Harrington F, Murray A, Ford G A
Department of Medicine (Geriatrics), University of Newcastle upon Tyne, UK.
J Hypertens. 2000 Nov;18(11):1629-33. doi: 10.1097/00004872-200018110-00014.
Ageing and hypertension are associated with reduced baroreflex sensitivity (BRS) in young and middle-aged populations. The effects of blood pressure level on BRS in the older population are unclear. We examined the association between blood pressure and BRS in older persons with blood pressure below 180 mmHg.
BRS, high (alphaHF 0.15-0.4 Hz) and low (alphaLF 0.04-0.15 Hz) frequency alpha-index, was determined in 75 normotensive subjects (aged 75 +/- 4 years, 41% female, 131 +/- 10/74 +/- 7 mmHg) and 64 untreated hypertensive subjects (aged 76 +/- 5 years, 48% female, 165 +/- 7/ 88 +/- 7 mmHg) by spectral analysis of 20 min continuous blood pressure and heart rate recordings using finger plethysmography. Subjects were recruited from 10 general practices and were taking no cardiovascular medications.
High but not low frequency alpha-index was significantly blunted in hypertensive subjects (alphaHF 5.1 +/- 3.1 versus 8.4 +/- 7.4 ms/mmHg, P< 0.001 and alphaLF 4.7 +/- 3.0 versus 5.8 +/- 3.9 ms/mmHg, P= 0.07). Multivariate analysis of the relationship between age and blood pressure demonstrated systolic and to a lesser extent diastolic blood pressure were significant predictors of variance in BRS for alphaHF [systolic blood pressure (SBP) P< 0.0001, diastolic blood pressure (DBP) P< 0.05, r2 = 0.1] and alphaLF (SBP P=0.01, DBP P<0.05, r2 = 0.04). Age was not a significant predictor for either measure, in the 20 year range studied.
In an older population blood pressure is associated with reduced BRS, particularly for the high frequency component. Such a change may place older subjects with hypertension at increased risk of orthostatic hypotension, vasovagal syncope and sudden cardiac death.
在年轻和中年人群中，衰老和高血压与压力反射敏感性（BRS）降低有关。血压水平对老年人群BRS的影响尚不清楚。我们研究了血压低于180 mmHg的老年人中血压与BRS之间的关联。
通过使用手指体积描记法对20分钟连续血压和心率记录进行频谱分析，测定了75名血压正常的受试者（年龄75±4岁，女性占41%，收缩压/舒张压为131±10/74±7 mmHg）和64名未经治疗的高血压受试者（年龄76±5岁，女性占48%，收缩压/舒张压为165±7/88±7 mmHg）的BRS、高频（αHF 0.15 - 0.4 Hz）和低频（αLF 0.04 - 0.15 Hz）α指数。受试者从10家普通诊所招募，未服用心血管药物。
高血压受试者的高频而非低频α指数显著降低（αHF：5.1±3.1对8.4±7.4 ms/mmHg，P<0.001；αLF：4.7±3.0对5.8±3.9 ms/mmHg，P = 0.07）。年龄与血压关系的多变量分析表明，收缩压以及在较小程度上舒张压是αHF [收缩压（SBP）P<0.0001，舒张压（DBP）P<0.05，r2 = 0.1]和αLF（SBP P = 0.01，DBP P<0.05，r2 = 0.04）BRS方差的显著预测因素。在所研究的20年范围内，年龄对这两种测量指标均不是显著预测因素。
在老年人群中，血压与BRS降低有关，特别是高频成分。这种变化可能使老年高血压患者发生体位性低血压、血管迷走性晕厥和心源性猝死的风险增加。
