【正文】 he groups. ? Cammetal [147]studied 3717 postMi pts with left ventricular dysfunction and characterized them into low and highrisk groups on the basis of the triangular index of HRV. Although the trial was designed to examine the effects of an antiarrhythmic drug (azimilide) on survival, data on the prognostic importance of HRV were also reported. By multivariate analysis, low HRV increased risk of allcause mortality with a hazard ratio of (95% CI to )。 ? 首先發(fā)表的作者： Hon和 Lee （ USA）， Am J Obstet Gynecol, 1965。51:507–512. HC, et al. Circulation. 1996。117:151159. 心動過緩 17% VT 62% 原發(fā)性 VF 8% 尖端扭轉(zhuǎn)性 VT 13% （二） 心律失常是 SCD的主要原因 一、心臟猝死的概況 （三）心肺復(fù)蘇時間與成功率的關(guān)系 Cummins RO. Annals Emerg Med. 1989。 2020. 2 Adapted from Heikki et al. N Engl J Med, Vol. 345, No. 20, 2020. 3 Myerberg RJ. Heart Disease, A Textbook of Cardiovascular Medicine. 6th ed. P. 895. 一、心臟猝死的概況 Albert CM. Circulation. 2020。10:73– 80. [4] Iuliano S, et al. Am Heart J. 2020。104:1911–1916. ? A phenomenon related to heart rate recovery is ventricular ectopy during recovery, which has also been hypothesized to reflect parasympathetic activity. Occurrence of frequent or severe ventricular ectopy during the first 5 minutes of recovery after exercise has been linked to risk of death in pts without and with heart failure and/or coronary artery disease.[1,2] JP, et al. N Engl J Med. 2020。但目前的數(shù)據(jù)表明 HRV可能是預(yù)測非心律失常死亡的更好指標(biāo)。但尚需更多資料進一步明確其臨床應(yīng)用價值。V ? 意義： 大量的資料證實，信號平均心電圖可用于識別既往心梗后發(fā)生心臟性猝死的高?；颊?。尚需進一步的研究來確定這些參數(shù)的在 SCD危險性分層中的臨床意義。但為了明確在臨床實踐中如何利用這項技術(shù)，還需要提供更多的相關(guān)信息。119:e391e479 2020 ACC/AHA 心衰指南 ? Approximately 50% to 70% of patients with low EF and symptomatic HF have episodes of nonsustained VT on routine ambulatory electrocardiographic monitoring。36:2247–2253. SH, et al. J Am Coll Cardiol. 2020。以往 TWA幅度為毫伏級（ mV），而新近 TWA幅度為微伏級（181。目前資料尚不支持常規(guī)應(yīng)用信號平均心電圖識別 SCD的高?；颊摺?5:I77I91. （六）心室晚電位 ? 定義 :心室晚電位（ ventricular late potential， VLP）是指出現(xiàn)在 QRS波群終末部、 ST段內(nèi)的一種高頻、低振幅、多形性碎裂電活動。 短程心率變異性 ? In pts with chronic heart failure, La Rovere [1]analyzed 8minute recordings during quiet rest with spontaneous breathing or controlled breathing. A diminished ratio of low to highfrequency power during spontaneous breathing, a standard deviation of RR intervals 15 ms, and diminished lowfrequency power during controlled breathing were univariate predictors of arrhythmic mortality. In multivariate analysis, diminished lowfrequency power during controlled breathing was associated with a 5fold increase in arrhythmic mortality. The bination of preserved lowfrequency power and fewer than 86 ventricular premature beats (VPBs) per hour was associated with a 3% SCD risk pared with 23% for the remainder of the population. MT,et. Circulation. 2020。44:820–826. （四）心率變異性 ? 定義 : 心率變異性（ heart rate variability,HRV）是指逐次心動周期之間 的細微的時間變化及其規(guī)律。93:85–90 SK, et al. Am J Cardiol. 1983。s de Luna A. Am Heart J. 1989。107:20962101. 12% 其他心臟病 88% 心律失常 Bay233。143:1085–1091. （二）室性早搏和非持續(xù)性室速 ? Patients with nonischemic cardiomyopathy are at increased risk of SCD and frequently have highgrade ventricular ectopy and NSVT [] ? In GESICA trial, which included a majority of pts with nonischemic cardiomyopathy, confirmed the prevalence of ventricular arrhythmias on AECG