致QT延长药物的研究 Jean-Philippe Couderc, PhD, MBA Online Symposium ISHNE 2007 University of Rochester Medical Center Heart Research Follow-Up Program, Cardiology Department Rochester, NY, USA Online Symposium ISHNE 2007

背 景 I 获得性的长QT综合征同许多药物相关,而这些药物因同多种心律失常事件及心源性猝死有关,已退出市场. 这些药物大多作用于HERG，导致心肌细胞内特定钾电流(IKr)减少及延迟心室复极过程. The prolongation of the QT interval from the surface electrocardiogram (ECG) is currently used as a surrogate marker of the potential torsadogenic properties of cardiac and non-cardiac drugs. Following several cases of cardiac death reported in individuals on the non-cardiac drugs terfenadine* and cisapride**, the US Food and Drug Agency (FDA) currently recommends to pharmaceutical companies that all new compounds should be tested for their potential QT prolonging effect. (*) Woosley RL, Chen Y, Freiman JP, Gillis RA. Mechanism of the cardiotoxic actions of terfenadine. JAMA 1993 Mar 24;269(12):1532-6. (**) Mohammad S, Zhou Z, Gong Q, January CT. Blockage of the HERG human cardiac K+ channel by the gastrointestinal prokinetic agent cisapride. Am J Physiol 1997 Nov;273(5 Pt 2):H2534-H2538.

目前将体表心电图(ECG)上QT间期延长作为心脏或非心脏性药物的致尖端扭转性室速潜能的一种标志。最近，继非心脏性药物特非那定. 及西沙比利 目前将体表心电图(ECG)上QT间期延长作为心脏或非心脏性药物的致尖端扭转性室速潜能的一种标志。最近，继非心脏性药物特非那定*及西沙比利**致心源性猝死的几项各案报道后, 美国食品药品管理局(FDA)建议制药公司对所有新药都需测定其潜在的致QT延长作用. (*) Woosley RL, Chen Y, Freiman JP, Gillis RA. Mechanism of the cardiotoxic actions of terfenadine. JAMA 1993 Mar 24;269(12):1532-6. (**) Mohammad S, Zhou Z, Gong Q, January CT. Blockage of the HERG human cardiac K+ channel by the gastrointestinal prokinetic agent cisapride. Am J Physiol 1997 Nov;273(5 Pt 2):H2534-H2538.

背 景 II 上述药物对体表心电图上QT间期的延长并非一成不变,提示以心电图为标记的局限性. 因此，除测定QT间期外，设计一种方法——通过依靠其他参数来评价药物诱导的致复极异常心脏毒性以及反映IKr的阻滞程度显得非常重要。 It is well-accepted that a QTc interval beyond 500 msec is a clear predisposing factor for the occurrence of torsades de pointes (TdPs) in both congenital and acquired form of LQTS, but the presence of a prolonged QT-interval duration below 500 msec is associated with a less clear-cut risk. The majority of patients with acquired or congenital LQTS show QTc<500ms, a value with equivocal diagnostic and prognostics significance (*). The development of new biomarkers complementing the QT interval measurements for the identification of a predisposition to ventricular arrhythmias in congenital LQTS and for the assessment of the IKr-inhibitory effect of drugs is of major interest. This presentation will describe 5 studies implemented during the past 2-3 years at the Heart Research Follow-up Program in Rochester NY. Several of these studies were done in collaboration with pharmaceutical companies and CROs. (*) Couderc JP, McNitt S, Xia J, Zareba W, Moss AJ. Repolarization morphology in adult LQT2 carriers with borderline prolonged QTc interval. Heart Rhythm 2006 Dec;3(12):1460-6.

本文阐述了在过去2-3年间纽约罗彻斯特心脏随访研究项目中的五个研究. 其中多个研究与药物公司及CROs合作进行. 先天性或获得性LQTS中,QTc超过500ms作为尖端扭转型室速(TdPs)发生的明确易感因素已被广为接受,而QTc小于500ms时室速的发生风险相对降低. 大多数获得性或先天性LQTS患者表现为QTc<500ms,该临界值对明确诊断诊及预后评估的意义都模棱两可(*). 用以识别先天性LQTS室性心律失常易感性并评价药物对IKr的抑制作用的新的生物标记物的出现,弥补了QT间期测量的不足，引起了人们极大的兴趣。 本文阐述了在过去2-3年间纽约罗彻斯特心脏随访研究项目中的五个研究. 其中多个研究与药物公司及CROs合作进行. (*) Couderc JP, McNitt S, Xia J, Zareba W, Moss AJ. Repolarization morphology in adult LQT2 carriers with borderline prolonged QTc interval. Heart Rhythm 2006 Dec;3(12):1460-6.

我们已经在先天性LQTS中掌握了什么?

T波形态同先天性 LQTS 基于对153个家系成员连锁标记的观察: 染色体 3 (n=47), 染色体 7 (n=30), 染色体 11 (n=76) The link between morphological changes of T-wave on the surface ECG and abnormal kinetics of repolarization ion currents is supported by the observations published in 1995 on the phenotype-genotype correlation from patients with the congential long QT syndrome (LQTS).* Patients with mutations in the SCN5A sodium channel gene on chromosome 3 have a distinctive, late-appearing T wave that is clearly different from the low-amplitude, moderately delayed T wave observed in affected patients who are carriers of the abnormal gene on chromosome 7 (HERG/KCNH2 mutation, LQT2). Both of these repolarization patterns are different from the broad-based, prolonged T-wave pattern found in patients who are carriers of the abnormal gene on chromosome 11 (KCNQ1, LQT1). (*) Moss AJ, Zareba W, Benhorin J et al. ECG T-wave patterns in genetically distinct forms of the hereditary long QT syndrome. Circulation. 1995;92:2929-2934. Moss AJ, Zareba W, Benhorin J et al. ECG T-wave patterns in genetically distinct forms of the hereditary long QT syndrome. Circulation. 1995;92:2929-2934.

1995年发表的先天性 LQTS患者表型－基因型的相关性研究. 支持体表心电图上T波形态学的改变同复极离子流异常动力学的联系 1995年发表的先天性 LQTS患者表型－基因型的相关性研究*支持体表心电图上T波形态学的改变同复极离子流异常动力学的联系.3号染色体SCN5A钠通道基因突变的患者有特征性的晚发T波,而这同7号染色体上异常基因携带者(HERG/KCNH2 突变, LQT2) 的振幅低、中度延迟的T波明显不同，这两种复极形式同11号染色体异常基因携带者(KCNQ1, LQT1)的基底宽、延迟的T波也不相同. (*) Moss AJ, Zareba W, Benhorin J et al. ECG T-wave patterns in genetically distinct forms of the hereditary long QT syndrome. Circulation. 1995;92:2929-2934.

T波形态学研究的合理性 研究 2: T波形态是否能鉴别基因特异性的LQT综合征? LQTS的早期诊断很必要, 因为多种预防性治疗可以有效减少致死性心律失常的发生风险. 尽管基因检测是验证LQTS患者异常基因的金标准,但其并不容易实施(患者拒绝),过于昂贵,或确定结果. 因此,评价电脑ECG对LQTS疑似患者的临床初筛(先于基因分型)是否有效显得非常重要,该研究有两个特殊目的: 研究 1: T波形态学能否增加QT间期接近正常的LQTS基因突变携带者的识别率？ 研究 2: T波形态是否能鉴别基因特异性的LQT综合征? Early diagnosis of LQTS is critical because various prophylactic therapies can effectively reduce the risk for life-threatening arrhythmias: surgical denervation, beta-blocker medications cardiac pacemakers and cardioverter-defibrillator implantation. The diagnostic methods rely on the patient’s cardiac history, heart rate, and prolongation of the heart-rate corrected QT interval (QTc). First, several investigations based on the International Registry for the Congenital LQTS have revealed that the presence of a QTc prolongation is not a perfect surrogate marker for identifying patients affected by the LQTS and it is useless for the identification of the type of mutation (KVLQT1, KCNH2, SCN5A, ..). From surface ECGs: 10-15% of LQTS patients do not have an abnormal QTc prolongation. (1) Consequently, one may question the interest of detecting abnormal morphology of the T-wave as a phenotypic expression of the presence of the LQTS mutation: Second, identifying the presence of the LQTS is not enough and information about the type of mutation of a patients significantly help optimizing therapeutic strategies for these patients. Although genetic testing is the gold standard for the verification of the underlying gene abnormality in LQTS patients, it is frequently not accessible (patients’ refusal), too expensive, or results could be delayed. Consequently, it is important to assess whether computerized ECG might be helpful in clinical pre-screening (prior to genotyping) of individuals suspected for LQTS. (1) Zareba W, Moss AJ, Schwartz PJ et al. Influence of genotype on the clinical course of the long-QT syndrome. International Long-QT Syndrome Registry Research Group. N Engl J Med 1998 October 1;339(14):960-5

LQTS的早期诊断很必要, 因为不同预防性治疗可以有效减少致死性心律失常的发生风险:外科去神经、beta-受体阻滞剂、心脏起搏器及植入型除颤器.诊断依靠患者的心脏病史、校正心率后QTc的延长. 首先,多个国际注册的先天性LQTS的研究显示:QTc的延长并不能作为识别LQTS的最佳指标,也无助于识别基因突变类型(KVLQT1, KCNH2, SCN5A……). 体表心电图上: 10-15% 的LQTS患者并没有异常的QTc延长 (1),因此,人们可能会质疑将异常T波形态作为LQTS突变表型的益处。

其次,这些患者中,仅确定是否有LQTS是不够的,明确患者的突变类型极大的利于选择合适的治疗策略 其次,这些患者中,仅确定是否有LQTS是不够的,明确患者的突变类型极大的利于选择合适的治疗策略.尽管基因检测是明确LQTS患者基因异常的金标准,但其并不容易被接受(患者拒绝),过于昂贵,或确定结果太慢. 因此，评价电脑ECG用于LQTS疑似患者的临床初筛(先于基因分型)的有效性显得非常重要。 (1) Zareba W, Moss AJ, Schwartz PJ et al. Influence of genotype on the clinical course of the long-QT syndrome. International Long-QT Syndrome Registry Research Group. N Engl J Med 1998 October 1;339(14):960-5

本研究基于先天性LQTS的国际注册研究资料 研究 1 LQT2患者的复极波形 本研究基于先天性LQTS的国际注册研究资料 STUDY #1: In the LQT2 syndrome, 11% of LQT2 patients present normal heart-rate corrected QT interval (0.44 sec) and at least half of LQT2 patients have QTc ≤0.47 sec. Therefore, there is a need for developing better ECG diagnostic techniques than QT prolongation measurements to identify subjects suspected for LQT2. Several methods have been used to replace or complement the hereditary or acquired QT prolongation risk factor by other non-invasive markers. These techniques were based on static and dynamic aspects of repolarization: prolongation of the T-peak to T-end (TpTe) and QT dispersion, abnormal T-wave morphology, RT hysterisis from exercise testing, microvolt-level T-wave alternans, and repolarization variability. In this study, we investigated a large cohort of genotyped LQT2 carriers and non-carriers from the International Registry for the LQTS in order to determine the role of the T-wave morphology in the identification of LQT2 patients. We hypothesized that a phenotypic expression of the KCNH2 (HERG) mutation on the surface ECG provides complementary information to QT interval prolongation and may help identify LQT2 patients. ECG analysis of additional readily available parameters might assist physicians in their bedside clinical diagnosis when there is a suspicion of LQTS. Couderc JP, McNitt S, Xia J, Zareba W, Moss AJ. Repolarization morphology in adult LQT2 carriers with borderline prolonged QTc interval. Heart Rhythm 2006 December;3(12):1460-6 Couderc JP, McNitt S, Xia X, Zareba W, Moss A.J. Discrimination of hERG carrier from non-carrier patients with borderline prolonged QTc intervals. Computers in Cardiology, Valencia Spain, IEEE Computers Press, 2005 p. 125-8

研究 #1: LQT2综合征中,11%的LQT2患者校正心率后QT间期正常(≤ 0.44s) ,至少一半的LQT2患者QTc ≤0.47s. 因此,很有必要开发一种比测量QT延长更好的心电图诊断技术来识别疑似LQT2.多种非侵入性标识已被用来替代或者补充那些遗传性或获得性致QT延长的危险因素.上述方法基于静态或动态的复极形态:T波顶点到T波终点(TpTe)的延长,QT离散度,异常T波形态,运动试验的RT滞后,微伏水平的T波电交替及复极变异性. 在本研究中,为确定T波形态在识别LQT2中的作用,我们调查了LQT2国际注册研究中的LQT2基因型携带者和非携带者大样本队列。 我们推测体表心电图中KCNH2(HERG)突变表型的表达是对QT间期延长的补充,可利于识别LQT2患者.合并使用其他已知的有效参数进行心电图分析可以帮助内科医生对LQTS疑似患者进行床旁临床诊断.

LQT2患者QT间期的分布 研究 1 所有 QTc 值 (n=159) 接近正常的QTc间期 (390 to 470 ms, n= 95) * Bazet 校正 QT 间期 The study population for the study# 1 consisted of patients with genetically tested KCNH2 mutation. This group encompasses 52 families from the International LQTS registry. Family members of genotyped LQTS probands were tested for proband identified mutation and were categorized as carriers or non-carriers. Subjects under 17 years of age were not included in the analysis because the T-wave morphology is age dependent and repolarization changes are frequently observed before adulthood.(*) The KCNH2 mutations were identified in each subject using standard genetic tests. All subjects provided informed consent for the genetic and clinical studies. We studied the distribution of the QTc values in this cohort. The distribution revealed a significant overlapping area in which both patients carrier and non-carrier of the LQT2 mutation reside. This “gray” area illustrates the limitation of the QT interval as marker of the presence of the LQTS. By selecting ECGs with QTc between 390 and 470 msec, we create a sub-group of individual with near-normal QT interval duration (60% of the initial study population). Digital standard 12-lead ECG tracings were available in these study populations. *B. Surawicz and S. R. Parikh, "Prevalence of male and female patterns of early ventricular repolarization in the normal ECG of males and females from childhood to old age," J. Am. Coll. Cardiol., vol. 40, no. 10, pp. 1870-1876, Nov.2002

应用数字标准12导心电图对此研究人群进行描记. 研究1由基因检查确定为KCNH2突变的人群组成. 本组包括国际LQTS注册研究中的52个家系. 经检测证实的遗传型LQTS家系成员被分为携带者和非携带者.本分析并没有包括17岁以下的受试者,因为T波形态与年龄有关,且成年前常观察到复极异常.(*).应用标准化基因检测确定每位受试者的KCNH2突变. 所有受试者签署基因和临床研究的知情同意书. 我们研究该人群中QTc值的分布.此分布显示LQT2突变携带者和非携带者之间有明显重叠区域. 该“灰色”区域解释了以QT间期作为LQTS标记的局限性. 选择QTc在390至470ms的心电图,我们建立了QT间期接近正常的亚组(最初研究人群的60%). 应用数字标准12导心电图对此研究人群进行描记. B. Surawicz and S. R. Parikh, "Prevalence of male and female patterns of early ventricular repolarization in the normal ECG of males and females from childhood to old age," J. Am. Coll. Cardiol., vol. 40, no. 10, pp. 1870-1876, Nov.2002

研究人群 非 -受体阻滞剂治疗 390≤QTc≤470 非携带者 携带者 N 90 69 46 49 女性 (%) 61.1 58.0 研究 1 研究人群 非 -受体阻滞剂治疗 390≤QTc≤470 非携带者 携带者 N 90 69 46 49 女性 (%) 61.1 58.0 78.3 59.2* 年龄 (岁) 32.914.4 37.817.0 32.4±13.8 36.7±16.6 既往CE 5.6 31.9* 6.5 26.5* 心率 (次/分) 71.713.8 67.012.6* 76.2±13.1 66.7±12.6* We focused our analysis on a sub-group of individuals without beta-blocking therapy and with near-normal QTc interval duration. The use of beta-blockers may affect the repolarization process and potentially affect the morphology of the T-wave since the potassium ion currents are know to be regulated by the nervous autonomic system. We focused our analysis on the 46 and 49 non-carrier and carrier of a KCNH2/HERG mutation. The number of female was significantly lower in the groups of LQT2 carriers. Also, as expected, the number of cardiac events was higher in patients carrying the mutation. They also present a lower heart rate (p<=0.05). CE: 心脏事件 * p≤0.05, † p≤0.01 非携带及携带人群进行比较

该研究集中分析无 -受体阻滞剂治疗及QTc接近正常的亚组 该研究集中分析无 -受体阻滞剂治疗及QTc接近正常的亚组.因为钾离子流可被自主神经系统调整,所以应用 -受体阻滞剂可以影响复极过程并潜在影响T波形态. 该研究分析了46名KCNH2/HERG基因突变携带者及49名非携带者. LQT2携带者中女性比例明显偏低. 同预期一致的是,基因突变携带者心脏事件发生率高,且心率偏低 (p<=0.05).

复极参数 研究 1 非携带者 携带者 人数 46 49 T波幅度(mV) 0.24±0.12 0.16±0.07* QT 峰 (ms) 293.9±24.5 336.2±33.6* QT (ms) 368.928.4 428.135.5* QTc (ms) 412.617.7 435.4±18.6* RR (ms) 807.1±136.2 972.7±149.1* R (mV/标准) -0.017±0.009 -.010±0.005* L (mV/标准) 0.013±0.006 0.006±0.003* TpTe (ms) 74.7±9.9 93.0±25.8* T 对称 0.80±0.36 0.76±0.38 This table presents the averages and standard deviations of the repolarization parameters measured from the ECG tracings of LQT2 carrier and non-carrier individuals (cohort of individuals with near-normal QTc interval duration). Most of the parameters reveal statistically significant differences between the two groups with a prolong QT interval, a lower T-wave amplitude and slower velocity of the repolarization fronts (up and down slope of the T-wave). As a note, the T-wave symmetry did not reveal any significant differences between groups with and without the mutation. T波对称是指T波左右支斜率的比率 * p<0.05

上表显示，测量LQT2携带者及非携带者(QTc接近正常)的心电图得到的复极参数的平均值及标准差 上表显示，测量LQT2携带者及非携带者(QTc接近正常)的心电图得到的复极参数的平均值及标准差.大部分参数提示两组间有统计学差异,如前者QT间期的延长更长、T波振幅更低、复极更慢(T波上升和下降斜率），但T波对称并没有提示两组有显著差异.

Log(p/(1-p))=-44.0+0.083QTc-0.013RR-318αL 研究 1 应用T波形态鉴别携带及非携带者 非 -受体阻滞剂治疗, 390≤QTc≤470 Multi-parametric statistical models were implemented to evidence the interest of using the morphology of the T-wave. In a stepwise logistic model, the use of the left slope of the T-wave improve the classification of ECG from individuals with and without the LQT2 mutation. The figure describes the Receiver Operating Characteristics (ROC) curves for three models based on QTc, RR and left slope of the T-wave. The logistic equation of the optimal model is provided at the bottom of the slide. The model was adjusted for gender. The main result from this preliminary study suggests that the morphology of the T-wave brings complementary information to QT prolongation when differentiating LQT2 carriers and non-carriers with borderline QTc. Our study showed significant alteration in T-wave morphology in patients carrying the KCNH2 mutation even when the QT interval of these patients was in near-normal range. Log(p/(1-p))=-44.0+0.083QTc-0.013RR-318αL 模型中校正性别

应用多参数统计模式验证T波形态的意义. 在逐步回归模式中,不管有无LQT2突变，T波左斜率可改善患者的心电图分级. 此图描述了以QTc,RR及T波左斜率为模式的ROC曲线.在幻灯片底部列出了最适模式的逻辑方程. 此模式经过性别校正. 该预初研究的主要结果证实，当用临界QTc区分LQT2携带及非携带者时,T波形态可作为QT延长的补充；QT间期接近正常的KCNH2基因突变携带者T波形态发生显著改变.

本研究基于先天性LQTS的国际注册研究资料 研究2 作为 LQTS表型表达的T波形态 本研究基于先天性LQTS的国际注册研究资料 STUDY #2: The long QT syndrome (LQTS) is an inherited arrhythmia disorder caused by genetically determined defects in ion channel structure and function. The LQTS patients are at high risk of sudden cardiac death due to the development of ventricular tachycardia degenerating in ventricular fibrillation and cardiac arrest. With increasing awareness of the LQTS among physicians and patients, there is growing number of patients with borderline QTc who are suspected for the disorder. There is clinical need for developing ECG methods assisting physicians in diagnosing LQTS patients and in providing indications regarding specific genotype. Although genetic testing remains the gold standard for verification of the underlying gene abnormality, it is frequently not accessible (patients’ refusal), too expensive, or results could be delayed. LQTS genotype frequently is associated with specific ECG phenotype, however, there is substantial variation and overlap in results of ECG phenotyping based on visual assessment of T wave morphology as well as there is substantial variance in penetrance of causative genes. Consequently, it is important to assess whether computerized ECG might be helpful in clinical pre-screening (prior to genotyping) of individuals suspected for LQTS. Discriminating gene-specific syndrome such as the LQT1 vs. LQT2 is of clinical importance since the prognosis and management might differ depending on findings. In this case, the QT/QTc prolongation is not a useful marker since the QT interval is similarly prolonged within the two groups. Vaglio M, Couderc JP, McNitt S, Zareba W, Moss AJ. ECG-based method for identifying kvLQT1/KCNE1 or HERG mutation in patients with the long QT syndrome. Annual Scientific Sessions of the American College of Cardiology February 21st, 2006, Atlanta, GA in JACC Vol. 47 no.4 (Supp A): 13A Vaglio M, Couderc JP, Xia X, Zareba W. Quantitative Repolarization Patterns Identifying KvLQT1 and KCNH2 Mutation in Patients with the Long QT Syndrome, Heart Rhythm 2007, in press.

研究 #2: LQTS是一种由离子通道结构和功能缺陷所致的遗传性心律失常. 由于LQTS患者室速可演变成室颤及心脏停搏,所以其心脏猝死的风险较高. 随着医生及患者对LQTS认识的增加,越来越多的处于QTc临界值的患者被怀疑患此疾病. 因此开发一种心电图方法以利于医生确诊LQTS,并明确不同基因型的临床需求越来越大.尽管基因检测是验证LQTS患者基因异常的金标准,但其并不易被实施(患者拒绝),过于昂贵,或确定结果太慢.LQTS基因型常同特殊心电图表型相关, 然而, 同致病基因的外显率相似，目测T波形态所得的心电图表型有极大的差别和重叠.

因此,评价电脑ECG用于LQTS疑似患者的临床初筛(先于基因分型)的有效性显得非常重要。 由于不同类型LQTs的预后和处理各异，因此临床上很有必要区分不同基因型如LQT1及LQT2。本病例中,因为两组QT间期都延长,所以QT/QTc的延长并不是有用的标记.

研究人群 研究 2 健康组 LQT1 LQT2 人数（女） 年龄（岁） Beta受体 阻滞剂(%) RR (ms) QT (ms) 38 (29%) 49 (71%) † 25 (76%) † 年龄（岁） 27.5 ± 8.1 34.3 ± 10.2 † 35.5 ± 9.4 † Beta受体 阻滞剂(%) 63 44 RR (ms) 767 ± 74 849 ± 110 † 837 ± 134 QT (ms) 360 ± 20 450 ± 38 † 466 ± 70 † QTc F (ms) 394 ± 16 478 ± 29 † 494 ± 49 † QTc B (ms) 413 ± 17 493 ± 29 † 510 ± 41 † The study population consisted of 49 LQT1 and 25 LQT2 carriers from 26 LQT1 families and 19 LQT2 families. The KCNH2 and KvLQT1 mutations were identified using standard genetic tests. Thirty-eight unrelated healthy subjects were included and used as a reference group. All individuals had a digital Holter recording for 24 hours: digital 12-lead Holter recorder H12 (H-12 recorder, Mortara Instrument, Milwaukee, WI). Slower heart rate and prolonged QT intervals characterized the ECG tracings of both LQT1 and LQT2 patients. Average values and standard deviations for overall diurnal period. Measurements are from lead V5. QTc B: heart-rate corrected QT using Bazett’s formula; QTc F: QTc corrected using Fridericia formula. †: p < 0.05 in comparison to healthy.

研究人群包括26个LQT1家系和19个LQT2家系中的49个LQT1和25个LQT2携带者 研究人群包括26个LQT1家系和19个LQT2家系中的49个LQT1和25个LQT2携带者. 标准基因检测方法确定KCNH2及KvLQT1 突变，38名无关的健康受试者作为对照. 所有个体行24小时Holter记录:12导数字记录器H12 (H-12 记录器, Mortara Instrument, Milwaukee, WI). 描记LQT1及LQT2患者慢心率及延长的QT间期的特征.

Holter ECG 记录 动态 Holter ECGs: 研究2 Holter ECG 记录 动态 Holter ECGs: Holter H12记录器提供12导心电图信号 (Mortara Instrument, Milwaukee, WI). 振幅分辨率: 12 bits (6.25 µV) 采样频率: 180Hz 心电图记录时间 : ~24 hours All the Holter ECGs were recorded for 24-hour using the same type of equipment: digital 12-lead Holter recorder H12 (H-12 recorder, Mortara Instrument, Milwaukee, WI) providing digital ECG signal at a sampling frequency of 180 Hz and with 12 bit amplitude resolution. The 8 original leads are recorded and the remaining 4 leads (augmented limb leads aVR, aVL, aVF and lead III) are calculated. Beat classification was performed using the H-Scribe scanning software (HScribe, Mortara Instrument, Milwaukee, WI) and manually reviewed and adjusted when necessary. The information about cardiac beat annotation was exported in XML format and integrated into the COMPAS software (COMPhrensive Analysis of the repolarization Segment software, University of Rochester Medical Center Rochester, NY) for the QT and T-amplitude measurements. To ensure stability of repolarization and increase signal-to-noise ratio, we adopted the following strategy: the Holter recordings were divided in sections of 10 continuous sinus beats. A representative beat (median beat) was computed from the consecutive 10 beats only if the section was preceded by stable heart rate within the previous five minutes. Heart rate stability required having less than 300 ms changes between continuous RR values within these preceding five minutes. Then, the 10-beat section was defined stable if the variation of the nine RR intervals remained into the range of values defined by ±10% of the average RR interval. The QT interval and T-amplitude measurements were based on the “stable representative beats” from lead II. 静态复极间期测量: 基于10次连续搏动的典型搏动 静态 :先前五分钟内的ΔRR<300 ms HR 稳定性 : |ΔRR|<10 % 窦性搏动

所有Holter心电图均用同类型仪器记录24小时:数字化12导记录器 H12 (H-12 记录器, Mortara Instrument, Milwaukee, WI) 提供180Hz采样频率及12bit振幅分辨率的数字心电图信号。8个原始导联做记录,剩余4导联 (加压肢体导联 aVR, aVL, aVF 及 III导) 做计算. 应用H-Scribe扫描软件(HScribe, Mortara Instrument, Milwaukee, WI)对心搏进行分类,比要时进行手动测量并矫正.测量的QT间期及T波振幅等心搏信息以XML格式输出,用COMPAS软件(复极化综合分析软件, University of Rochester Medical Center Rochester, NY)整合。

为确保复极稳定性及增加信号噪声率,我们采用以下方法:Holter记录以10个连续窦性搏动进行分段 为确保复极稳定性及增加信号噪声率,我们采用以下方法:Holter记录以10个连续窦性搏动进行分段. 典型搏动(中位搏动)由搏动所在段之前至少5分钟内心率稳定的10个连续搏动计算而得。心率稳定即先前五分钟内, RR间期的变化小于300ms.如果9个RR间期保持在平均值±10% 范围内,第10次搏动即为稳定。QT间期及T波振幅的测量基于II导稳定的典型搏动。

研究 2 不同心率的QT 间期延长 The RR bin method is inspired from the work of Badilini et al. We developed a slightly different algorithm in which averaged values of QT interval duration and T-wave amplitude are measured from a set of representative beats rather than a unique one for a given RR bin (limited RR-interval range). This ensures that repolarization measurements are based on valid representative beats in case of rapid drug-induced changes in T-wave morphology. We applied the bin technique to characterize the behaviors of the T-wave quantifiers across heart rate. The analysis of QT/RR relationship at baseline in healthy subjects suggested a linear slope equal to 0.12±0.04 in healthy subjects and a significantly higher slope in LQT1 and LQT2 carriers (QT slope >0.17, p<0.05). It is noteworthy that the QT prolongation present in both form of the LQTS is much more prominent in LQT2 patients at low heart rate (RR>1100msec). This stronger prolongation is consistent with the current understanding of the primary role of the Ikr current in the repolarization process at low heart rate. One expect the prolongation to be more important in LQT2 patients at low heart rate if these patients are associated with a reduction of the IKr ion kinetics. Also , the slide illustrates that both groups have QT prolongation and consequently the QT interval is not useful to separate the different types of LQTS mutations (lQT1 vs. LQT2). Baseline vs. 320 mg: p<0.05 for all RR bins; Baseline vs. 160mg: p<0.05 for all RR bins;160 mg vs. 320 mg : p=0.05 for RR≥750 ms

RR bin方法源于 Badilini等人的研究，我们发现了一种略有不同的测量QT间期及T波振幅平均值的算法,该算法测定典型搏动而不是某一特定的RR bin单独搏动. 从而确保复极化基于测定有效的典型搏动,以避免药物快速诱导导致的T波形态改变。 我们应用bin技术描述不同心率的T波形态特征。 健康个体基础状态下QT/RR相关性分析显示健康个体线性斜率为0.12±0.04, 而LQT1及LQT2携带者的斜率明显升高(QT斜率>0.17, p<0.05). 值得注意的是, 慢心率下QT的延长以LQT2更为突出(RR>1100ms). 这种显著延长与目前关于慢心率下复极过程中ikr电流起首要作用的最新认识相一致. 如果某LQT2患者的IKr离子动力下降,则可预测该患者慢心率下QT延长更为明显。 此外，这张幻灯说明了两组均存在QT延长,因此用QT间期区分不同的LQTS突变类型(lQT1 vs. LQT2)意义不大。

T波向量测量, HR相关性与LQTS 突变 研究 2 基础状态 vs. 320mg :所有RR bins显著差别 p<0.05 This slide reports the differences in behaviors of the T-wave amplitude across heart rate between the two mutations and the group of healthy individuals. The RR bin method is used to represent these relationships. The LQT1 and LQT2 patients are characterized by different relationship between T-amplitude and heart rate. LQT2 patients have an impairment of the relationship between the amplitude of the T-wave and the heart rate. This abnormality is not present in healthy individuals or in the LQT1 patients. 基础状态 vs. 320mg :所有RR bins显著差别 p<0.05 基础状态 vs. 160mg :所有RR bins显著差别 p<0.05 160 mg vs. 320 mg: RR≥750 ms时 p=0.05

这张幻灯显示了两突变组与健康人之间在不同心率下T波振幅的差异，RR bin方法表明了它们的相关性 这张幻灯显示了两突变组与健康人之间在不同心率下T波振幅的差异，RR bin方法表明了它们的相关性. LQT1及LQT2的T波振幅与心率的相关性呈不同特征. LQT2的T波振幅同心率不相关，而在健康人及LQT1患者中该相关性尚存。

LQT1及LQT2患者的不同之处 研究 2 模型 敏感度 特异度 确诊LQT2的敏感度和特异度基于最佳的概率值。 Clinical 56% 57% ECG 90% 91% VCG 96% We investigated the interest of the repolarization parameters for classifying the LQTS patients in their own type of mutation (LQT1 vs. LQT2). We have developed 3 multivariate models: 1) A model relying on QT and RR interval only (QT-RR model), a second model based o scalar parameters (QT , RR, T-waves velocity) and 3) a model based on vectocardiographic parameters (+ the parameters from the two previous models). The model selection process was adjusting for the number of selected parameters. Using the morphological parameters, either from the scalar or the vectocardiographic signals, significantly increases the ability of the models to classify patient into the two groups. Using only QT and RR, the sensitivity and specificity are close to 50%, adding the information about the repolarization morphology lead to values close to 95% for both the specificity and the sensitivity. 确诊LQT2的敏感度和特异度基于最佳的概率值。

我们研究复极参数区分LQTS突变类型的意义. 为此开发了了3种多变量模型:1) 模式仅依靠QT及RR间期 (QT-RR 模式), 2) 模式基于向量参数 (QT , RR, T波速度) 3) 模式基于心电向量参数（前两种模式参数的组合)，选择不同模式来调整参数的数目.使用向量或心电向量信号中的形态学参数可显著增加突变类型的区别度，仅使用QT及RR,敏感度及特异度接近50%,而增加复极形态可使敏感性和特异性都接近95%。

结论 LQTS患者的心电图显示了QT间期的延长及异常的T波形态. 计算方法有助于对向量心电图中T波形态定量分析. 研究 1 & 2 结论 LQTS患者的心电图显示了QT间期的延长及异常的T波形态. 计算方法有助于对向量心电图中T波形态定量分析. 我们开发的模式提示T波形态测量可有效确诊LQT2患者并区别LQTS的不同突变类型(LQT1 vs. LQT2). 预初结果尚需独立样本研究资料证实。 In conclusions, we demonstrated that automatic algorithms quantifying T wave morphology applied to digital Holter recordings are very effective in discriminating LQT1 and LQT2 carriers using simple parameters. T-wave morphology is more informative than QT duration when discriminating two LQTS genotypes.

总之，我们发现数字Holter记录中采用简便参数自动量化T波形态, 可有效区分LQT1及LQT2携带者，区分两种LQTS基因型时,T波形态比QT间期更为有效。

复极波形在获得性LQTS中的作用 If the repolarization morphology might be clinically useful in the congenital form of the LQTS. It has not been thoroughly investigated in the acquired form of the LQTS. It is well-accepted that a QTc interval beyond 500 msec is a clear predisposing factor for the occurrence of drug-induced torsades de pointes (TdPs), but the presence of a prolonged QT-interval duration below 500 msec is associated with a less clear-cut risk. The majority of patients with acquired LQTS show QTc<500ms, a value with equivocal diagnostic and prognostics significance. The development of new biomarkers complementing the QT interval measurements for the identification of the IKr-inhibitory effect of drugs is of major interest. The analysis of ECG recordings from the patients with the congenital LQTS suggested that changes in T-wave morphology are associated with ion dysfunctions. Most torsadogenic drugs have been associated with a reduction of the rapid components of the potassium currents of the myocardial cells. Thus, we investigated the role of T-wave morphology in the acquired form of the LQTS.

复极波形可能对先天性LQTS有有效作用,但其在获得性LQTS中的作用并未深入研究。先天性或获得性LQTS中, QTc间期超过500ms作为尖端扭转型室速发生的明确易感因素已被广为接受, QT间期延长小于500ms时室速发生风险相对降低。该临界值对明确诊断诊及预后评估的意义都模棱两可(*). 用以识别先天性LQTS室性心律失常易感性并评价药物对IKr的抑制作用的新的生物标记物的出现,弥补了QT间期测量的不足，引起了人们极大的兴趣。 分析先天性LQTS患者的ECG记录提示，T波形态改变同离子异常有关。大多数致尖端扭转性室速药物与心肌细胞快钾电流减少有关。鉴于此，我们研究T波形态在获得性LQTS中的作用.

引言 由于大多数药物因减弱心肌细胞快钾电流致心脏毒性而已经退出市场。 快速延迟整流钾通道(Ikr)阻滞剂主要延长M细胞的APD,增加心室内电压梯度 (1) 心室复极过程中,快钾电流(IKr)及慢钾电流(IKs) 的心率依赖性作用不同。(2) Most of the drugs remove from the market because of their cardiotoxic effect have been associated with a reduction of the rapid components of the potassium currents of the myocardial cells. Our preliminary work have been to study the effect of IKr blocking compounds on the morphology of the T-wave and on the relationship between the repolarization signal and the heart rate. (1) Antzelevitch C, Shimizu W. Cellular mechanisms underlying the long QT syndrome. Curr.Opin.Cardiol 2002 Jan;17(1):43-51 (2) Jurkiewicz NK, Sanguinetti MC. Rate-dependent prolongation of cardiac action potentials by a methanesulfonanilide class III antiarrhythmic agent. Specific block of rapidly activating delayed rectifier K+ current by dofetilide. Circ.Res. 1993 Jan;72(1):75-83

该预初试验已经研究了IKr阻滞剂对T波 形态及复极信号与心率关系的影响。

研究假设 我们假设快速延迟整流钾电流减少与异常的T波静态及动态特征有关. 基于对IKr阻滞药物的两个回顾性研究,我们研究服用两种药物的健康人的异常心电图特点: 研究 3: 索他洛尔对T波形态的影响 研究 4:莫西沙星是否同T波形态改变有关？ We describe 2 additional studies (study 3 & 4) in which the ECGs from 2 independent groups of healthy individuals exposed to sotalol and moxifloxacin. The study #3 aims at identifying the effect of Ikr inhibition induced by sotalol on the repolarization signal based on Holter recordings whereas the Study #4 assess the presence of morphological changes in ECGs of healthy subjects exposed to moxifloxacin in standard 12-lead ECGs.

在此介绍两个附加研究(研究3 和4), 服用索他洛尔及莫西沙星的两组独立健康人群。研究3的目的是基于Holter记录的复极信号,识别索他洛尔诱导的IKr抑制效应，而研究4则应用标准12导心电图来评价服用莫西沙星的健康人心电图的改变。

索他洛尔研究 辉瑞公司全球研发中心心电图的研究 研究 3 STUDY #3: In the acquired long QT syndrome (LQTS), an inhibition of the rapidly activating delayed rectifier potassium current (IKr) is the main mechanism associated with drug-induced repolarization delay and risk of cardiac arrhythmia known as torsades de pointes. The molecules of these QT-prolonging drug bind to various sites of the KCNH2 (HERG) channels of the myocardial cells and disturb their functional properties. The underlying torsadogenic mechanism observed in drug-induced LQTS is similar to the one reported in patients with the LQT2 syndrome. In this congenital form of the syndrome, the genetic KCNH2 mutation leads to structural ion-channel defects and/or intracellular “trafficking” abnormalities causing a reduction in the number of operational IKr-specific ion channels, thus prolonging the ventricular repolarization process and increasing heterogeneity of repolarization within the ventricles. In this study, we aimed to investigate the static and dynamic aspects of the repolarization morphology inlcuding T-wave amplitude adaptation to changing heart rate during various conditions attributed to sotalol-induced abnormal IKr-kinetics. Sarapa N, Morganroth J, Couderc JP, Francom SF, Darpo B, Fleishaker JC, McEnroe JD, Chen WT, Zareba W, Moss AJ. Electrocardiographic identification of drug-induced QT prolongation: assessment by different recording and measurement methods. Ann.Noninvasive.Electrocardiol. 2004 Jan;9(1):48-57 Couderc JP, Zareba W, Moss AJ, Sarapa N, Morganroth J, Darpo B. Identification of sotalol-induced changes in repolarization with T wave area-based repolarization duration parameters. J Electrocardiol 2003;36 Suppl:115-20. Couderc JP, Vaglio M, Xia X et al. Impaired T-amplitude adaptation to heart rate characterizes Ikr-inhibition in the congenital and acquired forms of the long-QT syndrome. Journal of Cardiovascular Electrophysiology. In press 2007.

研究 #3: 在获得性LQTS中, 对快速活化整流钾通道(IKr)的抑制是药物诱导的复极延迟及致尖端扭转室速发生风险的主要机制。致QT延长药物分子与心肌细胞KCNH2(HERG)通道的不同位点结合,干扰它们的功能。药物诱导的LQTS中所观察到的潜在致尖端扭转室速机制与报道的LQT2综合征相似。先天性LQTS中,KCNH2基因突变导致离子通道结构缺陷和/或细胞内“运输“异常,致功能性 IKr特异离子通道数目减少，进而延长心室复极过程并增加心室复极的不均一性. 本研究中，我们致力于是研究复极波形的静态及动态特征，包括各种条件下索他洛尔诱导IKr动力学异常致心率变化而造成的T波振幅变化。

研究人群 索他洛尔研究 (Betapace®) : 3次24h动态心电图 : 基础状态 单剂量索他洛尔后 (160 mg) 研究 3 研究人群 索他洛尔研究 (Betapace®) : 3次24h动态心电图 : 基础状态 单剂量索他洛尔后 (160 mg) 双倍剂量索他洛尔后 (320 mg) 39名健康志愿者 (11 名女性) 年龄: 18-45 岁 (平均 27 岁) 体重: 47-108 kg (平均 74 kg) BMI: 18.2-30.8 kg/m2 (平均 24.4 kg/m2) 33名白人, 2名黑人, 2人种族不明 The study populations consisted of 37 healthy individuals who participated in a study focused on the effect of sotalol on ECG parameters of repolarization. The healthy individuals were enrolled in the sequential treatment study which included 3 days of Holter recordings: baseline, single 160 mg dose of sotalol and a single 320 mg dose of sotalol. The dosing was done at 8:00AM in the morning during the two exposure days under fasting conditions. The size of the group of healthy subjects was reduced from 37 to 21 in the 320mg sotalol dose arm. All 10 females were excluded because of the large QT prolongation measured at a 160 mg dose.

研究对象由37名健康人组成，目的在于研究索他洛尔对心电图复极参数的影响，研究对象登记入连续治疗研究中，进行3次Holter记录:基础状态,服用索他洛尔160mg时及索他洛尔320mg时，均为早上八点、空腹给药。服用320mg索他洛尔时, 服药人数由37减少到21；其中10名女性服用160mg索他洛尔时，QT间期显著延长而均被排除.

Holter ECG 记录 动态Holter ECGs: 研究3 Holter ECG 记录 动态Holter ECGs: Holter H12记录器提供12导心电图信号 (Mortara Instrument, Milwaukee, WI). 振幅分辨率: 12 bits (6.25 µV) 采样频率: 180Hz 心电图记录时间 : ~24 hours The same ECG recording technology and the same method for analyzing the repolarization was used than in the study #2 (see slide 27) All the Holter ECGs were recorded for 24-hour using the same type of equipment: digital 12-lead Holter recorder H12 (H-12 recorder, Mortara Instrument, Milwaukee, WI) providing digital ECG signal at a sampling frequency of 180 Hz and with 12 bit amplitude resolution. The 8 original leads are recorded and the remaining 4 leads (augmented limb leads aVR, aVL, aVF and lead III) are calculated. Beat classification was performed using the H-Scribe scanning software (HScribe, Mortara Instrument, Milwaukee, WI) and manually reviewed and adjusted when necessary. The information about cardiac beat annotation was exported in XML format and integrated into the COMPAS software (COMPhrensive Analysis of the repolarization Segment software, University of Rochester Medical Center Rochester, NY) for the QT and T-amplitude measurements. To ensure stability of repolarization and increase signal-to-noise ratio, we adopted the following strategy: the Holter recordings were divided in sections of 10 continuous sinus beats. A representative beat (median beat) was computed from the consecutive 10 beats only if the section was preceded by stable heart rate within the previous five minutes. Heart rate stability required having less than 300 ms changes between continuous RR values within these preceding five minutes. Then, the 10-beat section was defined stable if the variation of the nine RR intervals remained into the range of values defined by ±10% of the average RR interval. The QT interval and T-amplitude measurements were based on the “stable representative beats” from lead II. 静态复极间期测量: 基于10次连续搏动的典型搏动 静态 :先前五分钟内的ΔRR<300 ms HR 稳定性 : |ΔRR|<10 % 除外窦外搏动

使用与研究2相同的ECG记录技术及复极分析方法(见幻灯27页)。 使用与研究2相同的ECG记录技术及复极分析方法(见幻灯27页)。 所有Holter心电图均用同类型仪器记录24小时:数字化12导记录器 H12 (H-12 记录器, Mortara Instrument, Milwaukee, WI) 提供180Hz采样频率及12bit振幅分辨率的数字心电图信号。8个原始导联做记录,剩余4导联 (加压肢体导联 aVR, aVL, aVF 及 III导) 做计算. 应用H-Scribe扫描软件(HScribe, Mortara Instrument, Milwaukee, WI)对心搏进行分类,比要时进行手动测量并矫正.测量的QT间期及T波振幅等心搏信息以XML格式输出,用COMPAS软件(复极化综合分析软件, University of Rochester Medical Center Rochester, NY)整合。

为确保复极稳定性及增加信号噪声率,我们采用以下方法:Holter记录以10个连续窦性搏动进行分段 为确保复极稳定性及增加信号噪声率,我们采用以下方法:Holter记录以10个连续窦性搏动进行分段. 典型搏动(中位搏动)由搏动所在段之前至少5分钟内心率稳定的10个连续搏动计算而得。心率稳定即先前五分钟内, RR间期的变化小于300ms.如果9个RR间期保持在平均值±10% 范围内,第10次搏动即为稳定。QT间期及T波振幅的测量基于II导稳定的典型搏动。

结果 RR bin 分析: QT 研究 3 基础状态 vs. 320mg :所有RR bins显著差别 p<0.05 The RR bin method is described in the slide #15. We investigated the repolarization values for heart rate between 86 bpm and 53 bpm using 17 bins (RR varying from 700 to 1125 ms by steps of 25 ms). For each bin, we computed the average values of QT duration and the standard deviation of these measures in each RR bin. The figure illustrates the QT/RR relationship in our study groups and confirms the QT interval prolongation induced by sotalol. 基础状态 vs. 320mg :所有RR bins显著差别 p<0.05 基础状态 vs. 160mg :所有RR bins显著差别 p<0.05 160 mg vs. 320 mg: RR≥750 ms时 p=0.05

RR bin 方法在幻灯30#中描述过. 采用17bin(RR从700ms开始25ms速度递增到1125ms)法研究心率在86次/分至53次/分范围内的复极化指标。计算每次RR bin的QT间期的平均值及标准差，此图说明了该研究人群中QT/RR的关系,并证实索他洛尔诱导QT间期的延长.

结果 获得性LQTS的心电图特征 非药物组 n=37 低剂量组 n=37 高剂量组 n=21 RR (ms) 784±72 893±63† 研究 3 结果 获得性LQTS的心电图特征 非药物组 n=37 低剂量组 n=37 高剂量组 n=21 RR (ms) 784±72 893±63† 947±70†* T-振幅 (mV) 041±0.15 0.41±0.15 0.36±0.12 QT (ms) 367±19 405±23† 427±24†* QTc F (ms) 399±16 422±22† 437±20†* QTc B (ms) 417±18 431±24† 441±20† This tables summarizes the results we obtained when computing the QT interval duration based on classic heart rate correction formulae (Bazett and Fridericia). As expected sotalol is associated with dose-dependent effect on the QT interval with an average prolongation of 20 msec at 160 mg and 40 msec at 320 mg. QTc B: Bazett’s 公式校正的QT QTc F: Fridericia’s公式校正的QT †: p < 0.01 与未用药相比. * p<0.05 与低剂量组相比

此表总结了根据校正公式(Bazett 和Fridericia)计算得出的QT间期，索他洛尔与QT间期延长呈剂量相关性:160mg时平均延长20ms,而320mg时平均延长40ms.

结果 RR bin 分析: T 波振幅 研究 3 基础状态 vs. 320mg :所有RR bins显著差别 p<0.05 The values of T-wave amplitude are shown across the RR bins for the three days of the experiment. The effect of sotalol on T-wave amplitude shows very abnormal pattern with a clear dose-dependent effect of the drug on T-wave amplitude that is exacerbated at low heart rate. The same phenomenon was observed in LQT2 patients (study #2). 基础状态 vs. 320mg :所有RR bins显著差别 p<0.05 基础状态 vs. 160mg :RR≥975 ms时 p<0.05 160 mg vs. 320 mg: RR≥1000 ms时p=0.06

结果显示了三次holter中不同RR bin时的T波振幅值，索他洛尔对T波振幅的影响呈现异常的剂量相关性，心率慢时影响加剧。 LQT2患者中也有相似现象 (研究 #2).

研究 3 结果 T波振幅减小: ECG 模式 This slide illustrates the impairment of T-amplitude following sotalol. On the right panel, 3 cardiac beats are superimposed and were recorded at 3 heart rate (RR=800, 9000,1000 msec). On the left panel, cardiac beats from the same individual after 320 mg of sotalol for similar heart rate. The T-wave configurations are very different with an amplitude of the T-wave that does not depend on the heart rate on sotalol. The analysis of the T-wave across heart rate reveals a profound modification of the repolarization process. This changes is more pronounced at slow heart rate when the role of the Ikr kinetic is playing a prominent role in the repolarization of the myocardial cells.

此幻灯解释了应用索他洛尔后T波振幅减小. 右图中，三种不同心率(RR=800, 9000,1000 ms)的心搏重叠，左图中,同一个体服用320mg索他洛尔后相同心率的心搏。T波形态与T波振幅对索他洛尔的反应有所不同，后者与心率无关,心率相关性T波形态的分析是对复极过程的深入揭示。如果心肌细胞复极过程中IKr动力学发挥重要作用,则T波形态改变在心率慢时更为突出.

结果 T波振幅减小与 Ikr-相关异常 健康组 N=37 LQT1 N=49 LQT2 N=25 低剂量 Sotalol 高剂量 N=21 研究2和3 结果 T波振幅减小与 Ikr-相关异常 健康组 N=37 LQT1 N=49 LQT2 N=25 低剂量 Sotalol 高剂量 N=21 QT/RR 斜率 (n.u.) 0.12±0.04 0.17±0.10* 0.22±0.16* 0.15±0.05* 0.14±0.06 Tamp/RR斜率(µV/ms) 0.55±0.29 0.62±0.40 0.31±0.27*‡ 0.26±0.19*‡ 0.21±0.14*‡ We merged our results from study #2 and study #3 . As reminder, all individuals and patients were recorded with the same Holter technology. We report the slope of T-amplitude/RR and QT/RR relationship for the groups of Healthy individuals at baseline and at low (160 mg) and at high dose (320 mg) of sotalol. The values for the populations of patients with genotyped LQT1 and LQT2 mutation are included in this table. The results reveals that the groups of individual with IKr blockade have a significant decrease of the value describing the relationship between the amplitude of the T-wave and the RR intervals. The patients with LQT1 mutation have a T-amplitude /RR profile similar to healthy individuals. And QT/RR slope is significantly higher than normal individuals for the groups of patients with the congenital LQTS. *与健康人相比p<0.05, ‡与LQT1相比 p<0.05.

研究2及3的合并结果 ：值得注意的是, 所有个体及患者采用相同的Holter技术来记录. 研究报道了健康人在基线、服用低剂量(160mg)及高剂量(320mg)索他洛尔时的的T波振幅/RR斜率及QT/RR相关性。表中包括了LQT1及LQT2突变基因型患者. 结果揭示服用IKr阻滞剂的个体T波振幅同RR间期的相关系数明显减小。LQT1突变患者同健康人的T波振幅/RR间期关系曲线相似，先天性LQTS患者QT/RR斜率显著高于健康人。

结果 一般线性混合模型: 预测索他洛尔服用情况 研究 2 & 3 结果 一般线性混合模型: 预测索他洛尔服用情况 OR 95% CI p-value QTc (1 msec inc.) 1.05 1.02-1.09 0.004 QT/RR斜率 (0.01 unit inc.) 1.16 0.98-1.10 NS Tamp/RR 斜率 (10µV/msec inc.) 0.54 0.36-0.82 0.005 Linear mixed models were used to compare the ability of the QT/RR and Tamp/RR slopes to predict the presence of Ikr blockade in healthy individuals. The models revealed that Tamp/RR slopes was statistically associated with 46% increased chance to have mutation for each 10microV/msec decrease in value (p=0.005). QT/RR slope was not statistically significant. OR: 比数比, CI: 可信区间. 校正年龄和性别. 61

应用线性混合模型比较健康个体中QT/RR 和Tamp/RR斜率对于Ikr 阻滞的预测价值 应用线性混合模型比较健康个体中QT/RR 和Tamp/RR斜率对于Ikr 阻滞的预测价值.发现Tamp/RR斜率每下降10microV/ms , LQTS突变几率增加46%. 而QT/RR斜率则无统计学差异.

----基于美国FDA心电图数据库资料的初步研究 研究 4 莫西沙星研究 ----基于美国FDA心电图数据库资料的初步研究 STUDY #4: This cardiac safety assessment of new drugs relies on results from a clinical trial specifically designed for identifying small drug-induced QT prolongation from surface ECGs in healthy individuals: the so-called “thorough QT studies” (tQTs). Uniquely relying on the measurements of QT prolongation, these clinical trials generally follow a placebo-controlled cross-over design. They include a positive control group used to validate the QT interval measurement method (no specific QT measurement technique is recommended). The positive control group consists of healthy individuals on moxifloxacin. Moxifloxacin is a drug from the class of fluoroquinolone antibiotics and it is associated with a small repolarization delay (around 5 msec). In a general population, a normal dosage (400 mg) of moxifloxacin is considered a safe compound with a very low rate of torsades de pointes (TdPs). The QT prolongation effect of moxifloxacin is linked to a reduction of the outward rapid component of the delayed rectifier potassium current of the myocardial cells (IKr). Almost all drugs that have been associated with TdPs modify the kinetics of this specific ion current. However, while several drugs that have no history of cardiac events will prolong the QT interval, others will be associated with very small prolongation and torsadogenic properties. Thus, it is recognized that the risk of TdPs is not a function of the QT interval, nor of the extent of the QT-interval prolongation during drug therapy. Consequently, the FDA faces a challenging issue related to the validity of using QT interval measurements for evaluating the safety-level of new drugs, and the Agency recognizes the need for more precise and more meaningful electrocardiographic markers. In this study, we designed and investigated a set of new ECG parameters to specifically quantify delay within the ventricular repolarization process measured on the surface ECGs, but independent from the location of the end of the T-wave. We used a technique based on the principal component analysis of the repolarization signals, and we measured specific intervals in the vectorial repolarization loop. We compared the ability of these new parameters to identify the presence of moxifloxacin in healthy individuals and their precision in comparison to the semi-automatic QT interval measurement. Couderc JP, McNitt S, Hyrien O et al. Electrocardiographic Abnormalities of Repolarization Induced by Moxifloxacin: Improving the Detection of Subtle IKr-Inhibition. Drug Safety J. In press 2007 Couderc JP, Vaglio M, Xia X, McNitt S, Hyrien O. Electrocardiographic Method for Identifying Drug-induced Repolarization Abnormalities Associated with a Reduction of the Rapidly Activating Delayed Rectifier Potassium Current. IEEE Engineering in Medicine and Biology Society, New-York 2006 p. 4010-5. 63

研究 #4: 该新药的心脏安全性评价基于一项特定的健康人临床试验，通过体表心电图识别药物诱发的微小QT间期延长：所谓的“完全的QT研究”。为保证QT延长测量的特异性，这些临床试验一般遵从安慰剂对照的交叉设计。包括一个阳性对照组以保证QT间期测量方法的有效性（缺乏特异的QT测量技术时可资借鉴）。阳性对照组由服用莫西沙星的健康人组成。莫西沙星是一种氟喹诺酮类抗生素，能够轻度延长复极（5ms左右）。一般人群中，正常剂量的莫西沙星（400mg）致尖端扭转性室速（Tdp）发生率非常低，被认为是安全的。莫西沙星延长QT的作用与减弱心肌细胞快速外向延迟整流钾电流(Ikr) 有关。

几乎所有的致TdPs药物都可使该特定离子流的动力学发生改变。一些无心脏不良事件的药物也可延长QT间期，另一些药物只具有轻度延长QT以及诱发尖端扭转室速的特性。因此，Tdps的发生危险并非与QT间期有关，与药物治疗期间QT间期延长程度也无关。于是,FDA应用QT间期来评价药物的安全性，其有效性面临挑战，当局认识到需要更精确，更有意义的电生理指标。 该研究中，我们设计了一系列新的，不依赖于T波终点的心电图参数用以量化心室复极延迟的程度。我们应用基于复极信号的基本成分的分析技术，还测量了心室复极向量环的特定延长。我们比较了这些新参数对莫西沙星使健康人QT间期延长的识别作用，以及其与半自动QT间期测量相比的精确度。

研究人群 平行设计: 40 例, 女性18 例. 随机、安慰剂对照研究. 400 mg 莫西沙星. 研究 4 研究人群 平行设计: 40 例, 女性18 例. 随机、安慰剂对照研究. 400 mg 莫西沙星. 160 例数字化 XML-FDA 标准12导联ECGs,取自 FDA数据库. Forty subjects were enrolled in a randomized placebo controlled design protocol including a baseline, a placebo and a moxifloxacin arm. This retrospective study relies on ECG tracings from 40 individuals recorded during a thorough QT study (tQTs). The recordings were extracted from the ECG FDA Data Warehouse. The tQTs was a parallel, placebo-controlled study including 18 females. The study design excluded individuals with a history of cardiovascular diseases, diabetic patients, individuals with a baseline QTc interval superior to 470 msec and pregnant women. Inclusion criteria also required normal value ranges for body mass index, laboratory screening, and ECG tracings. From the Agency, we obtained four digital ECG recordings per individual acquired over two days. Each day, the two ECGs were recorded at 7:00AM and 9:00AM. Day one was a baseline day. During day two, the individuals received a single dose of 400mg of moxifloxacin (n=20) or a placebo (n=20) according to the arm in which they were enrolled. The moxifloxacin dose and the placebo were given just after the first ECG on day two. The 2nd ECG on day two was recorded 2 hours after dosing at the expected time of maximum concentration of moxifloxacin (9:00AM). One hundred and sixty ECGs from the baseline, placebo and moxifloxacin arms were analyzed. 66

40名个体纳入一项随机安慰剂对照试验，包括基线水平、安慰剂和莫西沙星组。 该回顾性研究基于一项完全QT研究(tQTs)中描记的40例个体的心电图。记录取自FDA心电图数据库。(tQTs)是一项平行的，安慰剂对照研究，包括18名女性。研究排除了有心血管，糖尿病病史，基线QTc超过470ms以及妊娠的个体。入选标准还包括体重指数、实验室检查、心电图正常。 研究中，每位个体分别于两天的7:00AM和9:00AM记录数字化心电图（共4份），第一天为基线日，第二天，根据入组情况接受单剂量400毫克的莫西沙星(n=20)或安慰剂(n=20)。莫西沙星和安慰剂在第二天开始时服用。第二天的第二份心电图在预计莫西沙星血药浓度高峰时记录，即用药后2小时(9:00AM)。分析了基线、安慰剂和莫西沙星组的心电图160份。

研究 4 复极参数 The measurements of the RR intervals and repolarization intervals were based on technology developed at the University of Rochester Medical Center, NY. The COMPAS software provided the identification of the end of the T-wave on lead II based on a technique identifying the crossing-point between the baseline and the descending slope of the T-wave (least-squares technique). The end of the T-wave was visually checked by trained technicians and manually adjusted using the COMPAS on-screen caliper if the automatic algorithm failed to correctly identify the end of the T-wave (semi-automatic method). All measurements and the manual adjustment of the QT interval durations were done in a blindly fashion. The QT interval measurements were done in all available sinus beats of lead II and the median value was reported. The apex of the T-wave relied on a method using a parabola fit of the T-wave where the maximum of the parabola identified the location of the apex. The TpTe intervals was computed from QT and QT apex intervals such as TpTe=QT-QTapex. Baseline wandering was adjusted using Spline interpolation. The amplitude of the T-wave was measured at the apex of the T-wave. The right (αR) and left (αL) slopes of the T-wave, expressed in µV/msec, were computed using least-square regression method fitting the up and down slopes of the T-wave (see slide #11). Vectocardiographic Measurements The vectorcardiographic measurements were based on the principal component analysis (PCA) of the repolarization segment defined between the J point and the point located 220 ms before the next R peak. This ensures that 1) the analysis encompasses all components of the ventricular repolarization signal and 2) it is independent from the determination of the end of the T-wave. Such method requires the individuals or patients to be at rest. Briefly, it uses the representation of the repolarization signal in a plane defined by the two first eigenvectors of the PCA, the so-called “preferential plane of the T-loop” (lower panel on the slide). Based on an amplitude threshold depending on the normalized value of the maximum vector of the loop, we define a set of interval durations depending on the morphology of the T-loop. The duration of these intervals are defined by amplitude thresholds equal to 30%, and 70 % of the maximum vector amplitude of repolarization. These thresholds were selected a-priori to have measurements progressively encompassing the overall vectocardiographic loop. The measurements prior to occurrence of the maximum vector are called early repolarization duration (ERD), whereas the ones after this point are called late repolarization duration (LRD). The total repolarization duration (TRD) is the sum of ERD and LRD. In addition, we report the repolarization complexity of the loop corresponding to the ratio of the two first eigenvalues. 68

测量RR间期和复极间期的技术由纽约Rochester大学医学中心开发。应用COMPAS软件鉴别II 导联上T波的终点，基线和T波降支交点的识别基于最小二乘法技术。如果自动算法不能正确地识别T波终点（半自动方法），则应用跟踪技术和COMPAS屏幕分规手动调节测定。全部的QT间期测量和手动修正均在盲法下进行。测量全部的II 导联有效窦性QT间期并报告中位数。T波顶点通过抛物线适应的方法确定为抛物线的最大值。TpTe 间期通过QT和 QT 顶点计算如下：TpTe=QT-QTapex. 基线漂移通过样条内插法修正。T波的幅度在T波顶点处测量。 T波的右(αR)和左(αL)斜率用µV/msec来表述，最小二乘回归法计算T波的升降支斜率（见幻灯片#20）。

心电向量测量 心电向量的测量基于复极段的基本成分分析(PCA)，其中复极段定义为J点至下一个R峰前220毫秒的区间。这就保证了1）分析涵盖了心室复极信号的全部成分，2）不依赖于T波终点的识别。该方法需要个体或患者处于休息状态下。简而言之，应用PCA初始的两个矢量所决定定义平面的作为代表， 即所谓的“T环优先平面”。基于由环最大向量正常值决定的幅度阈值，我们定义了一系列T环形态学的间期参数。这些间期定义为复极最大向量的30%和70%的幅度阈值。首选这些阈值渐进测量整个心电向量环。 最大向量发生前的测量成为早期复极(ERD)，而该点后被称为晚期复极(LRD)。完整复极间期是二者之和(TRD)。此外，我们报道了与两个最早特定值相对应的复极环复杂性。

Median difference vs. placebo Study 4 集中趋势分析 Median difference vs. placebo 95% CI p lower Upper T magnitude (mV) -0.03 -0.05 0.00 0.08 QT offset (msec) 10 1.1 26.9 0.04 αL (µV/ms) -0.3 -0.65 -0.07 0.03 αR (µV/ms) 0.4 1.08 0.06 TpTe (msec) -6.7 4.7 0.41 λ 2/ λ 1 -0.1 0.1 ERD30% (msec) 14 3.8 18.4 0.01 This table contains the means and standard deviations of moxifloxacin-induced changes (adjusted for placebo effect) values in the placebo and moxifloxacin arms. The mean of QTc apex, QTc/QTcF, αL, and ERD30% were found statistically significantly different between the placebo group and the moxifloxacin group (p<0.05). The differences for the amplitude of T-wave and for αR were close to being significant (p≤0.08). Our analysis did not reveal any significant changes due to moxifloxacin in the TpTe interval, the repolarization complexity (λ2/λ1). The results shows that changes of repolarization segment on the surface ECG induced by moxifloxacin (and controlled for the placebo-effect) are affecting primarily the T-wave prior to the apex: αL is associated with a loss of -0.3 µV/ms (p=0.03) and ERD30% is prolonged by 7 msec (p=0.01). Interestingly, this finding is supported by the values of Δmoxi-baseline for QTc apex and ERD30%, which are prolonged by 4 msec. The repolarization signal following the apex of the T-wave is not significantly affected by the drug, while TpTe interval. The average decrease in αR does not reach the level of significance, and mainly reflects the changes in T-wave amplitude because the TpTe interval is not modified. The vectocardiographic parameters did not show evidence of increased heterogeneity of repolarization in the complexicity (λ2/λ1) or the planarity (λ3) of the repolarization during drug therapy. Their p-values were equal to 0.9. 所有测量结果通过新绿混合公式进行校正 71

该表包括莫西沙星所致变化的均数和标准差值（校正安慰剂效应）。安慰机组和莫西沙星组的平均QTc峰值、 QTc/QTcF, αL, 以及 ERD30%存在显著的统计学差异(p<0.05)。 T波幅度和αR的差异接近于有统计学意义(p≤0.08)。分析未发现莫西沙星引起的TpTe间期和复极复杂性有显著性改变。 结果显示由莫西沙星应起的体表心电图复极段改变主要影响在T波顶点前： αL 减少了0.3 µV/ms (p=0.03)，ERD30% 延长了7 ms (p=0.01). 值得注意的是，莫西沙星基线QTc峰值和ERD30%变量延长了4毫秒，从而也支持该结论。T波后的复极信号未受药物的显著影响， αR的平均减少至未达到统计学差异，主要反映了T波幅度的改变，因为 TpTe 间期没有变化。 心电向量参数没有显示药物治疗期间复极复杂性(λ2/λ1)或复极平面(λ3)中复极异质性的升高。p值等于0.9。

莫西沙星引起的复极化异常 Study 4 Simulated ECG tracings Two superimposed simulated ECG signals based on the values and drug-induced changes of the repolarization parameters, reported in the previous slide, are shown. The ECG tracings with the shorter QT interval is constructed based on the baseline values (QT apex, QT, αR. αL and T amplitude), and it represents the averaged T-wave morphology in healthy individuals. The dotted tracing is constructed based on the  values of these parameters reported. We observed that TpTe interval was not changed by moxifloxacin (QTapex=QT), but the downslope of the T-wave was decreased, leading to morphological changes in the second part of the T-wave. The moxifloxacin-induced delay of repolarization is concentrated in the interval just prior to the apex of the T-wave where the slope of the T-wave is most changed by both the decrease of T-wave amplitude and slow movement of the repolarization front. Simulated ECG tracings 73

前面报告过基于药物引起复极参数变化的两个叠加的心电图模拟信号已在。心电图描记的较短的QT间期缩短源于基线值（QT顶点, QT, αR 前面报告过基于药物引起复极参数变化的两个叠加的心电图模拟信号已在。心电图描记的较短的QT间期缩短源于基线值（QT顶点, QT, αR. αL和 T波幅度），代表了健康人的T波形态。散点描记基于这些参数的D值。我们观察到莫西沙星不会使TpTe间期改变(DQTapex=DQT)，但是T波的降支下降，导致T波第二部分的形态改变。莫西沙星引起的复极延迟集中于T波顶点前的间期，T波斜率由于T波幅度和复极相对的缓慢移动而改变。

莫西沙星抑制Ikr 与体表心电图复极异常 多变量分析 研究 4 莫西沙星抑制Ikr 与体表心电图复极异常 多变量分析 The ROC curves computed from three binary logistic models were used to classify the ECGs from individuals on moxifloxacin or placebo. The QTc model is based on QTc interval only. The morphological model (morphology) relies on TRD30%, ERD30%, and αR whereas the hybrid model combines the morphological model with scalar parameters namely QT apex and TpTe intervals. The Area under the curve (AUC) of the morphological and hybrid models were significantly different (p=0.008). The arrows indicate the location of the points where the sum of sensitivity and specificity are maximized for each model. The model relying on morphological parameters outperformed the QTc model for detecting the ECGs of individual on moxifloxacin. 75

通过3个二元逻辑模型计算得到的ROC曲线区分莫西沙星或安慰极。QTc模型仅基于QTc间期。形态学模型依赖于TRD30%, ERD30%, 和αR，而混合模型由形态学模型和数量参数，即QT峰值和TpTe间期组成。形态学和混合模型曲线下的面积显著不同(p=0.008)。箭头指示了每种模型的敏感性和特异性之和的位置。 该模型依赖于莫西沙星治疗个体的心电图QTc模型计算出的形态学参数。

稳定性和重复性 短期 长期 研究 4 QTc apex (msec) QTc (msec) TpTe (msec) repolarization parameters 短期 长期 IrPV IaPV Rep. (%) QTc apex (msec) 17.9 10.0 76 17.0 12.1 67 QTc (msec) 12.0 68 20.7 26 TpTe (msec) 9.5 50 7.0 14.8 18 LRD30% (msec) 4.9 4.0 60 5.4 64 ERD30% (msec) 10.5 5.6 77 7.3 8.4 43 T amplitude (mV) 0.05 0.03 74 0.04 63 αL (µV/ms) 0.52 0.35 69 0.46 0.41 55 αR (µV/ms) 0.87 0.58 0.71 0.62 57 Complexity (λ 2/ λ 1) 0.07 14 0.06 Planarity (λ3) 0.01 0.02 33 82 This slide reports the values of intra/inter-patient variability (IaPV/IrPV) and reproducibility of repolarization parameters. We investigated short- (between hours same day) and long-term (between days same hour) variability and reproducibility of the repolarization parameters. We compared baseline measurements done within the same day and measurements from ECGs recorded at day one versus day two. The ERD30% and QT apex parameters have an excellent short-term reproducibility with values of 0.77 and 0.76, respectively. QT, TpTe, LRD, T amplitude, αR and αL slopes have good short-term reproducibility with reproducibility values ranging from 0.50 to 0.74. The complexity and planarity of the repolarization loop were associated with the lowest reproducibility values (0.14 and 0.33, respectively) revealing their poor short-term reproducibility. The IaPV and IrPV should not be compared between parameters since they have either different units or scales. When comparing intra- to inter-patients short-term variability by parameters, all the parameters have lower IaPV than IrPV (ERD30%: IaPV=5.6 msec, IrPV=10.5 msec; QT apex: IaPV=10.0 msec, IrPV=17.9 msec; QT: IaPV=12.0 msec, IrPV=17.0 msec) but the complexicity (IaPV=0.07, IrPV=0.03 msec) and the planarity parameters (IaPV=0.02, IrPV=0.01 msec). The long-term variability and reproducibility of the parameters were different from the short-term ones. In average amongst all investigated repolarization parameters, the short-term reproducibility is slightly higher than the long-term (59% vs. 53%). More interestingly the QT and TpTe intervals reveal poor long-term reproducibility mainly driven by larger intra-patient variability. There were significantly different changes in heart rate between the two sets of ECGs considered for long-term sensitivity analysis (moxifloxacin vs. placebo arms): 21±140 vs. 178±148 msec, p=0.007. Whereas for the short term variability, the difference in heart rate changes were: -124±140 vs. -31±160 msec (p=0.14). After correction for heart rate, none of the repolarization parameters used in our models showed significant changes between baseline periods. Nevertheless, one would note that Bazet’s and Fridericia’s formulae have correction errors depend on heart rate values and thus comparing groups with very different heart rate might affect the stability of a corrected parameter. The ERD30% and LRD30% parameters show also lower long-term reproducibility, but they remain in a good range (>40%). IrPV: Inter-patient variability IaPV: Intra-patient variability Rep.: Reproducibility based on ICC value. Values in bold highlights the repolarization parameters with poor level of reproducibility (<40%) 77

这张幻灯片显示了患者自身和患者间的变异性(IaPV/IrPV)以及复极参数的重复性。我们调查了短期（同一天不同小时）和长期（同一小时不同日期）的变异性，以及复极参数的重复性。我们比较了同一天内的基线测量和第一天与第二天的心电图测量记录。ERD30%和QT短期重复性好，分别为0.77和0.76, QT, TpTe, LRD, T 波幅度, αR和αL 斜率的短期重复性好，重复率范围从0.50到0.74。复极环的复杂性和平面值的重复率最低，显示其短期重复性差。 由于IaPV和IrPV的单位或测量不同，不应进行参数间的比较。当比较患者中和患者间短期变量时，所有参数的IaPV 低于IrPV (ERD30%: IaPV=5.6 msec, IrPV=10.5 msec; QT apex: IaPV=10.0 msec, IrPV=17.9 msec; QT: IaPV=12.0 msec, IrPV=17.0 msec)，但是复杂性 (IaPV=0.07, IrPV=0.03 msec)和平面参数(IaPV=0.02, IrPV=0.01 msec)相反。

参数的长期变异性和重复性与短期不同。一般而言，几乎所有被研究的复极参数中，短期重复性轻微高于长期重复性(59% vs 参数的长期变异性和重复性与短期不同。一般而言，几乎所有被研究的复极参数中，短期重复性轻微高于长期重复性(59% vs. 53%)。更值得注意的是，由于患者间变异性大，QT和TpTe间期的长期重复性低。在长期敏感性方面，莫西沙星组和安慰剂两组间的心率改变十分显著（ 21±140 vs. 178±148 ms, p=0.007). 而在短期变异性方面，心率改变无显著差别(-124±140 vs. -31±160 ms ,p=0.14)。校正心率后，模型中的全部基线复极参数都没有显著改变。但是，应该注意到Bazet’s和Fridericia’s公式已经校正了心率相关的变量值，因而应用不同的心率进行组间比较可能会影响校正后参数的稳定性。参数ERD30%和LRD30%的长期重复性也较低，但仍在一个好的范围内（〉40%）。

结论 具有IKr 离子流抑制效应的莫西沙星和索他洛尔能显著改变静息和动态复极形态。 计算机化的心电图技术可以量化复极段的形态学改变。 研究 3 & 4 结论 具有IKr 离子流抑制效应的莫西沙星和索他洛尔能显著改变静息和动态复极形态。 计算机化的心电图技术可以量化复极段的形态学改变。 上述预初研究中，新参数比 QTc间期更好的反映了药物抑制Ikr所致的T波形态变化。 80

研究 5:有尖端扭转性室速病史的患者存在特异的复极异常吗? 复极形态异常和尖端扭转性室速有关吗? 研究 5:有尖端扭转性室速病史的患者存在特异的复极异常吗? STUDY #5: Improving the assessment of drug cardiotoxicity, specifically on toxic effects linked to the ventricular repolarization process could depend on the development of better electrocardiographic markers than simply prolongation of the QT interval. The triggering mechanism(s) of drug-induced TdPs remain to be elucidated, and there are several interesting concepts currently proposed: Hondeghem et al. suggested the TRiaD concept emphasizing the role of action potential triangulation, reverse use dependence of the drug and repolarization instability(*). The triangulation of the action potential and the heterogeneity of electrical properties of the cells across the myocardium implicitly lead to an important proarrhythmic factor described by Antzelevitch et al. (**): the transmural dispersion of repolarization (TDR). Meanwhile, ion dysfunction has been associated with specific morphological changes of the T-wave shape on the surface ECGs (see study #1 to #4). Consequently, we hypothesize that the patients with a history of drug-induced TdPs may have a certain level of repolarization impairment (heterogeneity, action potential triangulation, reduced repolarization reserve) that may be reflected on the surface ECG by specific morphological features of their T-waves. These individuals may also present specific changes of T-wave when exposed to torsadogenic drugs such as sotalol. (*) Hondeghem LM, Carlsson L, Duker G. Instability and triangulation of the action potential predict serious proarrhythmia, but action potential duration prolongation is antiarrhythmic. Circulation 2001 Apr 17;103(15):2004-13. (**) Belardinelli L, Antzelevitch C, Vos MA. Assessing predictors of drug-induced torsade de pointes. Trends Pharmacol Sci 2003 Dec;24(12):619-25. Couderc JP, Kaab, S Hionterseer M et al.: Baseline Values and Drug-induced Changes of the Ventricular Repolarization Morphology in the Electrocardiograms of Patients with a History of Drug-induced Torsades de Pointes. Circulation (supplement), 2007, (in press) 81

研究 #5: 提高药物心脏毒性的评价，特别是与心室复极过程有关的毒性效应，要依赖于开发比简单的QT间期延长更好的心电生理参数。药物诱发TdPs的触发机制仍有待阐明，有几个有趣的概念：Hondeghem等提出的TRiaD概念强调了动作电位形态三角形化的作用，药物的反作用依赖和复极不稳定性。Antzelevitch等描述：动作电位形态三角形化和跨心肌层细胞电特性的异质性有潜在性的重要致心律失常作用，即跨二尖瓣的复极离散度 (TDR)。

同时，离子流功能异常已经与体表心电图T波形状的特异性形态学改变联系起来(见研究#1 to #4)。因此我们假设具有药物诱发TdPs病史的患者可能有某种程度的复极功能减低（异质性、动作电位形态三角形化，复极储备下降），这些异常可以通过体表心电图的特异性T波形态特征反映出来。当接受致TdP的药物,如索他洛尔时，这些个体可能表现出T波形态的特异性改变。 (*) Hondeghem LM, Carlsson L, Duker G. Instability and triangulation of the action potential predict serious proarrhythmia, but action potential duration prolongation is antiarrhythmic. Circulation 2001 Apr 17;103(15):2004-13. (**) Belardinelli L, Antzelevitch C, Vos MA. Assessing predictors of drug-induced torsade de pointes. Trends Pharmacol Sci 2003 Dec;24(12):619-25.

研究5 研究人群I 入选在慕尼黑大学医院住院，应用过具有QT延长作用的药物并记录到TdPs的患者。A组(N=17)个体配比掉年龄和性别因素后作为参照组。 所有患者均接受基因检查，通过标准基因技术(从淋巴细胞中制备基因组DNA, 应用多聚酶链式反应扩增KCNQ1, KCNH2, KCNE1, KCNE2 和 SCN5A 随后进行这些主要LQT-疾病基因的直接测序)发现主要LQTS基因的突变。 In this study, the patients were enrolled after being admitted to the University Hospital, Munich for documented TdPs in the context of a drug with QT-prolonging potential. The drugs involved in the triggering TdPs were: sotalol, sumatriptan, amiodarone, bisacodyl, cipramil, furosemide, clarithromycin, erythromycin, roxythromicin. The patients were enrolled for an evaluation of the individual level of repolarization reserve, all patients have signed informed consent to receive doses of sotalol as described in (*). They were all genetically tested for presence of mutation of the major LQTS genes using standard genotyping techniques (genomic DNA was prepared from lymphocytes, amplification of KCNQ1, KCNH2, KCNE1, KCNE2 and SCN5A using polymerase chain reactions were performed, followed by direct sequencing of these major LQT-disease genes). The control group consisted in patients who were started on sotalol for prevention of paroxysmal atrial fibrillation and had given informed consent to enter the study. (*) Kaab S, Hinterseer M, Nabauer M, Steinbeck G. Sotalol testing unmasks altered repolarization in patients with suspected acquired long-QT-syndrome--a case-control pilot study using i.v. sotalol. Eur Heart J 2003 Apr;24(7):649-57. 84

该研究入选在慕尼黑大学医院住院，应用过具有QT延长作用的药物并记录到TdPs的患者。这些触发TdPs的药物有：索他洛尔，舒马曲坦，胺碘酮，双醋苯啶，喜普妙，呋塞米，克拉霉素，乙琥红霉素，罗红霉素。入选这些患者以评价个体复极储备水平，所有患者都签署了知情同意书,服用(*)所述剂量索他洛尔。所有患者均接受基因检查，通过标准基因技术(从淋巴细胞中制备基因组DNA, 应用多聚酶链式反应扩增KCNQ1, KCNH2, KCNE1, KCNE2 和 SCN5A 随后进行这些主要LQT-疾病基因的直接测序)发现主要LQTS基因的突变。对照组由应用索他洛尔预防阵发性房颤，并签署知情同意书的患者组成。 (*) Kaab S, Hinterseer M, Nabauer M, Steinbeck G. Sotalol testing unmasks altered repolarization in patients with suspected acquired long-QT-syndrome--a case-control pilot study using i.v. sotalol. Eur Heart J 2003 Apr;24(7):649-57.

结果 研究 5 This Table provides the average values and standard deviation for most investigated parameters for the baseline values (left columns) and for the individual changes between baseline and sotalol (right columns) for the two groups: individuals with and without history of TdPs. PR and QRS duration were not significantly different between groups at baseline and after drug. All repolarization measurements were heart rate corrected based on linear pooled-formula. The RR intervals are significantly longer after sotalol (+TdPs: 175±98 msec and –TdPs: 201±101 msec, p<0.05), but the bradycardic effect of the drug is not different between groups (p=0.34). Based on the scalar QT interval measurements, we found similar results using the semi-or fully-computerized method in baseline conditions. Sotalol is associated with strong prolongation of the QT interval duration, and this is true for the two groups (+TdPs: 101±45 and –TdPs: 80±48 msec). These changes are statistically different from zero (p<0.0001) but they were not statistically different between groups (p=0.22). The sotalol-induced QT prolongation was 19-msec shorter when using the computerized-method but this difference did not reach statistical significance (+TdPs: 101±45 and –TdPs: 82±54 msec, p=0.28). There was a significantly longer prolongation within the two groups for QT, QT apex intervals (p<0.01). The prolongation was close to statistical significance in the group of individual with a history of TdPs (p<0.06) confirming the results from Kaab et al. based on maximum QT interval from all available leads. More interestingly, sotalol significantly prolongs the TpTe interval only in the group with a history of TdPs (36±41 vs. 6±20 msec, p=0.01). The measurements of the early and late part of the repolarization interval (ERD and LRD) confirm the observations based on QT, QT apex and TpTe intervals. The sotalol-induced delay of the repolarization is increased in both groups but only the late part of the repolarization process (LRD70%) is significantly longer in the ECGs of individuals with a history of TdPs (27±30 vs. 8±13 msec, p=0.03). On average, the QT interval measurement is 25 msec longer in the (+)TdPs group (p=0.06). According to the vectorial parameters, this prolongation is localized within the early part of the repolarization segment as shown by ERD30% and ERD50%. ERD30% is 9 msec longer in the +TdPs group (p=0.02) and this prolongation reaches 14 msec with ERD50% (p=0.03). Interestingly, this delay in the early phase of the repolarization segment is not captured by the QT apex interval revealing that the morphology of the T-wave primarily drives the measurement of this delay. 86

这张表格提供了大多数调查参数的均值和标准差的基线数值（左侧栏）以及基线和索他洛尔组（右侧栏）间的个体差异：有或无TdPs病史。用药前后基线水平的PR和QRS间期无显著性差异。全部复极测量以线性混合公式为基础进行了心率校正。应用索他洛尔后RR间期显著延长(+TdPs: 175±98 msec 和 –TdPs: 201±101 msec, p<0.05)，但两组间药物的心动过缓效应无差别(p=0.34)。 以数值QT间期测量为基础，我们发现基线状态下应用半自动或全自动方法得出的结论是相似的。索他洛尔与QT间期的显著延长相关，且在两组中都是确实存在的(+TdPs: 101±45 和–TdPs: 80±48 msec)。这些变化同基线由统计学差异(p<0.0001)但在组间无差异(p=0.22)。应用计算机方法测量，索他洛尔诱发的QT延长在19毫秒以下，但未达到统计学显著性(+TdPs: 101±45 and –TdPs: 82±54 msec, p=0.28)。

两组中QT, QT 顶点间期显著延长 (p<0. 01)。该延长在统计学显著性上接近于具有TdPs 病史的个体(p<0 两组中QT, QT 顶点间期显著延长 (p<0.01)。该延长在统计学显著性上接近于具有TdPs 病史的个体(p<0.06)，并且通过全部有效导联得到的最大QT间期确认TdPs 是由Kaab等所致。更引人注意的是，索他洛尔显著延长具有TdPs病史组的 TpTe间期(36±41 vs. 6±20 msec, p=0.01)。早期和晚期复极间期(ERD and LRD)的测量确认了基于QT, QT顶点和TpTe间期的观察。两组索他洛尔引起的复极延迟都增加，但有TdPs病史的个体，只是复极过程的晚期部分(LRD70%)显著延长(27±30 vs. 8±13 msec, p=0.03)。 平均来看，(+)TdPs组测量的QT间期延长25毫秒(p=0.06)。根据向量参数ERD30%和 ERD50%，该延长位于复极的早期部分。+TdPs组ERD30% 有 9 毫秒的延长(p=0.02)，ERD50% 则延长了14毫秒(p=0.03).值得注意的是，复极早期的这种延迟并非通过QT顶点间期发现，提示主要是T波形态学测量到了该延迟。

研究 5 结论 个体TdPs 诱因程度的评价对于临床医师和医药公司都是很重要的。我们的结论揭示有TdPs 病史的个体其基线和应用索他洛尔后存在特异性的复极改变。该信息可以帮助心脏专家采取最优化的治疗策略，提高药物安全性评价研究的水平。 89

主要结论 我们的研究显示了服用IKr阻滞剂所致的先天性和后天性LQTS个体的静态和动态的复极异常。基于量化的心电学参数，我们能够测量这些变化。 我们的研究提示复极形态学提供如下相关信息： ----LQTS突变类型的鉴别 ----作为QT延长的补充以帮助诊断LQT2 ----提高通过体表心电图检测药物诱发的Ikr阻滞的检测能力 ----揭示有药物诱发尖端扭转性室速病史患者的体表心电图异常模式。 虽然是初步结果，但这些心电图指标在未来药物相关心脏毒性的评价中可能会起到重要作用。 90

致谢 本次讲座中的研究由以下各位同道合作完成: Drs. Anthony Fossa, Pierre Wicker, James Revkin, Craig Trost, Jack Ostroff : Pfizer Inc, Global Research and Development, CT, USA Dr. Nenad Sarapa, MD: Daiichi Sankyo Pharma Development, NJ, USA Dr. Norman Stockbridge, Michael Li: US-FDA CDER, DC, USA Drs. Stefan Kaab, Martin Hinterseer, Britt-M. Beckmann Ludwig-Maximilians-University, Munich, Klinikum Grosshadern, Department of Medicine 1, Munich, Germany The team of the Heart Research Follow-up Team, University of Rochester, NY 91