阵发性房颤患者房性早搏后心率震荡的临床意义

目的探讨房性早搏（房早）后心率震荡（HRT）在评价阵发性房颤发作前自主神经短暂变化中的意义。方法24h动态心电图证实为阵发性房颤的患者共56例,用闪光卡经解压和扫描,记录房颤开始时间。（1）分析一天中的3个时段：上午（6～10点）、下午（13～17点）和夜间（24～4点）房早HRT的变化。各时段分别按顺序入选3个房早,计算心率震荡指标：震荡初始（TO。）及震荡斜率（Ts。）的数值。（2）比较阵发性房颤发作前、后1hHRT指标TOA、TSA及心率变异性指标：平均正常RR间期的标准差（SDNN）、低频成分（LF）、高频成分（HF）、低频／高频比值（LF／HF）的变化。结果（1）房颤发作前1hTOA、TS．均较发作后1h明显增高,（0．47±0．32）％VS（0．24±0．18）％及（16±6）ms／RRVS（13±4）ms／RR（P〈0．05）。HRV各指标在PAF发作前后无明显差异。（2）TOA、TSA夜间均较上午明显增高,（1．24-0．6）％VS（0．8±0．4）％及（17±6）ms／RRVS（14±4）ms／RR（P〈0．05）。（3）PAF在夜间发作最多,其次是下午。结论（1）提示房早可能引起迷走神经抑制反应缺失,甚至发生一过性迷走神经的兴奋性增强,导致房颤发作。（2）应用房早后HRT评价阵发性房颤发作前自主神经的变化,在PAF发作前异位搏动较多的情况下,可能会优于心率变异性,具有一定的临床意义。

Investigation of heart rate turbulence after atrial premature beats before onset of paroxysmal atrial fibrillation

OBJECTIVE: To discuss the clinical significance of heart rate turbulence (HRT) after atrial premature beats in accessing the temporal changes of vagus nerve before the onset of paroxysmal atrial fibrillation. METHODS: The HRT parameters: turbulence onset (TOA) and turbulence slope (TSA) after atrial premature impulses occurring 0 to 60 min before and after the onset of AF 56 patients with atrial fibrillation (AF). The heart rate variability (HRV) time domain parameter SDNN and the frequency-domain parameters, low frequency (LF), high frequency (HF), and LF/HF ratio were also analyzed. TOA and TSA were calculated for 3 periods reflecting morning hours (6-10 am), afternoon hours (1-5 pm), and night hours (0-4 am). RESULTS: (1) The TOA and TSA were significantly higher 1 h preceding AF than 1 h after AF(0.47+/-0.32 vs 0.24+/-0.18 and 16+/-6 vs 13+/-4, both P<0.05). The HRV time domain parameters and frequency-domain parameters did not change remarkably after the onset of PAF. (2) The TOA and TSA were significantly higher in night hours than in morning hours (1.2+/-0.6 vs 0.8+/-0.4 and 17+/-6 vs 14+/-4 respectively, both P<0.05), the two parameters of HRT maintained significant circadian variations. CONCLUSION: Vagal inhibition in response to premature atrial excitation is absent and transient enhancement of vagal outflow would occur before AF. HRT before atrial premature beats is of significance in accessing the changes of autonomic nervous system before onset of AF.