Stein P K, Domitrovich P P, Kleiger R E, Schechtman K B, Rottman J N
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.
Clin Cardiol. 2000 Mar;23(3):187-94. doi: 10.1002/clc.4960230311.
Clinical and demographic determinants of heart rate variability (HRV), an almost universal predictor of increased mortality, have not been systematically investigated in patients post myocardial infarction (MI).
The study was undertaken to evaluate the relationship between pretreatment clinical and demographic variables and HRV in the Cardiac Arrhythmia Suppression Trial (CAST).
CAST patients were post MI and had > or =6 ventricular premature complexes/h on pretreatment recording. Patients in this substudy (n = 769) had usable pretreatment and suppression tapes and were successfully randomized on the first antiarrhythmic treatment. Tapes were rescanned; only time domain HRV was reported because many tapes lacked the calibrated timing signal needed for accurate frequency domain analysis. Independent predictors of HRV were determined by stepwise selection.
Coronary artery bypass graft surgery (CABG) after the qualifying MI was the strongest determinant of HRV. The markedly decreased HRV associated with CABG was not associated with increased mortality. Ejection fraction and diabetes were also independent predictors of HRV. Other predictors for some indices of HRV included beta-blocker use, gender, time from MI to Holter, history of CABG before the qualifying MI, and systolic blood pressure. Decreased HRV did not predict mortality for the entire group. For patients without CABG or diabetes, decreased standard deviation of all NN intervals (SDANN) predicted mortality. Clinical and demographic factors accounted for 31% of the variance in the average of normal-to-normal intervals (AVGNN) and 13-26% of the variance in other HRV indices.
Heart rate variability post MI is largely independent of clinical and demographic factors. Antecedent CABG dramatically reduces HRV. Recognition of this is necessary to prevent misclassification of risk in patients post infarct.
心率变异性（HRV）几乎是死亡率增加的通用预测指标，但其临床和人口统计学决定因素在心肌梗死（MI）患者中尚未得到系统研究。
本研究旨在评估心律失常抑制试验（CAST）中预处理临床和人口统计学变量与HRV之间的关系。
CAST患者为心肌梗死后患者，预处理记录时每小时室性早搏≥6次。本亚组研究中的患者（n = 769）有可用的预处理和抑制磁带，并在首次抗心律失常治疗时成功随机分组。磁带重新扫描；仅报告时域HRV，因为许多磁带缺乏准确频域分析所需的校准定时信号。通过逐步选择确定HRV的独立预测因素。
合格心肌梗死后的冠状动脉旁路移植术（CABG）是HRV的最强决定因素。与CABG相关的HRV显著降低与死亡率增加无关。射血分数和糖尿病也是HRV的独立预测因素。HRV某些指标的其他预测因素包括β受体阻滞剂的使用、性别、从心肌梗死到动态心电图监测的时间、合格心肌梗死前的CABG病史以及收缩压。HRV降低并不能预测整个组的死亡率。对于没有CABG或糖尿病的患者，所有正常到正常间期的标准差（SDANN）降低可预测死亡率。临床和人口统计学因素占正常到正常间期平均值（AVGNN）方差的31%，占其他HRV指标方差的13 - 26%。
心肌梗死后的心率变异性在很大程度上独立于临床和人口统计学因素。既往CABG会显著降低HRV。认识到这一点对于防止梗死患者风险分类错误是必要的。
