QT间期测量与QT间期离散度

ＱＴ间期指的是心室肌开始除极（ＱＲＳ综合波的起点）至心室肌复极终止（Ｔ波的终点）所经过的时间间期，是心室肌电收缩间期的反映，由心室肌的除极时相和复极时相所确定，是传统的常规体表心电图的一个重要组成部分。ＱＴ间期变化的临床重要性知之甚少，并且有不少的争...     

口服氯氮平对QT间期离散度的影响

本研究采用12导联同步体表ECG,比较口服氯氮平(是一种常用的强效抗精神病药)前后的QTd。 1 资料与方法 选择住院精神分裂症患者经询问病史、体格检查,排除器质性心脏病及电解质紊乱,无异常ECG证据,X线胸透及血脂、血糖检查正常。种族相同、年龄25～55(38±5)岁的病人171例,其中男106例,女65例。 受检查者在检查床上静卧10min,统一使用HPM1772A ECG机描记12导联同步体表ECG。病人单用氯氮平开始剂量25mg～50mg/d,逐渐递增,2W内加至治疗量(150mg～400mg/d),服药     

自发性心绞痛心肌缺血对QT离散度的影响

QT离散度 ( QT dispersion,QTd)反映心室复极离散程度 ,即心室肌复极的不均一性。 QTd越高 ,恶性心律失常的发生率越高。本文通过观察 QTd与自发性心绞痛心肌缺血的关系 ,探讨 QTd的临床意义。　　资料和方法　选择在我院和温州医学院附属第一医院的住院患者 ,均经冠状动脉造影明确诊断。其中 ,冠心病患者6 9例 ,男性 45例、女性 2 4例 ,年龄 47～ 71岁平均 ( 5 9.4±5 .4)岁 ,至少一支主要冠状动脉或其分支狭窄≥ 5 0 %即诊断为冠心病。其中 ,1支冠状动脉病变 32例、2支冠状动脉病变2 1例、3支冠状动脉病变 16例 ;陈旧性心肌梗死 2 6…     

急性心肌缺血QT离散度的动态变化

对３５例冠心病患者与１０例健康人测量运动前后ＱＴ离散度，观察急性心肌缺血时ＱＴ离散度的动态变化。结果显示，冠心病组急性心肌缺血时Ｑ离散度明显增加，与对照组为静息时比较均有显著差异（Ｐ〈０．００１），提示急性心肌缺血时ＱＴ离散度增加，发生恶性心律失常的危险度也增加。     

糖尿病患者QT间期与QT离散度分析

心血管损害是糖尿病患者常见的并发症 ,也是当前糖尿病致死的主要原因。现观察一批糖尿病患者体表心电图ＱＴ间期与ＱＴ离散度 ,旨在探讨其临床意义。研究对象 :1999年 8月～ 2 0 0 0年 2月在我院住院和门诊患者经病史 ,空腹血糖和胰岛功能检查诊断明确的 2型糖尿病患者 6 0例。按其是否并发心 ,血管病分为两组。糖 1组 (无并发症组 ) 2 8人 ,男 11人 ,女 17人 ,平均年龄 5 9 5 4± 9 19岁 ,平均病程 8 0 7± 6 30年。糖 2组 (并发心 ,血管病组 )32人 ,男 10人 ,女 2 2人 ,平均年龄经 6 3 19± 9 4 7岁 ,平均病程 8 81± 5 6 2年 ,其中合…     

美托洛尔对心肌梗死后QT间期离散度的影响

预后QT间期离散度（QT dispersion，QTd）是近年来发展起来的一项评价心脏复极同步程度的新指标，同时QTd作为一项预测心脏性猝死、室性心律失常的指标备受国内外学者的关注。我们观察了30例急性心肌梗死（AMI）患者使用阿斯利康制药有限公司生产的美托洛尔（商品名：倍他乐克）治疗前后QTd、QTcd的变化，并与对照组比较，探讨倍他乐克对急性心肌梗死QTd、QTcd的影响。     

急性心肌梗塞早期QT间期离散度、JT间期离散度增加与近期预后的关系

测定１０７例急性心肌梗塞（ＡＭＩ）患者第三心肌梗塞日的ＱＴ间期离散度（ＱＴｄ）和ＪＴ间期离散度（ＪＴｄ）．并以１００例正常人作对照。结果显示：ＡＭＩ组ＱＴｄ、ＪＴｄ较对照组显著增大（均Ｐ＜０．００１）。住院期间死亡组（３Ｏ例）ＱＴｄ与ＪＴｄ较存活组（７７例）明显增大（均Ｐ＜０．００１）。提示以ＱＴｄ、ＪＴｄ增大来评价ＡＭＩ患者的近期预后有一定意义。     

潘生丁试验对QT间期离散度的影响

为了解在潘生丁试验(PET)中QT间期离散度(QT dispersion,QTd)的变化及其临床意义,对50例诊断为冠心病者(A组)作PET并测量其QTd,与45例健康人(B组)比较,结果如下。 1 资料与方法 1.1 临床资料 A组:随机选择1998年1月至     

T离散度诊断冠心病心肌缺血的价值

为探讨QT离散度 (QTd)诊断冠心病心肌缺血的价值 ,记录 5 1例冠心病胸痛发作时 ,发作前、后的 12导联同步体表ECG ,测定并计算QTd、校正的QTd(QTcd)及ST段变化 ,判断有关指标诊断冠心病心肌缺血的灵敏性和特异性。结果 :心绞痛 (AP)发作时QTd及ST段改变显著高于胸痛发作前、后的QTd及ST改变 (分别为 80 .1± 2 2 .4vs4 5 .8± 16 .2 ,4 7.8± 17.0 0ms ,P <0 .0 5 ;0 .12± 0 .0 0 8vs 0 .0 3± 0 .0 0 9,0 .0 2± 0 .0 0 7mV)。QTd增大至≥ 80ms、QTd增加≥ 5 0 %、QTd增加≥ 5 0 %兼≥ 80ms、ST段压低或抬高≥ 0 .1mV诊断心肌缺血的灵敏性分别为 86 .2 7%、80 .39%、78.4 3%、5 2 .94 % ;特异性分别为 90 .70 %、79.0 7%、10 0 %、88.37%。结论 :AP发作时QTd显著增大 ,QTd的有关定量指标可作为诊断冠心病心肌缺血的良好指标 ,其中以QTd增加≥ 5 0 %兼≥ 80ms特异性最好。     

缺血心肌复极离散及迷走神经的保护作用

探讨急性心肌缺血后 ,迷走神经刺激对心室肌不同部位复极时程和复极离散的影响 ,及其对缺血心肌的保护作用。结扎兔冠状动脉左室支 (LVB) ,制备急性心肌缺血模型。分离、结扎并剪断双侧颈迷走、心交感神经 ,电刺激迷走神经外周端。心室复极时程以心外膜电图 (EPG)的QT间期及采用玻璃微电极技术记录的心肌细胞动作电位时程 (APD)表示。分别测定迷走神经刺激前后及缺血前后LVB支配区 (缺血区 )及非支配区 (非缺血区 )的QT间期及APD值。结果 :迷走神经刺激使正常心室肌不同部位的QT间期、APD均有明显缩短 (P <0 .0 5 )。急性心肌缺血后 ,缺血区与非缺血区的QT间期分别是 14 8.6 7± 10 .4 4vs 15 9.5 0± 14 .71ms(P <0 .0 5 ) ;APD90 分别是 :12 8.75±17.84vs 138.0 0± 11.2 2ms(P <0 .0 5 ) ;APD50 分别是 :74 .6 7± 12 .15vs 85 .0 0± 6 .78ms(P <0 .0 5 )。迷走神经刺激后 ,缺血区与非缺血区QT间期、APD差值明显缩小 ,分别是 ,QT间期 :5 .5 8± 1.0 1vs 12 .83± 4 .34ms(P <0 .0 5 ) ;APD904 .5 0± 0 .98vs 11.2 5± 7.0 9ms(P <0 .0 5 ) ;APD50 5 .4 1± 1.2 2vs 12 .5 0± 6 .19ms(P <0 .0 5 )。心肌缺血后心室易损期(VVP)明显延长 34± 2 2 .6 1ms,迷走神经刺激后VVP明显缩短至 11.75± 7.72m     

对QT离散度实质的探讨

为探讨ＱＴ离散度（ＱＴｄ）的真实意义，观察１３９例急性心肌梗死（ＡＭＩ，ＡＭＩ组）及１０９例正常人（对照组）的最长ＱＴ间期（ＱＴｍａｘ）、校正ＱＴｍａｘ（ＱＴｃｍａｘ）及ＱＴｄ的变化。结果：①ＡＭＩ组的ＱＴｍａｘ、ＱＴｃｍａｘ和ＱＴｄ均显著高于对照组（分别为４２２．６０±３０．５１ｍｓｖｓ３８２．４６±２３．４０ｍｓ、４６０．２１±２８．９６ｍｓｖｓ３８８．５１±２０．１５ｍｓ、５９．８０±２８．４０ｍｓｖｓ３９．４３±１２．２１ｍｓ，Ｐ均＜０．００１）。②ＡＭＩ组中发生严重室性心律失常（ＶＡ）患者（１１４例）的ＱＴｍａｘ、ＱＴｃｍａｘ、ＱＴｄ与无ＶＡ的患者（２５例）相比，均有显著差异（分别为４４８．５８±３３．４０ｍｓｖｓ４１６．１０±３５．３０ｍｓ、４８１．４３±３５．１７ｍｓｖｓ４３９．６０±２７．１０ｍｓ、６６．９０±２０．７２ｍｓｖｓ４８．３２±２３．６１ｍｓ，Ｐ均＜０．００１）。认为ＡＭＩ时ＱＴｄ系Ｔ向量环在不同导联上的“投影”差异所引起的，其异常的本质是ＱＴ间期延长     

Association of Corrected QT and QT Dispersion with Echocardiographic and Laboratory Findings in Uremic Patients under Chronic Hemodialysis

Introduction:

Cardiovascular disease is the most common cause of mortality in dialysis patients. Chronic renal failure and hemodialysis (HD) patients may have longer corrected QT (QTc) interval compared with the normal population. Long QTc interval may be a predictor of ventricular arrhythmia and cardiovascular mortality in these patients and hence the aim of this study was the evaluation of the relationship between QTc interval and some echocardiographic findings and laboratory exam results in HD patients.

Materials and Methods:

In a cross-sectional study, 60 HD patients with age >18 years and the dialysis duration >3 months were enrolled. Blood samples were taken, and electrocardiography and echocardiography were done before the dialysis session in the patients.

Results:

Mean age of the patients was 56.15 ± 14.6 years. QTc interval of the patients was 0.441 ± 0.056 s and QT dispersion (QTd) was 64.17 ± 25.93 ms. There was no statistically significant relationship between QTc interval and QTd with duration of dialysis, body mass index, age, and gender (P > 0.05). There was also no significant relationship between QTc interval and QTd with mitral regurgitation, tricuspid regurgitation and aortic insufficiency (P > 0.05). In addition, QTc interval and QTd of the patients had not any correlation with serum parathormon and serum Ca, K, HCO₃ (P > 0.05).

Conclusion:

Based on our results, in HD patients, QTc interval and QTd were not correlated with echocardiographic findings or laboratory exam results. Therefore, it can be concluded that QTc interval prolongation probably has not any correlation with cardiac mortality of the HD patients.     

异氟醚预处理对体外循环后QT离散度的影响

观察体外循环心脏停跳心内直视手术过程中异氟醚预处理对患者QT离散度 (QTd)的影响并探讨其意义。2 0例瓣膜置换术患者 (ASA2～ 3级 ) ,随机分为预处理组和对照组。分别于麻醉后 (T1)、主动脉开放后 15min(T2 )、2h(T3 )、2 4h(T4)时间点取血样 ,检测血清心钠素 (ANP)、心肌钙蛋白I(cTnI)浓度 ;另于术前、术后第 1,3天记录同步 12导联心电图 ,测量QTd和校正QTd(QTcd)。结果 :术后两组QTd和QTcd较术前显著增加 (P <0 .0 1) ,其中对照组增加尤为显著 ,且第 1天时QTd和QTcd值大于预处理组 (70 .38± 8.34msvs 6 0 .84± 9.15ms,89.94± 7.6 5msvs81.6 8± 8.2 3ms,P均 <0 .0 5 ) ;两组ANP于T2 、T3 时有显著升高 (P <0 .0 1) ,且T3 时预处理组明显高于对照组 (5 5 7.89± 84 .0 3pg/mlvs 4 82 .38± 73.4 4 pg/ml,P <0 .0 5 ) ;T3 、T4时 ,对照组cTnI显著高于预处理组 (0 .19± 0 .0 5ng/mlvs0 .13± 0 .0 2ng/mL ,0 .2 4± 0 .0 7ng/mlvs 0 .18± 0 .0 4ng/ml,P <0 .0 1或 0 .0 5 )。结论 :异氟醚预处理能缩短QTd和QTcd ,其机制可能与其减少心肌损伤有关。     

运动试验QT离散度变化与心肌缺血或T波改变相关性的研究

目的 :探讨运动试验QT离散度 (QTd)变化与心肌缺血和T波变化的相关性及评价QTd的临床应用价值。方法 :2 4 2例经冠脉造影证实冠心病而静息心电图正常 ,平板运动试验阳性 (冠心病组 )和 16 8例静息心电图有T波低平、双向、倒置或有u波 ,平板运动试验心电图正常 ,并经冠脉造影及其他检查排除器质性心脏病 (非器质性心脏病组 )。观察两组平板运动试验QTd的变化与心肌缺血和T波变化的相关性。结果 :设QTd >5 0ms为异常 ,冠心病组运动前QTd异常率为18% ,运动后为 80 % ;非器质性心脏病组运动前QTd异常率为 84 % ,运动后为 12 %。QTd的变化与T波改变相关 ,r=0 .86 ,P <0 .0 1;与冠心病运动后单纯缺血性ST段下移无相关性。结论 :运动试验QTd变化与心肌缺血无相关性 ,QTd异常不能判断心肌复极不均一性进而预测恶性心律失常或心脏猝死 ,而只是反映T波非特异性异常的一个粗浅的量化指标     

Effects of Myocardial Perfusion on QT Dispersion in Patients with Hypertrophic Cardiomyopathy

Background: In patients with hypertrophic cardiomyopathy (HCM), myocardial ischemia and myocardial fibrosis as well as ventricular tachyarrhythmia are frequently observed. An increase of heterogeneity of repolarization provided the development of ventricular tachyarrhythmia. The aims of the present study are to evaluate the influence of exercise‐induced myocardial perfusion abnormalities on QT dispersion and to assess whether QT dispersion was involved in ventricular tachycardia (VT) in patients with HCM. Methods: Thirty‐eight patients with HCM and 20 control subjects underwent an exercise stress test, and QT intervals were measured pre‐exercise and at 3 minutes after peak exercise. All subjects underwent thallium (TI)‐201 stress myocardial imaging, and their TI‐201 defect score and exerciseinduced myocardial ischemia were evaluated. Results: Twelve patients (31%) revealed sustained or nonsustained VT. The pre‐exercise QTc dispersion (QTcD) was significantly correlated with the Tl‐201 defect score (r = 0.61, P < 0.0001). The QTcD at 3 minutes after peak exercise was significantly greater in patients with exerciseinduced myocardial ischemia than without exercise‐induced myocardial ischemia (96 ± 36, 72 ± 24 ms^1/2, P < 0.03). The QTcD at 3 minutes after peak exercise was significantly greater in patients with VT than without VT (111 ± 23, 64 ± 17 ms^1/2, P < 0.0001). Conclusion: It is suggested that the degree of myocardial fibrosis influences the pre‐exercise QTcD, and exercise‐induced myocardial ischemia precipitates the increase in the QTcD at 3 minutes after peak exercise in patients with HCM. The increased QTcD at 3 minutes after peak exercise may play a role in identifying patients at a potentially higher risk. A.N.E. 2000;5(1):60–67     

急性心肌梗塞患者福辛普利干预前后校正QT间期离散度的变化

目的 :探讨急性心肌梗塞 (AMI)患者福辛普利 (fosinopril)干预前后校正 QT间期离散度 (QTcd)的变化。　　方法 :46例 AMI患者分基础治疗 福辛普利 10 mg/ d治疗组 (A组 ,2 3例 )和基础治疗组 (B组 ,2 3例 ) ,并对治疗前和治疗 7天后的 QTcd进行对比分析。另设正常人组 2 0例 (C组 )作对照。　　结果 :A组、B组患者 QTcd较 C组明显增加 (P<0 .0 1) ,在 46例 AMI患者中伴室性心律失常者 (n=30 )高于无室性心律失常者 (n=16 ,P<0 .0 1) ,前壁心肌梗塞 (n=31)与下后壁心肌梗塞 (n=15 )间 QTcd差异无显著性 (P>0 .0 5 )。治疗 7天后 A、B两组的 QTcd均较治疗前明显降低 (P均 <0 .0 1) ,但 A组较 B组下降更为显著 ,两组间有显著性差异 (P<0 .0 1)。　　结论 :AMI患者早期 QTcd增加 ,并且与室性心律失常的发生有关 ,福辛普利可降低 AMI早期 QTcd。本结果对改善 AMI近期预后有重要意义。     

Exercise QT Dispersion as an Independent Predictor of the Presence of Ischemia on Myocardial Perfusion Imaging

Background: Increased QT dispersion on resting electrocardiography has been shown to be related to ischemia and to predict adverse cardiac events. The purpose of the present study was to evaluate the relationship between myocardial ischemia and the exercise QT dispersion response. Methods: We studied 368 patients with normal resting electrocardiograms referred for exercise SPECT myocardial perfusion scintigraphy because of suspected coronary disease. We used signal‐averaged recordings of 12‐lead electrocardiograms to manually measure QT dispersion at rest and peak exercise. We interpreted scintigrams visually as ischemic or nonischemic. Results: The 49 patients with scintigraphic ischemia were compared to the 319 patients without ischemia. Resting QT dispersion did not differ, but exercise QT dispersion was significantly greater in those with ischemia (25 ± 13 ms vs 32 ± 15 ms; P = 0.0004). Using logistic regression analysis with any ischemia present or absent as the dependent variable, exercise QT dispersion was an independent predictor (P = 0.0006) of the presence of ischemia. We also found a significant increase in receiver operating characteristic curve area when exercise QT dispersion was included in the model (areas 0.74 ± 0.04 vs 0.78 ± 0.03; P = 0.035). Exercise QT dispersion as a dependent variable was independently associated with sex (increased in women) and perfusion ischemia (positive relation). Conclusion: Exercise QT dispersion is an independent predictor of the presence of scintigraphic ischemia that has incremental value over other clinical and exercise test variables.     

老年心肌缺血者QTc和QTcd变化及临床意义

目的　探讨QTc、QTc离散度(QTcd)与致命性室性心律失常、心源性猝死的关系。方法　测定10 0例老年心肌缺血患者和6 0例心肌梗死患者心电图的QTc间期和QTcd ,并与80例正常老年人进行比较。结果　老年女性患者QTc较男性长(P <0 . 0 5 ) ,而QTcd两者无差异;老年心肌缺血患者QTc和QTcd较正常组明显延长(P <0 .0 1) ;心肌梗死前壁、下壁和后壁3组QTcd无明显差异(P <0. 0 5 ) ;不稳定性心绞痛患者QTcd较稳定性心绞痛长(P <0 . 0 5 )。结论　老年心肌缺血患者QTc和QTcd明显延长,对预测致命性心律失常和心源性猝死有一定价值。