Zhao Ruifu, Li Dan, Zuo Ping, Bai Rong, Zhou Qiang, Fan Jingjing, Li Chengpeng, Wang Lin, Yang Xiaoyun
Department of Cardiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Ann Noninvasive Electrocardiol. 2015 Mar;20(2):158-66. doi: 10.1111/anec.12189. Epub 2014 Aug 12.
Deceleration capacity (DC) is a newly found predictor of mortality after myocardial infarction. Age-, gender-, and circadian rhythm-related differences in DC may limit its predictive value, which should be considered in clinical settings.
DC, average heart rate, and HRV parameters, including 24 hours, awaking state (15:00-20:00) and sleeping mode (00:00-05:00) strips from 24 hours Holter recordings in 636 subjects without heart diseases were examined. Heart rate variability was analyzed in time domains (standard deviation of all normal-to-normal intervals [SDNN], normal-to-normal RR intervals in all 5-minute segments [SDANN], and root mean square successive difference [RMSSD]).
The DC, SDNN, SDANN, RMSSD, and heart rate decreased with age. Deceleration capacity was significantly lower in patients greater than 50 years of age. The largest decrease of SDNN, SDANN, and RMSSD occurred in patients 30-39 years of age. The values of SDNN, SDANN, and DC of women were lower than that of men in the young and middle-aged groups, but age-related decrease of DC in men was greater than that in women. Heart rate of women was significantly higher than that of men in younger subjects, especially in a sleeping mode. There were higher values of DC and RMSSD during sleeping than that during a waking state.
The age, gender, and circadian rhythm may be useful when evaluating cardiac autonomic function and need to be considered when evaluating DC and HRV in clinical and scientific researches.
减速能力（DC）是新发现的心肌梗死后死亡率的预测指标。DC在年龄、性别和昼夜节律方面的差异可能会限制其预测价值，临床应用中应予以考虑。
对636名无心脏病受试者24小时动态心电图记录中的DC、平均心率和心率变异性参数进行检测，包括24小时、清醒状态（15:00 - 20:00）和睡眠状态（00:00 - 05:00）时段。在时域分析心率变异性（全部正常RR间期标准差[SDNN]、每5分钟时段正常RR间期均值[SDANN]和相邻RR间期差值的均方根[RMSSD]）。
DC、SDNN、SDANN、RMSSD和心率随年龄增长而降低。50岁以上患者的减速能力显著降低。SDNN、SDANN和RMSSD在30 - 39岁患者中下降幅度最大。在中青年组中，女性的SDNN、SDANN和DC值低于男性，但男性DC随年龄的下降幅度大于女性。年轻受试者中女性心率显著高于男性，尤其是在睡眠状态下。睡眠期间的DC和RMSSD值高于清醒状态。
在评估心脏自主神经功能时，年龄、性别和昼夜节律可能具有参考价值，在临床和科研中评估DC和心率变异性时需要加以考虑。
