Pitzalis M V, Mastropasqua F, Massari F, Passantino A, Colombo R, Mannarini A, Forleo C, Rizzon P
Institute of Cardiology, University of Bari, Italy.
Cardiovasc Res. 1998 May;38(2):332-9. doi: 10.1016/s0008-6363(98)00029-7.
The aims of this study were to determine the relationships between oscillations in systolic blood pressure and heart period at different breathing frequencies and to investigate the role of sympathetic contribution to this relationship.
Fourteen healthy volunteers underwent three randomized periods of controlled breathing at 6, 10 and 16 breaths/min. ECG (RR), respiratory signal (RESP) and systolic blood pressure (SBP) were continuously recorded. The component of RR and SBP oscillations related to respiration (RRResp and SBPResp) was defined by means of uni- and bivariate spectral analysis. The squared coherence (K2) and phase between RR and RESP, and RR and SBP (RR-SBP) were also assessed. When the K2 of RR-SBP in the respiratory band was > 0.5, we considered the phase and calculated the closed-loop gain between the two signals. Seven subjects were also studied after chronic metoprolol treatment.
Although the mean values of RR and SBP did not differ between the three periods of breathing, the higher the respiratory rate, the smaller the RRResp and SBPResp. The phase was always negative (SBPResp changes preceded RRResp changes), thus suggesting a baroreflex link. The higher the respiratory rate, the lower the gain and phase. Pharmacological beta-adrenoceptor blockade increased the gain and shifted the phase, but the relationships found at baseline between the respiratory rate and both the gain and phase remained unchanged.
The effect of breath rate on the relationship between heart rate and systolic pressure variabilities is a frequency-dependent phenomenon that is also independent of the sympathetic drive.
本研究旨在确定不同呼吸频率下收缩压振荡与心动周期之间的关系，并探讨交感神经在这种关系中的作用。
14名健康志愿者在6次/分钟、10次/分钟和16次/分钟的呼吸频率下进行了三个随机的控制呼吸阶段。连续记录心电图（RR）、呼吸信号（RESP）和收缩压（SBP）。通过单变量和双变量频谱分析定义与呼吸相关的RR和SBP振荡成分（RRResp和SBPResp）。还评估了RR与RESP以及RR与SBP之间的平方相干性（K2）和相位（RR-SBP）。当呼吸频段中RR-SBP的K2>0.5时，我们考虑相位并计算两个信号之间的闭环增益。7名受试者在慢性美托洛尔治疗后也进行了研究。
尽管三个呼吸阶段的RR和SBP平均值没有差异，但呼吸频率越高，RRResp和SBPResp越小。相位始终为负（SBPResp变化先于RRResp变化），因此提示存在压力反射联系。呼吸频率越高，增益和相位越低。药理学上的β-肾上腺素能阻滞剂增加了增益并改变了相位，但基线时发现的呼吸频率与增益和相位之间的关系保持不变。
呼吸频率对心率与收缩压变异性之间关系的影响是一种频率依赖性现象，且与交感神经驱动无关。
