Low frequency spectral component of heart rate variability and myocardial beta-adrenoceptor density after acute myocardial infarction
Low frequency spectral component of heart rate variability and myocardial beta-adrenoceptor density after acute myocardial infarction
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DOI：
10.1007/s395-002-8392-8
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发表时间：
2002-01-01
影响因子：
9.5
通讯作者：
Camici, PG
中科院分区：
文献类型：
--
作者：
Guzzetti, S;Spyrou, N;Camici, PG
目的心率变异性（heartratevariability，HRV）的低频频谱成分（lowfrequencyspectralcomponent，LF; 0.04- 0.15Hz）被认为是生理状态下交感神经对窦房结活动调节的指标，但在非生理状态下二者的关系尚不明确。几种心血管疾病的特征在于LF频谱分量的24小时模式缺失或钝化。本研究的目的是调查慢性增加的神经交感神经传出驱动心脏，心肌β受体的下调方面量化，和24小时的功率的LF频谱成分在急性心肌梗死后的患者之间的关系。方法对24例无并发症的Q波心肌梗死患者在发病后1个月进行24小时的HRV分析。计算以下时域测量值和频谱分量：平均RR、SDNN、SDANN、RMSSD、SDNN指数、pNN 50以及极低频（VLF）、低频（LF）和高频（HF）频谱分量。使用C-11-CGP 12177通过正电子发射断层扫描（PET）在体内测量β-肾上腺素受体的密度。结果AMI后患者血浆肾上腺素和去甲肾上腺素水平正常（分别为1.48 ± 0.18和0.28 ± 0.03 IU/L），但心肌β受体密度降低（6.86 ± 0.24 pmol/g）。与对照组相比，患者的心率相似，但SDNN和SDANN值较低。两组患者的频谱成分的绝对功率和归一化功率相似，但患者通常的昼夜振荡减弱。此外，LF频谱成分功率的昼夜变化与心肌β-肾上腺素能受体密度呈正相关（r = 0.51; p < 0.001）。结论急性心肌梗死患者LF频谱昼夜振荡消失是持续性交感神经过度兴奋的重要标志。
Objective The low frequency spectral component (LF; 0.04-0.15 Hz) of heart rate variability (HRV) is considered to be an index of sympathetic modulation of sinus node activity under physiological conditions, although the relationship is less clearly defined in non-physiological conditions. Several cardiovascular diseases are characterized by an absent or blunted 24-h pattern of the LF spectral component. The aim of the present study was to investigate the relationship between chronically increased neural sympathetic efferent drive to the heart, quantified in terms of downregulation of myocardial beta-receptors, and the 24-h power of the LF spectral component in patients after acute myocardial infarction. Methods In 24 patients, HRV was analyzed for a 24-h period, one month after an uncomplicated Q wave myocardial infarction. The following time domain measures and spectral components were calculated: mean RR, SDNN, SDANN, RMSSD, SDNN index, pNN50, and very low frequency (VLF), low frequency (LF) and high frequency (HF) spectral components. The density of beta-adrenoceptors was measured in vivo by positron emission tomography (PET) with C-11-CGP12177. Results Post-AMI patients had normal plasma levels of adrenaline and noradrenaline (respectively 1.48 +/- 0.18 and 0.28 +/- 0.03 IU/L) but reduced myocardial beta-adrenoceptor density (6.86 +/- 0.24 pmol/g). Patients had similar heart rates but lower values of SDNN and SDANN compared with control subjects. The absolute and normalized power of the spectral components were similar in the two groups, but the usual day-night oscillation was blunted in patients. Moreover, the day-night change in the power of the LF spectral component was positively related (r = 0.51; p < 0.001) to the myocardial beta-adrenoceptor density. Conclusions The loss of the day-night oscillation of the LF spectral component appears to be a significant marker of sustained sympathetic over-activity in post-AMI patients.