Ponikowski P, Chua T P, Amadi A A, Piepoli M, Harrington D, Volterrani M, Colombo R, Mazzuero G, Giordano A, Coats A J
Department of Cardiac Medicine, Imperial College, National Heart & Lung Institute, London, United Kingdom.
Am J Cardiol. 1996 Jun 15;77(15):1320-6. doi: 10.1016/s0002-9149(96)00199-3.
Although in advanced chronic congestive heart failure (CHF) very low frequency (< 0.04 Hz, VLF) oscillations are prominent, the clinical importance and the physiologic basis of these rhythms have not been elucidated. To investigate the physiologic determinants of the VLF rhythms in RR interval variability, we studied 36 patients with stable, moderate to severe CHF (33 men, age: 58 +/- 8 years, ejection fraction 25 +/- 10%, peak oxygen consumption 18.1 +/- 4.6 ml/kg/min) and 12 age- and sex-matched controls using autoregressive spectral analysis of RR interval, blood pressure, and respiratory signals during controlled conditions. We quantified low frequency (LF) (0.04 to 0.15 Hz), high frequency (HF) (0.15 to 0.40 Hz), VLF, and total power (0 to 0.5 Hz), and calculated the coherence between systolic blood pressure and RR interval variability within each band. Peripheral chemosensitivity was assessed by the ventilatory response to hypoxia using transient inhalation of pure nitrogen. The influence of transient inactivation of peripheral chemoreceptors on the VLF rhythm was investigated by exposing 6 patients to hyperoxic (60% oxygen) conditions for 20 minutes. Twenty-three patients (64%) with CHF, but no controls, had a discrete VLF rhythm (0.019 +/- 0.008 Hz) in RR variability. The presence of VLF rhythm was not related to any difference in clinical parameters (etiology, New York Heart Association class, ejection fraction, oxygen uptake) but rather to a different pattern in RR interval and blood pressure variability: lower LF power (2.8 +/- 1.6 ms2 natural logarithm [ln]) compared either to patients without VLF (4.0 +/- 1.3 ms2 ln) or to controls (5.9 +/- 0.7 ms2 ln), higher percentage of power within VLF band (86.3 +/- 8.3% vs 77.5 +/- 7.9% and 61.5 +/- 14.1%) and a markedly impaired coherence between RR interval and systolic blood pressure variability within the LF band (0.26 +/- 0.10 vs 0.42 +/- 0.18 and 0.63 +/- 0.15, in patients with vs without VLF peak and controls, respectively). Patients with VLF had significantly increased hypoxic chemosensitivity, and hyperoxic conditions were able to decrease VLF power and abolish the VLF rhythm in 5 of 6 patients with CHF. Discrete VLF oscillations in RR variability are common in patients with advanced CHF and appear to be related to severely impaired autonomic regulation and suppression of baroreceptor function, with enhancement of hypoxic chemosensitivity. We hypothesize that this rhythm represents an enhanced chemoreflex harmonic oscillation in CHF patients, which may have application for arrhythmogenesis.
尽管在晚期慢性充血性心力衰竭（CHF）中，极低频（<0.04Hz，VLF）振荡很突出，但这些节律的临床重要性和生理基础尚未阐明。为了研究RR间期变异性中VLF节律的生理决定因素，我们使用RR间期、血压和呼吸信号的自回归谱分析，在可控条件下研究了36例稳定的中重度CHF患者（33例男性，年龄：58±8岁，射血分数25±10%，峰值耗氧量18.1±4.6ml/kg/min）和12例年龄及性别匹配的对照者。我们对低频（LF）（0.04至0.15Hz）、高频（HF）（0.15至0.40Hz）、VLF和总功率（0至0.5Hz）进行了量化，并计算了每个频段内收缩压与RR间期变异性之间的相干性。通过短暂吸入纯氮对低氧的通气反应来评估外周化学敏感性。通过让6例患者暴露于高氧（60%氧气）环境20分钟，研究外周化学感受器短暂失活对VLF节律的影响。23例（64%）CHF患者而非对照者在RR变异性中有离散的VLF节律（0.019±0.008Hz）。VLF节律的存在与临床参数（病因、纽约心脏协会分级、射血分数、摄氧量）的任何差异均无关，而是与RR间期和血压变异性的不同模式有关：与无VLF的患者（4.0±1.3ms2自然对数[ln]）或对照者（5.9±0.7ms2ln）相比，LF功率较低（2.8±1.6ms2ln），VLF频段内功率百分比更高（86.3±8.3%对77.5±7.9%和61.5±14.1%），并且LF频段内RR间期与收缩压变异性之间的相干性明显受损（有VLF峰值的患者、无VLF峰值的患者和对照者分别为0.26±0.10、0.42±0.18和0.63±0.15）。有VLF的患者低氧化学敏感性显著增加，高氧环境能够降低6例CHF患者中5例的VLF功率并消除VLF节律。RR变异性中的离散VLF振荡在晚期CHF患者中很常见，似乎与严重受损的自主神经调节和压力感受器功能抑制有关，同时伴有低氧化学敏感性增强。我们推测这种节律代表CHF患者增强的化学反射谐波振荡，这可能与心律失常的发生有关。
