J波伴室性心动过速患者复极离散程度的研究

目的研究J波伴室性心动过速患者心电图复极离散指标QTd、Tp-e间期和Tp-e/QT的变化,探讨其原因。方法心电图记录有J波的患者按照是否发生室性心动过速分为2组。比较患者心电图复极指标。J波伴室性心动过速患者22例,男12例,女10例,平均年龄(52.3±12.3)岁;年龄、性别相匹配的对照组56例,男31例,女25例,平均年龄(51.8±10.1)岁,测量全部入选者同步12导联心电图,测量QTd、Tp-e间期并计算Tp-e/QT值。结果 J波伴室性心动过速组比对照组Tp-e间期[(89.6±15.1)ms比(65.3±14.2)ms,P<0.001]和Tp-e/QT[(0.22±0.05)比(0.16±0.04),P<0.001]比值均增大,差异有统计学意义。QTd间期在两组之间比较[(41.1±3.6)ms比(38.7±3.9)ms,P>0.05],差异无统计学意义。结论 J波伴室性心动过速患者Tp-e间期和Tp-e/QT比值增高反映了跨室壁复极离散度增大,易于发生室性心动过速心律失常。     

Tp-Te间期、Tp-Te/QT比值预测冠状动脉慢血流现象的临床价值

目的:探讨T波峰末间期(Tp-Te间期)、Tp-Te间期与QT间期的比值(Tp-Te/QT比值)与冠状动脉慢血流(CSF)的关系及预测价值.方法:选取2017年1月至2019年10月于郴州市第一人民医院就诊并行冠状动脉造影的患者230例,分为CSF组(n=118)和对照组(n=112),记录患者基础数据;通过心肌梗死溶...     

Tp-Te间期及Tp-Te/QT比率对心功能不全患者的临床应用价值

【摘要】目的 探讨反应心室跨壁复极离散(transmural dispersion of repolarization,TDR)的相关指标T波峰-末间期（Tpeak-Tend interval,Tp-Te）和T波峰-末间期/QT间期比率(Tp-Te/QT)在心功能不全患者中的临床意义及应用价值。方法 105例心功能不全患者及100例正常对照组纳入研究,记录所有入选者的体表心电图Tp-Te间期及Tp-Te/QT比率,以及心率、年龄、BNP等相关临床指标。按照纽约心功能分级(NYHA)将病例组分为低危组(NYHA I-II)及高危组(NYHA III-IV),将高危组中治疗后BNP下降≥30%的患者纳入治疗有效组。分别比较心功能不全患者与正常人相较,心功能不全严重程度不同的患者之间相较,以及高危心功能不全患者治疗前后相较,Tp-Te间期及Tp-Te/QT比率的差异。结果 （1）心功能不全患者与对照组相较Tp-Te间期及Tp-Te/QT比率均明显增加（P＜0.05）;（2）高危心功能不全患者较低危患者的Tp-Te间期及Tp-Te/QT比率明显增大（P＜0.05）;（3）高危心功能不全患者治疗后与治疗前相较Tp-Te间期差距无统计学意义（P＞0.05）,而Tp-Te/QT比率有所降低（P＜0.05）。结论 Tp-Te间期及Tp-Te/QT比率可作为反应心功能不全患者病情严重程度及治疗效果的临床心电学指标。     

AMI病人心电图Tp-Te、Tp-Te/QT与室性心律失常及心功能的关系

目的 分析急性心肌梗死(AMI)病人心电图Tp-Te、Tp-Te/QT与室性心律失常发生及心功能的关系。方法 选取2017年12月—2020年8月徐州市丰县人民医院收治的89例AMI病人作为研究对象,并依照病人是否出现室性心律失常分为室性心律失常组(51例)和无室性心律失常组(38例)。入组后测定其心功能,采用日本福田十二导联同步心电图机对病人心电图进行检查,入院后行24 h十二导联同步动态心电图检查;采用Pearson相关性分析心电图Tp-Te、Tp-Te/QT与心功能指标的相关性,采用线性回归模型分析Tp-Te、Tp-Te/QT与AMI并发室性心律失常的关系。结果 室性心律失常组急性期Tp-Te、Tp-Te/QT水平明显高于无室性心律失常组,差异有统计学意义(P<0.05),两组恢复期Tp-Te、Tp-Te/QT水平比较差异无统计学意义(P>0.05);室性心律失常组每搏量、左室射血分数水平明显低于无室性心律失常组,血清肌钙蛋白I(cTnI)和N末端脑钠肽前体(NT-proBNP)水平明显高于无室性心律失常组,差异均有统计学意义(P<0.05)。高Tp-Te和高T...     

正常儿童心电图Tp-Te间期分析

目的了解性别、年龄对0￣12岁儿童Tp-Te间期的影响,建立该年龄段儿童Tp-Te间期的参考值范围。方法 320例心电图正常的0￣12岁儿童作为研究对象,并按照年龄分为0～3岁、4～6岁,7～9岁,10～12岁组,各组内分男女亚组。测量研究对象12导联心电图Tp-Te间期,取每例研究对象V2～V4导联最大Tp-Te间期为研究指标,并用Bazett公式对Tp-Te间期进行校正。对不同性别、不同年龄组间Tp-Te间期和校正Tp-Te间期进行比较,并求其Tp-Te间期的参考值范围。结果各组内不同性别间心率、Tp-Te间期和校正Tp-Te间期的比较显示,组间均无显著性差异;相同性别Tp-Te间期在0～3岁组和4～6岁组间、7～9岁组和10～12岁组均无显著性差异,而0～3岁、4～6岁组显著低于7～9岁组和10～12岁组;校正Tp-Te间期在女性各年龄组间无显著性差异;在男性10～12岁组高于0～3岁组和4～6岁组,其他各年龄组间无显著性差异;Tp-Te间期正常值参考范围为:0￣6岁49.3￣112.3ms,7￣12岁62.9￣119.2ms;校正Tp-Te间期正常值参考范围为:0￣6岁63.6￣141.2ms,7￣12岁71.5￣141.3ms;结论 0～12岁儿童性别对Tp-Te间期和校正Tp-Te间期没有影响,随年龄增长,Tp-Te间期延长而校正Tp-Te间期变化不大。Tp-Te参考值上限为0￣6岁112.3ms,7￣12岁119.2ms;校正Tp-Te参考值上限为0￣12岁141.3ms。     

心电图Tp-Te间期、Tp-Te/QT比值与恶性室性心律失常的关系

目的探讨心电图T波峰末间期(Tp-Te)、Tp-Te/QT比值对恶性室性心律失常(MVA)的诊断价值。方法连续入选2017年1月1日至2018年1月1日于保定市第一中心医院西院心电图、脑电图二室行24 h 12导联动态心电图检查的患者412例为研究对象。根据是否发生恶性室性心律失常分为两组:恶性室性心律失常组72例;无恶性室性心律失常组340例。分别测定两组患者Tp-Te间期、QT间期,计算出Tp-Te间期、QTc间期及Tp-Te/QT比值,并对两组患者Tp-Te间期、QTc间期及Tp-Te/QT比值进行统计学分析。结果恶性室性心律失常组的Tp-Te间期、Tp-Te/QT比值均较非恶性室性心律失常组明显增加(P0.001)。结论 Tp-Te间期、Tp-Te/QT比值增加对于恶性室性心律失常的发生均有预测价值。     

高血压左心室肥厚患者心电图QT离散度改变

目的　探讨原发性高血压左心室肥厚患者心电图QT离散度 (简称QTd)变化。　方法　用美国超九 ATL(XO16 3)彩色多谱勒诊断仪二维超声测量其舒张期左心室室间隔厚度和左心室后壁厚度 ,以≥ 1 2cm作为左心室肥厚诊断标准 ,对高血压左心室肥厚组 (n =36 ,男 女 =2 0 16例 ,平均年龄 6 0岁± 12岁 )、高血压左心室非肥厚组(n =5 0 ,男 女 =30 2 0例 ,平均年龄 6 2岁± 12岁 )进行测量 ,再用心电图ECG 8110P( 0 180 8A3)描记其常规 12导联心电图 ,手工测量其最大QT间期 (QTmax)、最小QT间期 (QTmin)和心动周期RR间期 ,计算QTd和心率校正的QTcd ,并随机匹配正常人群组 (n =4 0 ,男 女 =2 4 16例 ,平均年龄 5 8岁± 13岁 )。　结果　高血压左心室肥厚组QTd为6 0ms± 17ms ,QTcd为 6 8ms± 2 4ms,高血压左心室非肥厚组QTd为 4 1ms± 13ms,QTcd为 4 3ms± 17ms ,正常人群组QTd为 4 3ms± 11ms ,QTcd为 4 4ms± 16ms,前两组比较有显著性差异 ,P <0 0 1,后两组比较无显著性差异 ,P >0 0 5。　结论　原发性高血压左心室肥厚患者QT间期离散度增大。     

QT离散度不能反映心肌复极的区域性差异

目的　探讨体表心电图上QT离散度 (QTd)是否可以反映区域性的心肌复极差异。方法　正常对照 (对照 )组和心肌梗死 (心梗 )组各有 12 0例 ,记录同步 12导联心电图 ,人工测量各导联QT间期 ,计算QTd。结果　与对照组相比 ,心梗组QTd明显增加 ,分别为 (5 6 3± 17 8)ms与 (10 0 9±5 4 3)ms,P <0 0 0 1;但两组之间存在很大交叉 ,无法确立参考值。最长QT和最短QT在两组的导联分布呈现一致趋势。心梗组全部 12导联QT间期均较对照组明显延长 ,平均QT间期分别为 (397 0± 4 6 8)ms与 (36 7 3± 2 2 8)ms ,P <0 0 0 1。不同梗死部位各亚组之间心电图各导联QT间期均值差异无显著性(P =0 6 36 ) ,未见到与梗死部位相关的区域性QT间期改变。结论　QTd增大常与QT间期延长同时出现 ,QTd增大从整体上反映了心肌复极异常 ,但是不能代表心肌复极的区域性差异。     

小儿扩张型心肌病QT间期离散度测定

目的　探讨小儿扩张型心肌病心电图QT间期离散度 (QTd)改变。　方法　用广东中山博爱心电综合自动分析仪 (SR 10 0 0A)分别采集 4 5例扩张型心肌病患儿 (男 30例 ,女 15例 ,年龄 2岁～ 14岁 ,平均年龄 6 8岁±3 6岁 ) 12导联心电图和 4 0例健康小儿 (男 2 5例 ,女 15例 ,年龄 1岁～ 14岁 ,平均年龄 7 4岁± 3 4岁 )心电图 ,录入软盘 ,计算机回放并程序放大波形 2倍～ 4倍检测 ,增益 1mv =2 0mm 40mm ,纸速 5 0mm s～ 10 0mm s ,测量QTmax、QTmin ,计算QTd(QTmax QTmin) ,微机数理统计。　结果　扩张型心肌病伴室性心律失常组 (12例 )QTd为 6 8 4ms±12 1ms,扩张型心肌病不伴室性心律失常组 (33例 )为 4 4 3ms± 9 3ms ,健康小儿组为 2 7 7ms± 8 5ms ,组间比较方差分析P <0 0 1。　结论　扩张型心肌患儿心电图QT间期离散度增大 ,易于发生室性心律失常。     

急性心肌梗死早期患者QT离散度的变化及其意义

目的探讨急性心肌梗死（acute myocardial infarction,AMI）早期患者QT间期离散度（QT dispersion,QTd）的变化及其意义。方法回顾性分析51例AMI患者（AMI组）（包括39例无心室颤动患者及12例心室颤动患者）和48名健康体检者（对照组）的心电图资料,比较AMI组与对照组的QTd和QTcd、39例无心室颤动患者及12例心室颤动患者的QTd和QTcd。结果AMI组入院后即刻行标准12导联心电图检查,对照组选择15min后行静息心电图检查,测量并计算QTd。AMI组QTd、QTcd明显高于正常对照组,差异有统计学意义[（69．9±20．3）ms比（32．5±12．6）ms,P〈0．01;（85．3±32．8）ms比（40．9±15．7）ms,P〈0．01];AMI组中心室颤动组QTd、QTcd明显大于无心室颤动组,差异有统计学意义[（112.3±22）ms比（59．6±21．5）ms,P〈0．01;（120．1±12）ms比（68．1±22．4）ms,P〈0．01}。结论AMI早期QTd增高,QTd的延长对预测AMI患者的严重室性心律失常有重要的临床价值。     

急性心肌梗死恢复期患者平板运动试验Q-T间期离散度的价值研究

目的 探讨急性心肌梗死恢复期患者运动试验后Q-T间期离散度（Q-Td）的变化.方法 观察51例急性心肌梗死恢复期患者（观察组）平板运动试验的Q-Td的变化,并观察运动后出现严重室性心律失常、胸痛、血压下降与Q-Td变化的关系.结果 患者峰心率时Q-Td（64.3±20.5ms）较运动前（51.2±23.5ms）增大,差异有显著统计学意义（P＜0.01）.运动中出现严重室性心律失常或明显胸痛、血压下降者15例（A亚组）与36例未出现者（B亚组）比较,运动前Q-Td差异无统计学意义（59.1±17.5ms和16.3±19.2ms,P ＞0.05）,峰心率时A亚组Q-Td（76.8±15.5ms）较B亚组（60.1±16.1ms）延长,差异有显著统计学意义（P＜0.01）.两亚组Q-Td多壁梗死均比单壁梗死延长,A亚组多壁梗死比B亚组延长,差异均有统计学意义（P ＜0.05）.结论 急性心肌梗死患者运动后Q-Td进一步增大,出现严重室性心律失常的危险性增大.平板运动试验可作为筛选急性心肌梗死高危人群的手段之一.     

The D-allele of the ACE polymorphism is related to increased QT dispersion in 609 patients after myocardial infarction.

AIMS: Prolongation of QT dispersion can be observed in some patients with myocardial infarction and serves as a possible independent risk factor for sudden cardiac death. Angiotensin-converting enzyme (ACE) inhibition has been shown to reduce QT dispersion in myocardial infarction patients. We hypothesized that ACE gene I/D polymorphism, which is known to modulate ACE activity, may also affect QT dispersion after myocardial infarction. METHODS AND RESULTS: We studied 609 myocardial infarction patients (532 men, aged 56.1+/-0.3; mean 5.5 years after myocardial infarction) from a population-based myocardial infarction register by standardized questionnaire, anthropometry, ECG, echocardiography, and genotyping of ACE I/D polymorphism. In addition, 540 unaffected siblings (251 men, age 54.6+/-0.4 years) of these patients were studied by the same protocol. As compared with their healthy siblings, mean QT dispersion was prolonged in myocardial infarction patients (65.9+/-1.4 ms vs 91.2+/-2.3 ms, respectively, P<0.001). QT dispersion was negatively correlated to left ventricular ejection fraction (P<0.005). The ACE DD-genotype was associated with longer QT dispersion in myocardial infarction patients (103.0+/-4.6 ms vs 81.9+/-4.5 ms in the II group, P<0.001). This association was noted to be strong in multivariate analyses that included age, gender, ejection fraction, left ventricular end-diastolic diameter, medication, and heart rate. In contrast, no association between the ACE DD-genotype and QT dispersion was detected in healthy siblings of myocardial infarction patients. CONCLUSION: Thus, the ACE D-allele may be associated with increased QT dispersion in patients after myocardial infarction but not in healthy subjects. An interaction of myocardial damage and genetic predisposition that both enhance the activity of the renin angiotensin system may decrease the repolarization homogeneity of the heart.     

QT dispersion as a predictor of long-term mortality in patients with acute myocardial infarction and clinical evidence of heart failure.

BACKGROUND: QT interval dispersion is a marker of inhomogeneous ventricular repolarization, and therefore has the potential to predict re-entry arrhythmias. Following acute myocardial infarction, increased QT dispersion has been associated with a higher risk of ventricular arrhythmias. However, whether or not QT dispersion predicts prognosis post-acute myocardial infarction is not clear. We addressed this issue by analysing the AIREX study registry. METHODS: AIREX was a follow-up study of 603 post-acute myocardial infarction patients who exhibited clinical signs of heart failure and were randomly allocated to ramipril or placebo. An interpretable 12-lead ECG obtained between day 0 and day 9 after the index infarction (median time 2 days) was available in 501 patients. We examined whether QT dispersion was a predictor of all-cause mortality in the AIREX study registry (mean follow-up 6 years). RESULTS: QT dispersion measurements were significantly increased in patients who subsequently died (QT dispersion: 92.0 +/- 38.5 ms vs 82.7 +/- 34.3 ins. P=0.005; rate corrected QT dispersion: 105.7 +/- 42.7 ms vs 93.1 +/- 35.9 ms, P<0.001). Univariate analysis showed that QT dispersion as a predictor of all-cause mortality risk (QT dispersion: hazard ratio per l0 ms 1.05, [95% CI 1.02 to 1.09]. P= 0.004; rate corrected QT dispersion: 1-07 [1.03 to 1.10], P<0.001): an increase of 10 ms added a 5-7%, relative risk of death. QT dispersion remained an independent predictor of all-cause mortality risk on multivariate analysis (QT dispersion: 1.05 [1.01 to 1.09], P=0.027; rate corrected QT dispersion: 1.05 [1.01 to 1.09]. P=0.022). CONCLUSION: QT dispersion. measured from Li routine 12-lead ECG following acute myocardial infarction complicated by heart failure provides independent information regarding the probability of long-term survival. However. the low sensitivity of this electrocardiographic marker limits its usefulness for risk stratification if used in isolation.     

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     

Effect of balloon inflation-induced acute ischemia on QT dispersion during percutaneous transluminal coronary angioplasty

Background: QT dispersion (QTd = QT_max - QT_min) measured as interlead variability of QT interval reflects the spatial inhomogeneity of ventricular repolarization times, and increased QTd may provide a substrate for malignant ventricular arrhythmias. Ischemia is associated with regional abnormalities of conduction and repolarization. Hypothesis: This study aimed to investigate the effect of acute ischemia on QTd during successful percutaneous transluminal coronary angioplasty (PTCA). Methods: Forty-three patients (10 women, 33 men, mean age 56 years) were enrolled in the study. Electrocardiogram (ECG) recordings were taken before PTCA and during balloon inflation period. QT maximum (QT_max), QT minimum (QT_min), and QTd (QT_max - QT_min) values were calculated from the surface ECG. Results: There was no difference among QT_max values (p = 0.6). Mean QT_min during balloon inflation was lower than before PTCA (368 ± 45 vs. 380 ± 41 ms, p = 0.002). The difference between QTd values before and during balloon inflation was statistically important (65 ± 9 vs. 76 ± 10 ms, p = 0.001). This difference is caused by a decrease in QT_min during balloon inflation. Conclusion: Acute reversible myocardial ischemia induced by balloon inflation causes an increase in QTd value, and this increment is the result of a decrease in QT_min interval. Therefore, QTd may be a marker of reversible myocardial ischemia.     

Dispersion of the QT Interval in Subjects with Frequent Nonsustained Ventricular Arrhythmias and No Underlying Heart Disease: Arrhythmogenic Substrate or Mechanoelectrical Feedback of Arrhythmias?

Background: QT dispersion (QTd) on the ECG is thought to reflect the temporal and spatial inhomogeneity of repolarization in the underlying myocardium. In myocardial infarction, ischemia, and long QT syndromes, an increased QTd is associated with a propensity for malignant ventricular arrhythmias and sudden cardiac death. We investigated this feature of the repolarization process in subjects with frequent ventricular arrhythmias and structurally normal hearts. Methods: Forty‐nine patients referred for frequent, nonsustained ventricular arrhythmias (45 ± 14 years, ×± SD, 61% female) had normal ventricular dimensions and function, no late potentials, and normal ECG. They were compared with 30 controls (42 ± 13 years, 50% female). QTd was measured as the difference between the longest and the shortest QT in the six precordial leads at a paper speed of 50 mm/s. Results: In patients, QTc was similar to that of controls: 395 ± 21 versus 386 ± 20. However, QTd was greater: 49 ± 20 ms versus 32 ± 14 ms, P < 001. Moreover, 18 patients (36%) had QTd exceeding 60 ms—a value superior to the mean normal value of 2 SD—compared to only 1 control (3%) (P < 0.01). Finally, patients with more frequent ventricular arrhythmias had larger QTd. Conclusions: In patients with frequent nonsustained ventricular arrhythmias and otherwise normal hearts, QT interval dispersion is increased. We speculate that, instead of representing a specific electrophysiological substrate of arrhythmias, QT dispersion in this specific population could result from arrhythmias themselves through a possible mechanoelectrical feedback.     

An Evaluation of the Impact of Gender and Age on QT Dispersion in Healthy Subjects

Objectives: To determine if gender, age, and gender per age category, have an impact on QT and QTc dispersion in healthy volunteers. Methods: This study was undertaken in 150 patients (50 per age group, 75 males, 75 females). The age groups included young (20–40 years), middle‐aged (41–69 years) and elderly (> 70 years) subjects. The QT intervals on a 12 lead ECG were determined and Bazett's formula was used to derive the QTc intervals. The QT and QTc dispersion were determined by subtracting the shortest QTc interval from the longest on each 12‐lead recording. Results: Males had higher QT dispersion than females (50 ± 22 vs 42 ± 18 ms, P = 0.017) but QTc dispersion was not significantly changed. No significant differences were seen among the different age categories for QT or QTc dispersion. In elderly subjects, males had higher QT and QTc dispersion than females (54 ± 23 vs 42 ±15 ms, P = 0.039 and 63 ± 23.7 vs 48 ± 21 ms, P = 0.032, respectively). Conclusions: When evaluating the effect of gender in different age categories, elderly males have significantly greater QT and QTc dispersion than elderly female subjects. No other gender differences were noted for QT or QTc dispersion in the other two age categories. When evaluating a population of healthy volunteers, regardless of age, gender has an impact on QT dispersion but no significant interaction with QTc dispersion. Evaluating age without dividing the data by gender yields no significant differences in QT or QTc dispersion. A.N.E. 2001;6(2):129–133     

QT Dispersion Increases with Aging

Background: Age‐related changes in cardiovascular system are well‐known. Arrhythmias in elderly patients constitute most of the urgencies, consultations, or hospitalizations. QT dispersion (QTd) is a simple noninvasive arrhythmogenic marker to demonstrate the electrical instability of the heart. The aim of this study was to investigate how QTd changes with increasing age by calculating the QTd in the elderly and younger subjects. Methods: One hundred and forty‐six consecutive subjects (62 males and 84 females; age range: 18–82 years) were enrolled in the study. Sixty‐seven of the subjects were 65 years and over (mean age, 70 ± 4), 79 were younger than 65 (mean age, 37 ± 11). A 12‐lead ECG was recorded. The longest and the shortest QT intervals were measured manually on these ECG recordings. QTd was calculated from the formula, QTd = QTmax ? QTmin. Results: Demographic features were similar between the two groups. QTd of the elderly group was found to be significantly higher than the younger group (35.6 ± 15.6 in elderly, 24.2 ± 12.4 in younger group, P < 0.001). A positive relationship was found between QTd and age (r = 0.415, P < 0.001). QTd was greater in female than in male (31.9 ± 16.7 ms vs 26.0 ± 11.3 ms, respectively, P = 0.018). Conclusions: Our study shows that QTd increases with advancing age. We think that long‐term follow‐up of these patients would be useful to show if there is any relationship between the clinical outcomes and the increase in QTd.     

QT Dispersion and Viable Myocardium in Patients with Prior Myocardial Infarction and Severe Left Ventricular Dysfunction

Background: QT dispersion (QTd) has been found to correlate to the amount of viable myocardium in patients with Q‐wave myocardial infarction and well‐preserved LV function. However, this relationship is unknown in patients with severe left ventricular dysfunction. Methods: Thirty‐four patients with prior large myocardial infarction and severe left ventricular dysfunction underwent Tc‐99m sestamibi single photon emission cardiac tomography (SPECT) and F‐18 fluorodeoxyglucose (FDG) SPECT. Viability was defined as a defect relative count density (DCD) of at least 20% greater on FDG SPECT. QTd, corrected QT dispersion (QTcd), and QT coefficient of variation (cv) in patients with viable myocardium was compared to those without viable mvocardium in the infarct area. Results: Thirteen patients were excluded from analysis for poor FDG images or inadequate ECG tracings. Of the remaining patients, 10 (48%) were found to have viability on FDG SPECT. QTd, QTcd, and QTcv in patients with viability were: 58 ± 22 ms, 61 ± 23 ms, and 4.81 ± 1.76%, respectively, which did not differ significantly from those in patients without viability (QTd = 56 ± 14 ms, QTcd = 70 ± 16 ms and Qtcv = 5.06 ± 1.20% (P = NS]). Moreover, neither FDG defect size, nor LVEF correlated with QTd. Conclusions: This study indicates no relationship between QTd and viability in patients with myocardial infarction and severe left ventricular dysfunction. A.N.E. 2002;7(1):53–59     

直接经皮腔内冠状动脉成形术对急性心肌梗塞QT离散度的影响

目的　研究急性心肌梗塞 (AMI)患者应用直接经皮腔内冠状动脉成形术 (PTCA)对 QT离散度(QTd)的影响。方法　回顾 95例 AMI患者 ,通过测量入院时及入院后不同时间心电图 ,计算校正 QTd(QTcd)。对比分析其中 68例 PTCA再通患者 (PTCA组 )与 2 7例未行 PTCA或溶栓患者 (对照组 )不同时间 QTd与 QTcd的变化。结果　 PTCA组再通即刻 QTd、QTcd较再通前明显延长 (P<0 .0 1 ) ,2小时后恢复到入院时水平 ,4小时后较入院时明显缩短 (P<0 .0 1 ) ,以后 2 4小时内相对稳定。对照组入院后 2 4小时内 QTd、 QTcd变化不大 (P>0 .0 5 )。结论　 AMI患者应用成功的 PTCA治疗可以缩短心室复极的 QTd,但再灌注即刻可加重心室复极的 QTd