QT间期离散度及其临床应用

众所周知,体表心电图上QT间期可反映整个心肌复极化过程。自1985年Campbell等首先描述了体表心电图不同导联QT间期存在微小差异以来,越来越多的证据提示,各导联间QT间期的这种离散性并不是记录的伪差,而可能是心室肌复极障碍的反映,代表不同区域心肌复极的时间差异。由此提出了QT间期离散度这一概念,指同步记录的体表12导联心电     

运动负荷对缺血心肌QT间期离散度的影响

目的：探讨运动对缺血性心脏病（ＩＨＤ）ＱＴ离散度的影响及β受体阻滞剂的干预作用。方法：观察２７例ＩＨＤ（ＩＨＤ组）,２４例接受β１受体阻滞剂治疗的ＩＨＤ（ＩＨＤ－β组）和１４例正常人（正常组）静息和平板运动高峰时ＱＴ间期有其相关参数。结果：静息和运动高峰时ＩＨＤ和ＩＨＤ－β组ＱＴ间期较正常组显著延长,但心率校正后差异无显著性。ＩＨＤ与正常组比较,静息时ＱＴｄ,ＱＴｃｄ,运动高峰时ＱＴｄ,ＱＴｃｄ均     

QT间期离散度增加与急性心肌梗塞预后的关系 (附30例AMI病例分析)

目的：探讨AMI近期预后的预测价值。方法：对30例急性心肌梗塞（AMI）患者的QT间期离散度（QTd)进行分析，结果：室性心动过速（VT）、心室颤动（Vf）及猝死者的QTd明显长于无VT、Vf及非猝死者（P＜0．01），前壁心肌梗塞组QTd明显长于后壁心肌梗塞组（P＜0．01）。结论：QTd是预测AMI近期预后的一项敏感指标。     

急性心肌梗塞患者QT间期离散度的变化及其临床意义

急性心肌梗塞患者ＱＴ间期离散度的变化及其临床意义甘肃省人民医院心内科陈绍良，谢丹红，徐祖玲许多研究表明，ＱＴ间期离散度（ＱＴｄ）较之ＱＴ间期更能准确反映心肌复极时间离散度。因此，ＱＴｄ对于判断急性心肌梗塞（ＡＭＩ）患者的预后具有十分重要的作用［１～６...     

急性心肌梗塞溶栓治疗对QT间期离散度及JT间期离散度的影响

观察５２例急性心肌梗塞（ＡＭＩ）ＱＴ间期离散度（ＱＴｄ）及ＪＴ间期离散度（ＪＴｄ）在溶栓前后的变化。结果表明：溶栓成功血管再通组３８例,溶栓前后ＱＴｄ、ＪＴｄ差异有极显著意义（Ｐ〈０．０）;溶栓失败血管未通组１４例,溶栓前后ＱＴｄ,ＪＴｄ差异无显著意义;且溶栓后２４小时ＱＴｄ,ＪＴｄ延长最大,发病１周后两组ＱＴｄ,ＪＴｄ基本恢复,提示ＡＭＩ溶栓后ＱＴｄ,ＪＴｄ的变化可作为判断溶栓成功的无创性指标。     

急性心肌梗塞溶栓治疗后的QT离散度变化

ＱＴｃｄ增大对预测急性心肌梗塞后恶性心律失常和心脏猝死的发生已有较多报道 ,溶栓治疗能减少急性心肌梗塞的死亡率。本文通过４８例急性心肌梗塞患者溶栓前后ＱＴｃｄ的变化 ,探讨溶栓治疗对ＱＴｃｄ的影响。１材料与方法１．１对象１９９３年１０月～２００１年１０月收治的首次急性心肌梗塞患者４８例 ,男３０例 ,女１８例。年龄４０～６７岁 ,平均 (５０±３．５)岁。其中前壁心肌梗塞３５例 ,下壁心肌梗塞１３例。全部病人均有心电图及血清酶证实 ,除外血电解质紊乱、房颤及束支传导阻滞患者。接受溶栓治疗的条件为 :入院距发病时间…     

QT,JT间期离散度与急性心肌梗塞预后的关系

QT间期离散度(QTd)是指心电图(ECG)各导联间QT间期的变异程度。其产生与心肌细胞除极后复极不均匀有关。QTd延长与致命性室性心律失常的发生密切相关,而致命性室性心律失常是急性心肌梗塞(AMI)的主要死因,因此将其作为AMI预后的一项指标已越来越受到关注。本文通过对200例AMI患者QTd和JTd的动态观测,探讨如下。     

QT间期离散度对急性心肌梗塞后早期室颤的预测价值

ＱＴ间期离散度对急性心肌梗塞后早期室颤的预测价值杨顺来刘兆昶姜意存王静急性心肌梗塞（ＡＭＩ）是病死率较高的心脏病急症，原发性室颤是早期死亡的主要原因，目前临床上常用心室晚电位（ＶＬＰ）及心率变异（ＨＲＶ）来预测，因需特殊设备不易在临床上广泛使用，且其...     

QT Dispersion Does Not Predict Early Ventricular Fibrillation After Acute Myocardial Infarction

Ventricular arrhythmias may be associated with increased QT dispersion (difference between maximum and minimum QT on standard 12-lead ECG). We performed a case control study to determine if QT dispersion on the admission ECG could predict early VF after acute myocardial infarction. The cases were 24 patients with acute myocardial infarction (14 inferior, 8 anterior, and 2 lateral) with VF within 12 hours of admission. There were 24 control patients without VF matched for site of infarction and ST segment score (sum of ST segment elevation). VF occurred a median of 153 minutes (interquartile range 93–245) after onset of chest pain and 33 minutes (range 7–104) after initial ECG. QT (399 ± 37 and 394 ± 37), QT corrected (440 ± 38 and 429 ± 29), and QT dispersion (68± 20 and 66 ± 27) were similar in patients and controls. By design, ST score was similar (11 ± 9 vs 9 ± 5 mV), although a good match could not be obtained for three patients with extreme ST elevation. Patients with VF presented to the hospital earlier after the onset of chest pain (median 95 min [range 65–188] compared to 150 min [range 80–270], P= 0.05) and had a lower serum sodium (138 ± 2.4 vs 140 ± 2.5, P = 0.05) than controls. Thus, QT interval and QT dispersion, measured on the presenting ECG, did not predict early VF after myocardial infarction.     

急性心肌梗塞时心前导联QTc离散度对心室颤动的预测作用

目的　探讨急性心肌梗塞时 (AMI) QT间期离散度增加和心室颤动易感性之间的关系。方法　比较分析2 0例 AMI发病后 2 4h内并发心室颤动的患者 (心室颤动组 )和 2 0例未发生心室颤动的 AMI患者 (对照组 )在急诊入院时体表同步 12导心电图的心前 QT间期离散度和 QTc间期离散度。结果　心室颤动组 QTc间期离散度和 QT间期离散度均显著高于对照组 (分别为 70 ms± 30 ms与 32 ms± 15 ms和 6 7ms± 30 ms与 31ms± 17ms,P<0 .0 0 1)。结论　AMI时心前 QT间期离散度增加产生心室颤动的危险性增加     

Does Atrial Fibrillation Beget Ventricular Fibrillation in Patients with Acute Myocardial Infarction?

Background: Atrial fibrillation (AF) is associated with increased mortality and a higher complication rate postmyocardial infarction (MI), but the exact mechanisms are unknown. We investigated whether AF predisposes to ventricular arrhythmia in postmyocardial infarct patients, thereby accounting for increased mortality. Methods: Five hundred consecutive patients admitted to our coronary care unit with acute MI were monitored for in‐hospital arrhythmias. Detailed information was also compiled on past history, co‐morbidities, electrolyte disturbances, drug therapies, and ejection fraction. Mortality data were collected for an average of 5.5 years. Results: The results have shown that the incidence of ventricular fibrillation (VF) is much greater in patients presenting with AF (P = 0.03) and multivariate analysis has shown that AF is independently associated with the development of VF. This association occurs principally in patients who are admitted with AF (P = 0.01) rather than those who develop it during their admission, although these patients are also at mildly increased risk. The increased incidence of VF does account for increased mortality in the AF patients but does not explain all of their excess risk. There was no association between AF and ventricular tachycardia (VT); P = 0.50. Conclusions: In conclusion, AF on admission to the hospital with acute MI is associated with an increased risk of VF and subsequent mortality.     

QT-Related Rate-Responsive Pacing During Acute Myocardial Infarction

We studied the findings in a patient who had a TX 915 pacemaker and who was suffering from an acute inferior myocardial infarction. On admission, we observed pacing at the upper rate limit due to excessive adrenergic tone. Shortly thereafter a strong vagal reaction occurred, and the pacing rate fell back to the lower rate limit. This condition was improved with atropine. Conclusions: (1) In the described condition the TX pacemaker behaved in a very "physiological" fashion; (2) Sudden strong cholinergic activity lengthened the QT interval; (3) Programming of a steep slope must be avoided in coronary artery disease; (4) Stimulus-T-wave intervals at maximal adrenergic and cholinergic stimulation should be taken into account when programming the slope and the T-wave sensing window.     

Influence of Early Coronary Reperfusion on QT Interval Dispersion After Acute Myocardial Infarction

We studied the influence of early coronary reperfusion on QT interval dispersion in patients with acute myocardial infarction (MI). Tbere were 54 males and 18 females witb a mean age of 60 ± 10 years. Of the 51 patients with recanalization of the infarct related vessel in the recovery phase, 28 (group A) had early coronary reperfusion (5.5 ± 2.7 bours), 23 other patients (group B) were not confirmed with early coronary reperfusion. Twenty-one patients (group C) did not undergo recanalization of the infarct related vessel in the recovery phase. Corrected QT (QT_c) maximum, QT_c minimum, and QT_C dispersion calculated as tbe difference between the maximum and minimum QT_c intervals, were compared among these three groups at both acute and recovery phase. At the acute phase after MI, there were no significant differences in the QT_c maximum, QT_c minimum, QT dispersion, and QT_c dispersion among these three groups. At the recovery phase after MI, there were also no significant differences in the QTc maximum and QTc minimum. However, there were significant differences in the QT dispersion (0.035 ± 0.010 in group A, 0.049 ± 0.015 in group B, and 0.061 ± 0.031 s in group C, respectively; P = 0.0001), and QT_c dispersion (0.038 ± 0.012 in group A, 0.050 ± 0.015 in group B, and 0.063 ± 0.032 s in group C, respectively; P = 0.0003) among the three groups. Comparison of QT_c dispersion between acute and recovery phase revealed significant reduction from acute to recovery phase in group A. The number of premature ventricular contraction was lower in groups A and B than group C. In summary, early coronary reperfusion may reduce electrophysiological instability by reducing QT dispersion in the recovery phase after acute MI.     

直接经皮腔内冠状动脉成形术对急性心肌梗死QT离散度的影响

目的：观察直接经皮腔内冠状动脉成形术（PTCA）对急性心肌梗死（AMI）患者QT间期离散度（QTd)的影响。方法：采用标准12导联心电图,对直接TPCA组26例和未再灌注治疗组30例AMI患者行心电图描记,分别测量入院时、直接PT-CA后2h、24h、1周、2周的QTd值,并观察两组恶性室性心律失常事件的发生。结果：直接PTCA组与未再灌注治疗组入院时QTd无差异（P＞0.05),直接PTCA组除术后2hQTd一过性增大外,24h后明显缩小,与未再灌注治疗组比较差异显著（P＜0.01),同期直接PTCA组恶性室性心律失常发生率低（P＜0.01)。结论：AMI后直接PTCA能缩小患者QTd,并能降低急性期恶性室性心律失常事件的发生。     

急性心肌梗死患者溶栓前后QT离散度的变化

目的:观察急性心肌梗死(AMI)患者溶栓前后QT离散度(QTdispersion,QTd)的变化及早期再灌注对QTd的影响。方法:对61例AMI患者给予尿激酶静脉溶栓治疗,予溶栓前及溶栓2h后同步记录18导联心电图,分别测量成功组及失败组的QTd,并进行前后比较。结果:溶栓后再通41例,溶栓后未通20例。血管未通组其QTd较前减少,但无统计学意义(P>0.05),溶栓后再通组其QTd较血管未通组降低程度更大,有统计学意义(P<0.01)。结论:QTd可作为评价AMI患者溶栓后判断溶栓成功与否的一项临床早期参考指标。     

心室复极指标对急性心肌梗死恶性室性心律失常的预测价值

目的:探讨J波、ST段墓碑型抬高、Q-T间期离散度(QTd)、J-T间期离散度(JTd)预测急性心肌梗死(AMI)后恶性室性心律失常的价值.方法:回顾性分析2000年1月至2010年12月住院临床确诊的173例急性ST段抬高型心肌梗死患者的心电图(ECG)及其相关资料,根据ECG结果分为J波组(n=57)、ST段墓碑型抬高组(n=52,其中26例兼有J波出现)和通常组(n=90),J波组、ST段墓碑型抬高组分别与通常组比较QTd、JTd及恶性室性心律失常的发生率.结果:J波组、ST段墓碑型抬高组的QTd、JTd分别为(75.1+22.0)ms、(72.9±23.9)ms和(71.4±21.3)ms、(69.0±25.0),均明显高于通常组的(59.0±17.9)ms和(53.3±18.4)ms,P均＜0.01;J波组、ST段墓碑型抬高组的恶性室性心律失常的发生率分别为31.6％、28.8％,均明显高于通常组的10％,P均＜0.01.结论:心电图心室复极异常指标J波、ST段抬高、QTd、JTd延长均可作为AMI患者恶性室性心律失常的预测指标.     

急性心肌梗塞早期QT离散度分析

本文回顾分析了60例急性心肌梗塞（AMI）患者,患者在发病24 h内就诊,并描记首次心电图,分为有严重室性心律失常组和无室性心律失常组。发现两组QT离散度（QTd）和心率校正的QT离散度,（QTcd）均有显著的差异。而不同部位的急性心肌梗塞分组比较QTd和QTcd未显示明显的差异。     

Dispersion of Ventricular Refractoriness in Experimental Myocardial Infarction: Effect of Sotalol

Dispersion of refractoriness may contribute to the propensity for reentrant arrhythmias. This study was performed to assess the effect of sotalol on the dispersion of refractoriness in experimental myocardial infarction. In 9 mongrel dogs, 14 days after induction of myocardial infarction by an occlusion reperfusion technique, programmed ventricular stimulation and epicardial mapping were performed before and during (3 mg/kg + 0.5 mg/kg per hour) sotalol administration. To assess the spatial distribution of refractoriness, ventricular fibrillation (VF) intervals were analyzed. The rationale for this method is that, during VF, when multiple reentrant wavelets are present, cells are excited as soon as they recover from previous activation. The coefficient of variation (standard deviation × 100) served as an index of spatial distribution of refractoriness. Results : VF was induced before sotalol in 7 dogs and in 5 of 7 during sotalol administration. The mean value of the index VF intervals decreased from 19.8 ± 2.3 at baseline to 15.8 ± 2.6 during sotalol (P = 0.011), indicating a more homogeneous distribution of refractoriness. Thus, the antiarrhythmic effects of sotalol may be mediated by its action on the dispersion of refractoriness.