Stein Phyllis K, Domitrovich Peter P, Kleiger Robert E
Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, Mo 63108, USA.
Am Heart J. 2004 Feb;147(2):309-16. doi: 10.1016/s0002-8703(03)00520-9.
Decreased heart rate variability (HRV) is often assumed to be associated with mortality in all patients after myocardial infarction (MI), independent of clinical factors or time after MI.
HRV was determined from Holter tapes in the Cardiac Arrhythmia Suppression Trial (CAST). Patients were 71 +/- 120 days after MI. A total of 735 pre-therapy tapes were analyzed in patients who had ventricular premature contractions (VPCs) suppressed on the first treatment. The period of follow-up was 362 +/- 243 days (69 deaths). The association of clinical and demographic factors and 24-hour, daytime, and nighttime HRV to mortality in all patients, patients without coronary artery bypass graft (CABG) surgery between the qualifying MI and the Holter monitoring, and patients with neither CABG nor diabetes mellitus was determined with univariate Cox regression analysis.
For the entire group and the subgroup without CABG, the strongest association was with increased daytime normalized high frequency power (NHF day). Further excluding patients with diabetes mellitus strengthened the association of HRV with mortality rate. Decreased natural logarithm (ln) 24-hour total and ultra low frequency (ULF) power were the strongest predictors of mortality. The best cutoff point for ln ULF for separating survivors and non-survivors was determined. After including a history of MI, congestive heart failure, or both as co-factors, ln ULF < or =7.85 identified patients at approximately 4-times the relative risk of mortality, but did not risk-stratify patients without prior MI or history of congestive heart failure.
HRV predicts mortality rate in a broad range of times after MI. Excluding patients with CABG after MI or with diabetes mellitus significantly strengthens the association of HRV with mortality. HRV measures beyond the peri-infarction period, with clinical factors, can identify subgroups at an elevated risk of mortality.
心率变异性（HRV）降低通常被认为与心肌梗死（MI）后所有患者的死亡率相关，与临床因素或MI后的时间无关。
在心律失常抑制试验（CAST）中，通过动态心电图记录来测定HRV。患者在MI后71±120天。对首次治疗时室性早搏（VPC）得到抑制的患者共735份治疗前的动态心电图记录进行了分析。随访期为362±243天（69例死亡）。通过单因素Cox回归分析确定了临床和人口统计学因素以及24小时、白天和夜间HRV与所有患者、在符合条件的MI与动态心电图监测之间未进行冠状动脉搭桥术（CABG）的患者以及既未进行CABG也未患糖尿病的患者死亡率之间的关联。
对于整个组以及未进行CABG的亚组，最强的关联是白天标准化高频功率（NHF日）增加。进一步排除糖尿病患者增强了HRV与死亡率之间的关联。24小时总自然对数（ln）和超低频（ULF）功率降低是死亡率的最强预测因素。确定了用于区分存活者和非存活者的ln ULF的最佳截断点。在将MI病史、充血性心力衰竭或两者作为共同因素纳入后，ln ULF≤7.85可识别出死亡相对风险约为4倍的患者，但不能对无既往MI或充血性心力衰竭病史的患者进行风险分层。
HRV可预测MI后广泛时间段内的死亡率。排除MI后进行CABG的患者或糖尿病患者可显著增强HRV与死亡率之间的关联。MI后梗死周围期以外的HRV测量结合临床因素可识别出死亡风险升高的亚组。
