糖尿病对微伏级T波电交替影响的临床分析

目的 T波电交替(TWA)是心肌梗死后、缺血性心肌病、心力衰竭等患者发生心脏性猝死(SCD)的独立预测因子。相关研究报道糖尿病患者发生SCD的风险增加,但缺乏数据表明糖尿病患者微伏级T波电交替(microvoltT-Wave Alternans,MTWA)异常比例增加,本试验主要探讨糖尿病是否使MTWA异常的比例增高。方法选择自2000年1月至2011年5月兰州大学第一医院内科198例行平板运动试验的患者,分为A组:对照组,B组:糖尿病组,C组:冠心病组,D组:糖尿病合并冠心病组。用Logistic回归法对纳入患者MTWA与疾病相关性进行分析,并进一步分析糖尿病患者MTWA异常比例增高与血糖控制水平及病史的相关性。结果 Logistic回归显示异常MTWA与冠心病相关(p<0.001,OR=4.91,95%CI:2.52-9.55),与糖尿病相关(p=0.008,OR=2.39,95%CI:1.26-4.53)。对糖尿病患者进行Logistic回归显示MTWA异常仅与糖化血红蛋白相关(p=0.02,OR=6.00,95%CI:1.37-26.24),与糖尿病病史长短无关。结论 2型糖尿病患者中异常MTWA常见,异常比例为23.40%,MTWA异常比例增加与血糖控制水平具有相关性。     

微伏级T波电交替及其对心脏性猝死的预测价值

微伏级T波电交替(MTWA)是指普通心电图不能发现的需经特殊的、心电信号处理技术才能记录的T波电交替。其发生机制尚不明确,可能与心肌细胞复极的非均一性、离子通道异常和交感活性增加等有关,检测方法有频域法及时域法。MTWA检测能否准确筛选出致死性心律失常的低危患者尚不确定,大多数的临床试验表明,MTWA预测缺血性心脏病、扩张型心肌病和心力衰竭及高血压患者心律失常事件的灵敏度和阴性预测价值较高,而对肥厚型心肌病、遗传性离子通道疾病的应用价值尚需进一步评价。     

急性心肌梗死后患者不同时间的微伏级T波电交替

目的观察急性心肌梗死(简称心梗)后不同时间的微伏级T波电交替(MTWA)。方法用带有TWA移动平均修正技术(TWA MMA)的动态心电图检测系统,以时域法检测45例急性心梗后患者小于1个月、6个月时MTWA。判断标准是:在V3导联Val≥t47μV为阳性,Val≤t47μV为阴性。2次检测均为阴性的归为A组;2次检测,其中1次为阳性的归为B组。结果小于1个月时MTWA阴性占80%,阳性占20%;6个月时MTWA阴性占60%,阳性占40%;6个月时有11例(24.4%)MTWA由阴性转变为阳性,有3例(6.7%)由阳性转变为阴性。这两个时期检测MTWA,结果一致的病人有29例,符合率为64.4%。阴性转阳性患者左室射血分数降低多于持续阴性患者。结论急性心梗后6个月内MTWA处于动态变化之中,对急性心梗后6个月内,MTWA阴性的患者应予更多的关注。     

T波电交替在心脏性猝死预警中的应用——应用T波电交替预警心脏性猝死在中国势在必行

心脏性猝死（Sudden cardiac death，SCD）是一个威胁公共卫生健康的重要社会问题。美国流行病学调查表明，SCD是仅次于各种肿瘤所致死亡的第二大死亡原因。美国平均每年约有45万例心脏性猝死患者。研究证实，约88％的心脏性猝死原因为心律失常，其中恶性室性心律失常最多，约占83％。在发生致命性室性心律失常的人群中，冠心病为主要病因，约占80％。临床研究显示，针对心脏性猝死的高危人群，给予抗心律失常药物治疗不能有效防止SCD。近年来应用ICD一级和二级预防SCD的临床研究证实：ICD可显著减少SCD的死亡率。     

微伏级T波电交替对肥厚型心肌病高危人群的预测价值

目的探讨动态心电图分析系统时域法检测微伏级T波电交替（MTWA）对肥厚型心肌病患者恶性室性心律失常及心脏性猝死的预测价值。方法94例肥厚型心肌病患者（观察组）和105例健康人（对照组）接受24h动态心电图检查并作MTVvA检测,分析两年的死亡、晕厥及恶性心律失常的发生情况。结果对照组MTWA95％正常值参考范围〈36μV。对照组MTWA〉36uV的占10．5％。观察组MTWA〉36uV的占553％。对照组无心血管事件发生;观察组发生恶性心律失常29例,MTWA〉36uV对恶性心律失常诊断的敏感性793％,特异性55．4％;阳性预测值442％,阴性预测值857％。结论MTWA异常的肥厚型心肌病患者发生恶性室性心律失常及心脏性猝死的危险性增加。     

T波电交替计算机检测及其临床研究进展

T波电交替现象可见于长QT综合征、急性心肌缺血、变异型心绞痛、心脏性猝死以及电解质紊乱等。它在预测室性心律失常方面与电生理检查具有高度的一致性,是恶性室性心律失常和心脏性猝死的独立预测指标,是评定恶性心律失常以及心脏性猝死的可信、实用的技术之一。现在,T波电交替已经成为了一种廉价、方便的非侵入式心电检测方法。现综述T波电交替的研究背景、产生机制、检测方法及其临床研究,并简要分析了T波电交替的研究方向和发展前景。     

微伏级T波电交替与焦虑情绪的相关性

目的:分析微伏级T波电交替(Microvolt T wave alternans,MTWA)值和患者焦虑状况的关系。方法:随机选择武汉大学人民医院2012年8月~2013年10月行平板运动试验(treadmill exercise test,TET)的患者136(男59,女77)例,年龄(53±10)岁。采用GE公司提供的Marquette MTWA分析程序,进行标准时域运动试验,记录胸前V1~V6导联的MTWA值,其中最大值以Max Valt表示,并对其进行焦虑自评量表(SAS)的问卷调查,按SAS评分将患者分为焦虑组(38例)和非焦虑组(98例),进行组间比较和相关分析。结果:在峰值心率V3导联两组MTWA值有显著差异(P0.01)。焦虑评分与峰值心率V3导联时的MTWA值呈负相关(r=-0.245,P0.01)。结论:行TET时峰值心率情况下V3导联MTWA与焦虑情绪有相关性。     

应用T波电交替预警心脏性猝死在中国势在必行

心脏性猝死(Sudden car-diac death,SCD)是一个威胁公共卫生健康的重要社会问题。美国流行病学调查表明,SCD是仅次于各种肿瘤所致死亡的第二大死亡原因。美国平均每年约有45万例心脏性猝死患者。研究证实,约88%     

微伏级T波电交替与室性心动过速的临床研究

目的室性心动过速（室速）是器质性心脏病猝死的主要机制.微伏级T波电交替（microvolt T wave alternans,MTWA）是近年来无创评价和预测室速/心室颤动（室颤）及心脏性猝死的新方法.本研究的目的是探讨MTWA与室速的关系及其临床意义.方法用system剑桥心脏诊断系统（Cambridge Heart.Heartwave^TM）,以频谱法检测45例健康志愿者及82例可疑室性心律失常者（其中有资料记载的室速48例）的MTWA.结果MTWA阳性主要见于陈旧性心肌梗死、冠心病、心肌病等,它与室速有一定的相关性（r=0.37,P＜0.01）.器质性心脏病室速组MTWA阳性率高于非器质性心脏病室速组（P＜0.01）,非器质性心脏病室速组MTWA阳性率与健康人组差异无统计学意义（P＞0.05）.MTWA诊断器质性心脏病室速的敏感性75.00%,特异性92.10%,诊断符合率87.03%.结论MTWA与器质性心脏病室速相关,可用于室速患者的危险分层.     

Interpretation and classification of microvolt T wave alternans tests

Measurement of microvolt-level T wave alternans (TWA) during routine exercise stress testing now is possible as a result of sophisticated noise reduction techniques and analytic methods that have become commercially available. Even though this technology is new, the available data suggest that microvolt TWA is a potent predictor of arrhythmia risk in diverse disease states. As this technology becomes more widely available, physicians will be called upon to interpret microvolt TWA tracings. This review seeks to establish uniform standards for the clinical interpretation of microvolt TWA tracings.     

T wave alternans in idiopathic long QT syndrome

Objectives. The study evaluates the association between T wave alternans and the risk of cardiac events (syncope, aborted cardiac arrest or cardiac death) in a large population of patients with idiopathic long QT syndrome.Background. T wave alternans is an infrequently recorded electrocardiographic (ECG) finding in patients with delayed repolarization, and its clinical significance is not clear.Methods. A total of 4,656 ECG recordings in 2,442 patients enrolled in the International Long QT Syndrome Registry were reviewed for episodes of T wave alternans. To determine the risk associated with T wave alternans, independent of corrected QT interval (QTc) duration, patients with T wave alternans were matched for QTc value (every 0.025 s^1/2) to patients with long QT syndrome without T wave alternans.Results. T wave alternans was identified in 39 patients (25 of whom had a QTc interval >0.50 s^1/2). A strong association between QTc prolongation and T wave alternans was observed (odds ratio 1.23 per 0.01-s^1/2unit increase in QTc, p < 0.0001). Conditional logistic regression analyses with adjustment for age, gender, status and QTc value revealed that T wave alternans did not make a significant independent contribution to the risk of cardiac events. The risk of experiencing a major cardiac event was primarily related to length of QTc.Conclusions. T wave alternans, a marker of electrical instability and regional heterogeneity of repolarization, identifies a high risk subset of patients with prolonged repolarization. Patients with T wave alternans have an increased risk of cardiac events, but this risk is primarily related to the magnitude of repolarization delay (QTc prolongation). T wave alternans does not make an independent contribution to the risk of cardiac events after adjustment for QTc length.     

Microvolt T‐wave alternans in early repolarization syndrome associated with ventricular arrhythmias: A case report

Despite early repolarization (ER) syndrome being usually considered benign, its association with severe/malignant ventricular arrhythmias (VA) was also reported. Microvolt T‐wave alternans (MTWA) is an electrocardiographic marker for the development of VA, but its role in ER syndrome remains unknown. A 90‐second 6‐lead electrocardiogram from an ER syndrome patient, acquired with the Kardia recorder, was analyzed by the enhanced adaptive matched filter for MTWA quantification. On average, MTWA was 50 μV, higher than what was previously observed on healthy subjects using the same method. In our ER syndrome patient, MTWA plays a potential role in VA development in ER syndrome.     

Isolated T wave alternans

Two patients with isolated T wave alternans are reported, with their vectocardiograms, their response to carotid sinus stimulation, and the response to calcium infusion in one of them with documented severe hypocalcemia. Eleven cases of the literature are briefly reviewed. The alternans of the T wave appears with severe QT prolongation, QT alternans, and an increased tendency to ventricular fibrillation. The findings are consistent with the hypothesis that T wave alternans may be the electrocardiographic manifestation of the transmembrane action potential alternans and could be related in some cases to hypocalcemia.     

Microvolt T-wave alternans in early repolarization syndrome associated with ventricular arrhythmias: A case report

Despite early repolarization (ER) syndrome being usually considered benign, its association with severe/malignant ventricular arrhythmias (VA) was also reported. Microvolt T-wave alternans (MTWA) is an electrocardiographic marker for the development of VA, but its role in ER syndrome remains unknown. A 90-second 6-lead electrocardiogram from an ER syndrome patient, acquired with the Kardia recorder, was analyzed by the enhanced adaptive matched filter for MTWA quantification. On average, MTWA was 50 μV, higher than what was previously observed on healthy subjects using the same method. In our ER syndrome patient, MTWA plays a potential role in VA development in ER syndrome.     

J wave elevation to monitor quinidine efficacy in early repolarization syndrome

We present the case of a 14-year-old female with early repolarization syndrome who presented with recurrent ventricular fibrillation and ICD shocks which were refractory to multiple drugs and catheter ablation. Treatment with quinidine, an Ito blocker, resulted in a normalization of J waves and suppression of VF. Interestingly, J wave amplitude correlated with the ventricular arrhythmia susceptibility and quinidine levels. The case highlights the importance of quinidine for management of ventricular arrhythmias in the context of early repolarisation and suggests that J wave amplitude may be an important indicator of therapeutic drug levels and arrhythmia susceptibility.     

QT间期延长患者电风暴的临床特点、治疗策略及微伏级T波电交替的预警价值

电风暴（electrical storm,ES）是由于心室电活动极度不稳定所导致的最危重的恶性心律失常,是心脏性猝死的重要原因。本文旨在观察QT间期（QTc）延长患者发作ES的临床特点,B受体阻滞剂防治Es的疗效,并探讨微伏级T波电交替（MTWA）做为一种预警性心电图,对QTc延长伴Es患者的潜在应用价值。