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ogical link among abnormal HRV, autonomic tone, and arrhythmogenesis, the present data show that HRV may be a better marker of nonarrhythmic mortality. AJ, et al. Circulation. 2020。但尚需更多資料進(jìn)一步明確其臨床應(yīng)用價值。 1977 ? 檢測原理 :由于這種電信號非常微弱,一般在幾十微伏以下,故常規(guī)心電圖難以捕捉到,信號平均心電圖( SAECG)則可以記錄到該電活動信號。V ? 意義: 大量的資料證實(shí),信號平均心電圖可用于識別既往心梗后發(fā)生心臟性猝死的高危患者。 ? 檢測方法 : 選最大 QT(QTmax)、最小 QT(QTmix)導(dǎo)聯(lián)連續(xù)測量三個心動周期,取其平均 值為 QTmax、 QTmix間期,然后計算: QTd=QTmax QTmin. ? 正常值 :目測 QTd:正常參考值< 50ms, 50~ 70ms 之間有參考價值,以> 70ms有診斷價值。尚需進(jìn)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。 ? 首先發(fā)表的作者: Mines GR ( Italy), J Physiol. 1913 46 :349; Smith JM ( USA), Circulation, 1988, 77: 110 ? 檢測對象 : 心肌的復(fù)極異常和心肌的易損性 ? 檢測方法 : 頻域法; 時域法 ? 正常值 : 1. 常規(guī)心電圖判斷顯性 T波電交替陽性參考標(biāo)準(zhǔn): 同一導(dǎo)聯(lián) T波的形態(tài)、振幅、極性出現(xiàn)逐搏交替變化,其中 T波振幅逐搏相差 ≥。但為了明確在臨床實(shí)踐中如何利用這項技術(shù),還需要提供更多的相關(guān)信息。356:651–652. (九)竇性心率震蕩 ? 定義 :正常人,當(dāng)自主神經(jīng)功能正常時,一次室早后常有竇性心律先加速,后減速的雙相式變化,這種現(xiàn)象稱為竇性心率震蕩( Heart Rate Tuburlence,HRT)。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。但尚需要進(jìn)一步的研究,以便明確 HRT在危險分層中是否具有臨床應(yīng)用價值 . Heart Rate Turbulence ? in an ATRAMI substudy,[1] there was a relative risk of 4 in multivariate analysis. A posite autonomic index, which included BRS and timedomain measures of HRV, increased the relative risk to 8. A smaller number of studies of patients with nonischemic dilated cardiomyopathy, chronic congestive heart failure, or hypertrophic cardiomyopathy (HCM) and patients undergoing revascularization have also suggested a predictive value of heart rate turbulence. ? In the Marburg Cardiomyopathy Study of 242 patients with nonischemic dilated cardiomyopathy, heart rate turbulence onset was a multivariate predictor of transplantfree survival (relative risk , 95% CI to ) but not of arrhythmic events. A, et al. Am J Cardiol. 2020。36:2247–2253. SH, et al. J Am Coll Cardiol. 2020。 3.動態(tài)心電圖時域分析法參考標(biāo)準(zhǔn): 為頻域分析方法的 4倍,即 Valt≥, K≥。以往 TWA幅度為毫伏級( mV),而新近 TWA幅度為微伏級(181。國內(nèi)外公認(rèn) QTd正常值< 50 ms。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?。 ? 檢測方法 : 1.有創(chuàng)性直接記錄法: ( 1)心內(nèi)膜標(biāo)測;( 2)心外膜標(biāo)測 2.無創(chuàng)性體表記錄法: ( 1) 時域法; ( 2)頻域法 ? 正常值 : ① 信號平均后的 QRS波群時限( QRSD ) ≥120ms; ② QRS終末部 40181。85: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。健康個體靜注苯福林 25~100μ g, 一般收縮壓升高> 20 mmHg, RR間期延長> 10 ms/mmHg。 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。 12ms ④ 三角指數(shù)( TRI): 37177。44:820–826. (四)心率變異性 ? 定義 : 心率變異性( heart rate variability,HRV)是