Absence of sympathetic overactivity in Afro-Caribbean hypertensive subjects studied by heart rate variability
Absence of sympathetic overactivity in Afro-Caribbean hypertensive subjects studied by heart rate variability
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DOI：
10.1038/sj.jhh.1001009
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发表时间：
2000-05-01
影响因子：
2.7
通讯作者：
Thom, SAM
中科院分区：
文献类型：
--
作者：
Guzzetti, S;Mayet, J;Thom, SAM
与白人高血压患者相比，黑人高血压患者左心室肥厚的患病率更高，死亡率也更高。交感神经活动的差异可能有助于解释高血压的种族差异。然而，先前的实验室研究并没有显示黑人受试者直接通向心脏的交感神经活动有任何增加。本研究的目的是研究黑人和白人高血压患者心脏交感神经-迷走神经平衡，分析整个24小时内的心率变异性。我们分析了52例从未接受过降压治疗的原发性高血压患者的动态心电图记录，其中26例为黑人，26例为白人。在时域和频域分析中考虑连续的300拍序列，其中150拍重叠（约600拍/天）。以归一化单位表示的低频频谱分量（0.04-0.15 Hz）功率的平均24小时值（即交感调节的标志）在黑人患者组中显著低于白人（分别为40.0+/-2.1 vs 53.6+/-3.6 nu， P< 0.01）。交感神经迷走神经平衡指标LF/HF比值（分别为4.11 +/- 0.58 vs 5.98 +/- 0.79， P< 0.05）也有类似的结果。在多元线性回归分析中，考虑舒张压、左室质量指数、种族和年龄作为自变量，只有种族（P < 0.002）和年龄（P < 0.01）可以独立预测归一化低频功率或LF/HF比值作为因变量。本研究结果表明，在整个24小时内，与白人高血压患者相比，黑人高血压患者的心脏交感神经调节有一定程度的钝化。
Black hypertensives present a greater prevalence of left ventricular hypertrophy and an increased mortality compared to white hypertensives. Differences in sympathetic activity might contribute to explain these racial differences in hypertension. Nevertheless, previous laboratory studies did not show any increase of sympathetic activity direct to the heart in black subjects. The aim of the present study was to investigate the cardiac sympatho-vagal balance in black and white hypertensives analysing heart rate variability, during the entire 24 h. We analysed Holter recordings of 52 essential hypertensive patients, who had never received antihypertensive treatment, 26 of whom were black and 26 were white. Consecutive series of 300 beats, with 150 beats overlapped (approximately 600 series/day), were considered for the analysis in time and frequency domain. The mean 24-h value of the power of the low frequency spectral component (0.04-0.15 Hz), expressed in normalised units, ie a marker of sympathetic modulation, was significantly lower in the group of black patients compared to whites (respectively 40.0+/-2.1 vs 53.6+/-3.6 nu, P< 0.01). Similar results were observed for the LF/HF ratio, an index of the sympatho-vagal balance (respectively 4.11 +/- 0.58 vs 5.98 +/- 0.79; P< 0.05). In a multiple linear regression analysis, considering diastolic blood pressure, left ventricular mass index, race and age as independent variables, only race (P < 0.002) and age (P < 0.01) could independently predict the normalised low frequency power or the LF/HF ratio, as dependent variables. The results of this study suggest some blunting of the cardiac sympathetic neural modulation in black hypertensives compared to white hypertensives, during the entire 24 h.