Oliveira Mário Martins, da Silva Nogueira, Timóteo Ana Teresa, Feliciano Joana, Silva Sofia, Xavier Rita, Rocha Isabel, Silva-Carvalho Luís, Ferreira Rui
Serviço de Cardiologia, Hospital de Santa Marta, Lisboa, Portugal.
Rev Port Cardiol. 2009 Mar;28(3):243-57.
The autonomic nervous system (ANS) is known to be an important modulator in the pathogenesis of paroxysmal atrial fibrillation (PAF). Changes in ANS control of heart rate variability (HRV) occur during orthostatism to maintain cardiovascular homeostasis. Wavelet transform has emerged as a useful tool that provides time-frequency decomposition of the signal under investigation, enabling intermittent components of transient phenomena to be analyzed.
To study HRV during head-up tilt (HUT) with wavelet transform analysis in PAF patients and healthy individuals (normals).
Twenty-one patients with PAF (8 men; age 58 +/- 14 yrs) were examined and compared with 21 normals (7 men, age 48 +/- 12 yrs). After a supine resting period, all subjects underwent passive HUT (60 degrees) while in sinus rhythm. Continuous monitoring of ECG and blood pressure was carried out (Task Force Monitor, CNSystems). Acute changes in RR-intervals were assessed by wavelet analysis and low-frequency power (LF: 0.04-0.15 Hz), high-frequency power (HF: 0.15-0.60 Hz) and LF/HF (sympathovagal) were calculated for 1) the last 2 min of the supine period; 2) the 15 sec of tilting movement (TM); and 3) the 1st (TT1) and 2nd (TT2) min of HUT. Data are expressed as means +/- SEM.
Baseline and HUT RR-intervals were similar for the two groups. Supine basal blood pressure was also similar for the two groups, with a sustained increase in PAF patients, and a decrease followed by an increase and then recovery in normals. Basal LF, HF and LF/ HF values in PAF patients were 632 +/- 162 ms2, 534 +/- 231 ms2 and 1.95 +/- 0.39 respectively, and 1058 +/- 223 ms2, 789 +/- 244 ms2 and 2.4 +/- 0.36 respectively in normals (p = NS). During TM, LF, HF and LF/HF values for PAF patients were 747 +/- 277 ms2, 387 +/- 94 ms2 and 2.9 +/- 0.6 respectively, and 1316 +/- 315 ms2, 698 +/- 148 ms2 and 2.8 +/- 0.6 respectively in normals (p < 0.05 for LF and HF). During TF1, LF, HF and LF/ HF values for PAF patients were 1243 +/- 432 ms2, 302 +/- 88 ms2 and 7.7 +/- 2.4 respectively, and 1992 +/- 398 ms2, 333 +/- 76 ms2 and 7.8 +/- 0.98 respectively for normals (p < 0.05 for LF). During TF2, LF, HF and LF/HF values for PAF patients were 871 +/- 256 ms2, 242 +/- 51 ms2 and 4.7 +/- 0.9 respectively, and 1263 +/- 335 ms2, 317 +/- 108 ms2 and 8.6 +/- 0.68 respectively for normals (p < 0.05 for LF/HF). The dynamic profile of HRV showed that LF and HF values in PAF patients did not change significantly during TM or TT2, and LF/HF did not change during TM but increased in TT1 and TT2.
Patients with PAF present alterations in HRV during orthostatism, with decreased LF and HF power during TM, without significant variations during the first minutes of HUT. These findings suggest that wavelet transform analysis may provide new insights when assessing autonomic heart regulation and highlight the presence of ANS disturbances in PAF.
自主神经系统（ANS）是阵发性心房颤动（PAF）发病机制中的重要调节因子。在直立位时，ANS对心率变异性（HRV）的控制会发生变化，以维持心血管稳态。小波变换已成为一种有用的工具，可对研究中的信号进行时频分解，从而能够分析瞬态现象的间歇性成分。
采用小波变换分析研究PAF患者和健康个体（正常人）在头高位倾斜（HUT）期间的HRV。
对21例PAF患者（8例男性；年龄58±14岁）进行检查，并与21例正常人（7例男性，年龄48±12岁）进行比较。在仰卧休息一段时间后，所有受试者在窦性心律下接受被动HUT（60度）。进行心电图和血压的连续监测（Task Force Monitor，CNSystems）。通过小波分析评估RR间期的急性变化，并计算仰卧期最后2分钟、倾斜运动（TM）的15秒以及HUT的第1分钟（TT1）和第2分钟（TT2）的低频功率（LF：0.04 - 0.15 Hz）、高频功率（HF：0.15 - 0.60 Hz）和LF/HF（交感迷走神经）。数据以均值±标准误表示。
两组的基线和HUT RR间期相似。两组仰卧位基础血压也相似，PAF患者血压持续升高，正常人血压先降低后升高然后恢复。PAF患者的基础LF、HF和LF/HF值分别为632±162 ms²、534±231 ms²和1.95±0.39，正常人分别为1058±223 ms²、789±244 ms²和2.4±0.36（p = 无显著性差异）。在TM期间，PAF患者的LF、HF和LF/HF值分别为747±277 ms²、387±94 ms²和2.9±0.6，正常人分别为1316±315 ms²、698±148 ms²和2.8±0.6（LF和HF，p < 0.05）。在TT1期间，PAF患者的LF、HF和LF/HF值分别为1243±432 ms²、302±88 ms²和7.7±2.4，正常人分别为1992±398 ms²、333±76 ms²和7.8±0.98（LF，p < 0.05）。在TT2期间，PAF患者的LF、HF和LF/HF值分别为871±256 ms²、242±51 ms²和4.7±0.9，正常人分别为1263±335 ms²、317±108 ms²和8.6±0.68（LF/HF，p < 0.05）。HRV的动态变化表明，PAF患者在TM或TT2期间LF和HF值无显著变化，LF/HF在TM期间无变化，但在TT1和TT2期间升高。
PAF患者在直立位时HRV存在改变，TM期间LF和HF功率降低，HUT开始几分钟内无显著变化。这些发现表明，小波变换分析在评估自主心脏调节时可能提供新的见解，并突出PAF中ANS紊乱的存在。
