Davies L Ceri, Colhoun Helen, Coats Andrew J S, Piepoli Massimo, Francis Darrel P
National Heart and Lung Institute, Imperial College of Science, Technology, and Medicine, London, United Kingdom.
Am Heart J. 2002 Mar;143(3):441-7. doi: 10.1067/mhj.2002.121263.
Baroreflex sensitivity (BRS) and heart rate variability (HRV) are attenuated in cardiovascular disease and can give important prognostic information. Conventional measures of BRS require expensive or invasive equipment for the beat-to-beat measure of blood pressure (BP). We examined the possibility of developing a simple protocol that would provide a relatively standardized BP stimulus, which might obviate the need to measure BP beat-by-beat.
Fifty-five patients with chronic heart failure (mean age 59 [SD 11] years) and 20 healthy control subjects (mean age 53 [SD 14] years, P not significant) underwent 5-minute recordings of BP (by photoplethysmograph) and R-R interval during 0.1-Hz controlled breathing. The size of the oscillations in BP was the same in the 2 groups (3.6 mm Hg vs 4.1 mm Hg, P =.5). There was, however, a significant difference in the amplitude of the R-R interval oscillations (77 ms vs 31 ms, P <.0001). The amplitude of the R-R interval oscillations correlated strongly with BRS (r = 0.81, P <.0001 with controlled breathing BRS, and r = 0.51, P <.0001 with alpha index). There was no correlation with the size of BP oscillations (r = -0.13, P not significant with controlled breathing BRS, and r = -0.15, P not significant with alpha index). In a separate study, a group of 22 young patients (mean age 36 years) with type I diabetes mellitus and 28 healthy control subjects (mean age 39 years) underwent measurement of resting HRV and amplitude of R-R interval oscillations during 0.1-Hz breathing. There was no significant difference in triangular index or low-frequency R-R interval power between the 2 groups. There was, however, a significant difference in the amplitude of R-R interval oscillations during controlled breathing between patients with diabetes and healthy control subjects. Total and high-frequency RR interval variability was also significantly different between the 2 groups.
During 0.1-Hz breathing, the marked difference in BRS between patients with CHF and age-matched control subjects is the result of smaller R-R interval oscillations. In young patients with diabetes, these R-R interval oscillations are significantly smaller than age-matched control subjects, even when some measures of spontaneous HRV are not different between groups. Breathing at 0.1 Hz provides a standard BP stimulus and concentrates spectral power of heart rate at one frequency, enabling simple evaluation of BRS even when BP measurement is not available.
压力反射敏感性（BRS）和心率变异性（HRV）在心血管疾病中会减弱，并且能提供重要的预后信息。传统的BRS测量方法需要昂贵或有创的设备来逐搏测量血压（BP）。我们研究了开发一种简单方案的可能性，该方案可提供相对标准化的血压刺激，这可能无需逐搏测量血压。
55例慢性心力衰竭患者（平均年龄59[标准差11]岁）和20名健康对照者（平均年龄53[标准差14]岁，P无显著性差异）在0.1Hz控制呼吸期间进行了5分钟的血压（通过光电容积描记法）和R-R间期记录。两组血压振荡的大小相同（3.6mmHg对4.1mmHg，P = 0.5）。然而，R-R间期振荡的幅度存在显著差异（77ms对31ms，P < 0.0001）。R-R间期振荡的幅度与BRS密切相关（r = 0.81，与控制呼吸BRS的P < 0.0001，与α指数的r = 0.51，P < 0.0001）。与血压振荡的大小无相关性（r = -0.13，与控制呼吸BRS的P无显著性差异，与α指数的r = -0.15，P无显著性差异）。在另一项研究中，一组22例I型糖尿病年轻患者（平均年龄36岁）和28名健康对照者（平均年龄39岁）在0.1Hz呼吸期间进行了静息HRV和R-R间期振荡幅度的测量。两组之间的三角指数或低频R-R间期功率无显著差异。然而，糖尿病患者与健康对照者在控制呼吸期间R-R间期振荡的幅度存在显著差异。两组之间的总R-R间期变异性和高频R-R间期变异性也有显著差异。
在0.1Hz呼吸期间，慢性心力衰竭患者与年龄匹配的对照者之间BRS的显著差异是R-R间期振荡较小的结果。在年轻糖尿病患者中，即使两组之间一些自发HRV的测量值无差异，这些R-R间期振荡也显著小于年龄匹配的对照者。0.1Hz呼吸提供了标准的血压刺激，并将心率的频谱功率集中在一个频率上，即使在无法测量血压时也能简单地评估BRS。
