Médigue C, Girard A, Laude D, Monti A, Wargon M, Elghozi J L
Institut National de Recherche en Informatique et en Automatique (INRIA), Rocquencourt, France.
Pflugers Arch. 2001 Feb;441(5):650-5. doi: 10.1007/s004240000486.
Respiratory sinus arrhythmia (RSA) estimation is commonly used as a non-invasive index of cardiac vagal tone. To test this relationship, vagal tone was augmented or blocked using atropine. The study was carried out using 14 healthy volunteers, following beta-adrenoceptor blockade (10 mg bisoprolol per os) and during controlled respiration (0.25 Hz) in order to limit the confounding effects of cardiac sympathetic tone and respiration pattern changes. Atropine was slowly infused intravenously over a 30-min period up to a vagolytic cumulative dose of 0.04 mg/kg. The instant vagal tone was compared to the instant RSA value obtained from a time-/frequency-domain analysis of pulse interval (PI). RSA and PI varied in the same direction with an initial increase corresponding to the early vagomimetic effect of atropine followed by a decrease during the vagolytic phase. The comparative percentage fluctuations of RSA and PI over this large vagal tone range indicate that RSA is more sensitive (about twofold) than PI in reflecting fluctuations around the set point. This dissociated behaviour of PI and heart rate variability could be important to our understanding of the circulatory changes that result from fluctuations in vagal inputs to the sinus node.
呼吸性窦性心律不齐（RSA）评估通常被用作心脏迷走神经张力的无创指标。为了验证这种关系，使用阿托品增强或阻断迷走神经张力。该研究对14名健康志愿者进行，在β-肾上腺素能受体阻断（口服10 mg比索洛尔）后以及控制呼吸（0.25 Hz）期间进行，以限制心脏交感神经张力和呼吸模式变化的混杂效应。阿托品在30分钟内缓慢静脉输注，直至达到0.04 mg/kg的迷走神经阻断累积剂量。将即时迷走神经张力与通过脉搏间期（PI）的时域/频域分析获得的即时RSA值进行比较。RSA和PI在相同方向上变化，最初的增加对应于阿托品的早期拟迷走神经效应，随后在迷走神经阻断阶段下降。在这个较大的迷走神经张力范围内，RSA和PI的比较百分比波动表明，RSA在反映设定点周围的波动方面比PI更敏感（约两倍）。PI和心率变异性的这种分离行为对于我们理解由窦房结迷走神经输入波动引起的循环变化可能很重要。
