Watanabe Eiichi, Arakawa Tomoharu, Uchiyama Tatsushi, Tong MaoQing, Yasui Kenji, Takeuchi Hiroshi, Terasawa Toshiaki, Kodama Itsuo, Hishida Hitoshi
Division of Cardiology, Department of Internal Medicine, Fujita Health University School of Medicine, Toyoake, Japan.
Heart Rhythm. 2007 Aug;4(8):999-1005. doi: 10.1016/j.hrthm.2007.04.019. Epub 2007 Apr 27.
In patients with chronic heart failure (CHF), circadian variability of RR and QT intervals may be altered because of neurohumoral activation and functional and structural remodeling of the heart.
The aim of this study was to evaluate the prognostic significance of circadian variability of the RR and QT intervals and QT dynamicity (QT/RR slope) in CHF patients.
We prospectively enrolled 121 patients with stable CHF in sinus rhythm (age 67 +/- 14 years, mean +/- SD; range 34 to 87 years). The RR, QT, and rate-corrected QT (QTc) intervals and the QT/RR slope measured from 24-hour Holter electrocardiogram were fitted by cosine curves.
During the follow-up period of 34 +/- 17 months, 40 (33%) patients died of cardiac causes, 10 of which were sudden. All patients showed significant circadian rhythms in the RR, QT, and QTc intervals and the QT/RR slope by cosine-curve fitting. In addition to the expected higher heart rate, longer QT interval, and steeper QT/RR slope, we found that patient who died of cardiac causes had reduced circadian variability of QT interval (10 +/- 10 ms vs 21 +/- 13 ms) and a later maximum RR interval (4.1 +/- 0.9 AM vs 2.3 +/- 2.1 AM) compared with survivors, among many other statistically significant circadian parameter differences. These 2 parameters were independent predictors of cardiac death in multivariate Cox proportional hazards regression analysis.
Circadian variability analyses of Holter-derived RR and QT intervals may provide prognostic information beyond that provided by 24-hour averages of these parameters.
在慢性心力衰竭（CHF）患者中，由于神经体液激活以及心脏的功能和结构重塑，RR间期和QT间期的昼夜变异性可能会发生改变。
本研究旨在评估CHF患者中RR间期、QT间期的昼夜变异性以及QT动态变化（QT/RR斜率）的预后意义。
我们前瞻性纳入了121例窦性心律的稳定CHF患者（年龄67±14岁，均值±标准差；范围34至87岁）。通过余弦曲线拟合从24小时动态心电图测量的RR间期、QT间期、心率校正QT（QTc）间期以及QT/RR斜率。
在34±17个月的随访期内，40例（33%）患者死于心脏原因，其中10例为猝死。通过余弦曲线拟合，所有患者的RR间期、QT间期、QTc间期以及QT/RR斜率均显示出显著的昼夜节律。除了预期的较高心率、较长QT间期和较陡的QT/RR斜率外，我们发现与存活者相比，死于心脏原因的患者QT间期的昼夜变异性降低（10±10毫秒对21±13毫秒），最大RR间期出现时间较晚（凌晨4.1±0.9点对凌晨2.3±2.1点），还有许多其他具有统计学意义的昼夜参数差异。在多变量Cox比例风险回归分析中，这两个参数是心脏死亡的独立预测因素。
对动态心电图得出的RR间期和QT间期进行昼夜变异性分析，可能提供超出这些参数24小时平均值所提供的预后信息。
