magdi H, Brodie David A, Birks Emma J
Department of Primary Care Health Sciences, University of Oxford, Oxford, UK.
Int J Cardiol. 2013 Oct 9;168(4):4145-9. doi: 10.1016/j.ijcard.2013.07.075. Epub 2013 Jul 26.
The objective of the study is to determine cardiac autonomic control in patients undergoing assessment for and/or LVAD therapy.
Heart rate variability (HRV) was measured in 17 explanted LVAD, 17 implanted LVAD and 23 NYHA III-IV classified chronic heart failure (CHF) patients and ten healthy matched controls under three conditions: supine free breathing, standing and supine controlled breathing. Five measures of HRV were assessed: mean R-R interval (mR-R), high frequency (HF) and low frequency (LF) spectral power, LF in normalised units (LFnu), and LF to HF (LF:HF) ratio.
Repeat measures ANOVA showed significant (p < 0.05) differences in HRV between all three conditions within groups. Lower values were observed in CHF for LF(in log natural units) compared with explanted patients (-1.4 [95% CI -2.6 to -0.7], p = 0.04) and controls (-2.1 [-3.5 to -0.7], p = 0.001) and for LF:HF compared with implanted patients under paced breathing conditions (z = -2.7, p = 0.007) and controls in standing (z = -2.9, p = 0.004) and paced breathing conditions (z = -2.3, p = 0.02). However, no significant differences were seen between explanted, implanted and control groups under any condition.
Patients implanted with an LVAD and explanted from a LVAD following myocardial recovery demonstrate a more normal dynamic response to autonomic stimuli and have a lower HRV risk profile compared to CHF patients.
本研究的目的是确定接受左心室辅助装置（LVAD）评估和/或治疗的患者的心脏自主神经控制情况。
在17例已植入LVAD后又移除装置的患者、17例植入LVAD的患者、23例纽约心脏协会（NYHA）III-IV级慢性心力衰竭（CHF）患者以及10名健康对照者中，于三种状态下测量心率变异性（HRV）：仰卧位自由呼吸、站立位和仰卧位控制呼吸。评估了HRV的五项指标：平均RR间期（mR-R）、高频（HF）和低频（LF）频谱功率、标准化单位下的LF（LFnu）以及LF与HF的比值（LF:HF）。
重复测量方差分析显示，各组内所有三种状态下的HRV存在显著差异（p < 0.05）。与已移除装置的患者相比，CHF患者的LF（以自然对数单位计）较低（-1.4 [95%可信区间-2.6至-0.7]，p = 0.04），与对照组相比也较低（-2.1 [-3.5至-0.7]，p = 0.001）；在起搏呼吸状态下，与植入LVAD患者相比，CHF患者的LF:HF较低（z = -2.7，p = 0.007），在站立位时与对照组相比（z = -2.9，p = 0.004）以及在起搏呼吸状态下（z = -2.3，p = 0.02）也较低。然而，在任何状态下，已移除装置的患者、植入LVAD的患者和对照组之间均未观察到显著差异。
与CHF患者相比，植入LVAD以及心肌恢复后移除LVAD的患者对自主神经刺激表现出更正常的动态反应，且HRV风险较低。
