健康人Tp—e时间与Q—T间期比值的研究

目的观察健康人T波峰-末时间（Tp—e时间）与Q—T间期的比值（Tp—e／Q—T）,为临床Tp—e／Q—T的研究提供正常参考依据。方法选取1012例健康体检者,其12导联心电图T波在Ⅱ、V3、V4和V5直立,终末部清晰可辨,心率60～100次／min。分别测量Ⅱ、V3、V4和V5 Q—T间期、Q—TP间期,计算Tp—e时间、Tp—e／Q—T值。结果Tp—e／Q—T各导联总均值为022±0．03,95％可信区间0．16～0．28;V3、V。和V5Tp—e／Q—T总均值为022±0．03,95％可信区间0.16～0．28。当心率从60次／min至100次／min不等时,各导联间Tp—e／Q—T差异无统计学意义（P〉0．05）;各导联Tp—e／Q—T在不同性别和年龄间差异均无统计学意义（P〉0．05）;不同导联Tp—e／Q—T差异亦无统计学意义（P〉0.05）。结论得到了健康人Tp—e／Q—T的正常参考值。     

肥厚型心肌病患者发生室性心律失常的相关危险因素分析

目的探讨肥厚型心肌病（hypertrophic cardiomyopathy,HCM）患者室性心律失常发生的相关性因素及特点。方法回顾性分析95例经临床及超声心动图检查确诊的HCM患者的临床资料,并与80例无心脏病对照组进行比较。结果室性心动过速（室速）组与非室速组的晕厥发生率（61．74％vs11．76％,P〈0．05）、家族史（38．9％vs11．7％,P〈0．05）、Q-Tc间期[（448．83±28．22）msvs．（427．38±25．55）ms,P〈0．05]、T波峰-末（T—peak—end,Tp．e）间期[（108．33±6．85msvs（100．00±11．32）ms,P〈0．051、经心率校正后T波峰-末（Tp—ec）间期[（126．33±12．13）msvs（95．95±12．15）ms,P〈0．05]、射血分数（53．03％±14．31％眠71．00％±8．63％,P〈0．05）比较,差异有统计学意义。Logistic回归分析结果显示,Tp—e间期、Tp—ec间期、Q—T间期延长、左心室流出道梗vs与HCM恶性室性心律失常的发生相关。结论HCM患者的心肌结构排列紊乱和心电紊乱严重,易发生快速性心律失常。Tp—e间期、Tp—ec间期、Q—T间期延长、左心室流出道梗vs与恶性室性心律失常的发生关系密切。Tp—e间期、Tp—ec间期可能具有预测室性心律失常发生的价值。     

扩张型心肌病者T波峰-末间期及其离散度的检测

目的检测扩张型心肌病（DCM）者T波峰-末（1协）间期及Tpe离散度（Tped）与室性心律失常发生的相关性预测价值。方法对149例DCM者按是否伴有室性心律失常而分为室性心律失常组（A组）和非室性心律失常组（B组）。分别测量其入院后24h内首次心电图的R—R间距，Q—T间期，Qrp（Q为自QRS波群的起点至正向T波的顶点或负向的T波最低点的距离），并测算出T波顶．最至T波终点的距离，即Tpe（P—e=QT—QTp），以及Tped（即：最长Wpe与最短Tpe之差）。然后进行比较分析。结果在A组Tpe较B组明显延长（140．938±22．196ms〉93．833±25．91ms）。A组Tped也较B组明显延长（60．313±9．327ms〉34．083±12．866ms）。结论在DCM者中A组Tpe及Tped均较B组明显延长，表明A组跨壁复极离散度增大，与室性心律失常的发生有显著的相关性，可能具有预测室性心律失常发生的价值。     

急性心肌梗死患者T波峰-末间期与其离散度

目的探讨急性心肌梗死（AMI）者T波峰-末间期（Tpe）及Tpe离散度（Tped）与室性心律失常发生的相关性之预测价值。方法对82例ANI者按是否伴有室性心律失常,分为室性心律失常组（A组）和非室性心律失常组（B组）。分剐测量其入院24h内首次心电图的R—R间距、Q—T间期、Q—Tp、Tpe以及Tped,并进行分析。结果Tpe及TpedA组较B组明显延长,两组比较具有显著性及非常显著性差异（P〈0．05及0．01）。结论在AMI者中,A组ripe及Tped均较B组明显延长,具有统计学意义,有望成为预测室性心律失常及预后的临床指标。     

Tp—e时间及离散度对Brugada综合征患者预后的分析

目的探讨T波峰-末时间（Tp—e时间）及离散度与Brugada综合征患者预后的关系。方法采用动态心电图分析仪测量31例Brugada综合征患者的Tp—e时间及离散度。随访2～6年，每年2次，心脏事件为猝死幸存和（或）发生室性心动过速／心室颤动。结果无症状者发生心脏事件的Tp—e时间及离散度分别为（116．00±8．94）ms、（3300±1150）ms；未发生心脏事件者分别为（8666±1000）ms、（22．00±6．30）ms，差异有显著统计学意义（均P〈0．01）。有症状者再发生心脏事件的Tp—e时间及离散度分别为（108．50±10．69）ms、（3420±1060）ms；未发生心脏事件者分别为（85．45±9．34）ms、（18．10±12．60）ms，差异有显著统计学意义（均P〈0．01）。Tp—e时间及其离散度预测心脏事件发生的ROC曲线下面积分别为0947、0703。结论Tp—e时间及离散度可作为一种无创手段用于预测Brugada综合征患者发生心脏事件。     

冠心病患者Tp-e间期与复杂性室性心律失常关系的研究

目的观察不同方法（Tmax法、T均法和TV3法）测得的冠心病患者Tp—e间期差异以及其与复杂性室性心律失常的关系。方法315例患者的12导联心电图通过计算机图像软件处理获得Tp—e间期资料,同时行动态心电图检查并按检查结果分组：A组,冠心病单纯室性期前收缩频发组（室性期前收缩≥30次／h）;B组,冠心病复杂性室性期前收缩组（多形性、多源性、R在T上、连发室性期前收缩,可合并室性逸搏）;C组,冠心病室性心动过速、心室扑动及颤动组;D组．冠心病对照组（无明显快速性室性心律失常,室性期前收缩〈30次／h,且无其他室性心律失常）;E组．正常对照组。评价上述3种不同方法测得的Tp-e间期对室性心律失常的预测能力并将Tp—e间期与Q—T间期离散度（Q—Td）进行比较。结果B、C组的Tp-e问期不仅显著大于正常对照组,也显著大于冠心病对照组（P〈0．05）。而A组Tp—e间期大于对照组,但差异无统计学意义（P〉0.05）。结论Tp—e间期对复杂性室性心律失常有预测价值。且优于Q-Td。     

急性心肌梗死Tp-e时间与恶性室性，心律失常关系的研究

目的 研究急性心肌梗死患者T波峰-末时间（Tp—e时间）与恶性心律失常的关系。方法将62例急性心肌梗死患者分为恶性室性心律失常组（观察组,n=17）和非恶性室性心律失常组（对照组,n=45）。比较两组各导联和12导联平均Tp—e时间、经心率校正的Tp—e（Tp-ec）时间。结果与对照组比较,观察组各导联和12导联平均Tp—e时间及Tp—ec显著延长,差异有显著或非常显著性意义（P〈0．05或0．01）。结论Tp—e时间可以作为预测急性心肌梗死恶性室性心律失常的指标。     

Q—T离散度与室性心动过速的关系探讨

探讨Q—T离散度(Q—Td)与室性心律失常的关系,观察室性心动过速患者(n=22)体表DCG Q—Td.发现室速发作前3天内Q—Td大,Q—Td值室速组为88.0±24.0ms,对照组(n=30)为20.2±12.0ms,两组有非常显著差异(P<0.001),认为Q—Td增大可作为预测室速的发生。     

心向量图与心电图的Q—T间期离散度比较分析

目的应用心向量图和12导联心电图对比分析Q—T间期离散度（Q—Td）。方法使用Metronics心电工作站分别对确诊的心肌梗死组100例（其中心电图ST—T正常和异常者各50例）、正常组100例、对照组50例（心电图ST—T均异常）行同步12导联心电图（D1）、心向量图（正交心电图，D2）和时间心向量图（D3）检测，并测定和比较Q—Td。结果心肌梗死组中ST-T异常者D1（27．49±25．32）ms，明显大于D2（7．35±13．01）ms和D3（1．56±4．08）ms（均P〈0．01）：正常组D1（15．72±15-71）ms，明显大于D2（1．22±4．7）ms、D3（1．60±4．92）ms（均P〈0．01）；对照组D1（46．37±23．80）ms，亦明显大于D2（16．88±20．56）ms和D3f4．334-9，47）ms（均P〈0．01）。心肌梗死组无ST-T改变者D2、D3与对照组比较，差异无统计学意义（均P〉0．05）。而D1则有统计学意义（P〈0．05）。结论测量方法可影响Q-Td的大小，12导联心电图Q—Td的增大与ST—T改变有关。     

T波峰末间期

T波峰末间期（Tpeak—Tendinterval，Tp—Te间期）是指心电图T波顶点至T波终末的时间间期，心脏电生理关于离子通道、心室跨壁离散度的研究揭示了Tp—Te间期的发生机制，心电图参数Tp-Te间期研究的最新进展显示了其对心律失常发生风险的评估有重要临床价值。     

Relation between left ventricular geometry and transmural dispersion of repolarization

Studies have shown an association between left ventricular (LV) geometry and complex ventricular ectopic activity. Increased transmural dispersion of repolarization (TDR), which correlates to the interval from the peak to the end of the T wave (Tpe) on the surface electrocardiogram, is linked to ventricular tachyarrhythmias. The relation between LV geometry and TDR is unknown. The mean Tpe interval, measured from leads V(1) to V(3) of the surface electrocardiogram, was assessed in 300 patients (50% men) who had normal LV systolic function and QRS duration and were categorized into 3 equal groups, which were matched by age and gender, according to echocardiographically determined LV geometry (normal structure, concentric remodeling, and LV hypertrophy). The Tpe interval was corrected for the QT interval using Tpe/QTc and was compared among the 3 groups. Compared with those who had normal LV structure, the Tpe interval was significantly prolonged in those who had LV hypertrophy and significantly shortened in those who had concentric remodeling (p = <0.0001 for the 2 comparisons). Correcting for the QT interval using Tpe/QTc yielded similar results. Thus, TDR was increased in patients who had LV hypertrophy but decreased in concentric remodeling compared with those who had normal cardiac structure. Although LV hypertrophy represents a maladaptive geometric process that results in an unfavorable electrical substrate, concentric remodeling may represent a structural adaptation that has a more favorable electrical milieu.     

Exercise-induced repolarization changes in patients with stable coronary artery disease

Exercise is a classic trigger of ventricular arrhythmias in the setting of coronary artery disease (CAD). The aim of this study was to examine the changes of novel indexes of repolarization in patients with stable CAD who underwent exercise stress testing. Sixty-seven consecutive patients (mean age 62 ± 9 years, 60 men) who underwent treadmill exercise stress testing according to the Bruce protocol and completed the test without evidence of ischemia were enrolled. Baseline clinical and demographic characteristics were recorded, and indexes of repolarization such as corrected QT (QTc) interval, T peak-to-end (Tpe) interval, and Tpe/QT ratio were assessed at baseline and at peak exercise. A similar group of control subjects without CAD (n = 68, mean age 60 ± 11 years, 52 men) were also studied. All participants successfully completed the test. In the patient group, the QTc interval significantly increased from baseline to peak exercise (median 385 ms [25th percentile 357 ms, 75th percentile 407 ms] vs 418 ms [381 ms, 447 ms], p <0.001). The Tpe interval and the Tpe/QT ratio were also significantly increased at peak exercise (42 ms [36 ms, 60 ms] vs 78 ms [60 ms, 84 ms], p <0.001; and 0.17 [0.14, 0.22] vs 0.21 [0.16, 0.25], p = 0.015). In the control group, the QTc interval did not change significantly, the Tpe interval decreased at peak exercise (62 ms [41 ms, 80 ms] vs 48 ms [40 ms, 78 ms], p = 0.05), and the Tpe/QT ratio did not show a significant change (0.18 [0.12, 0.22] vs 0.16 [1.14, 0.21], p = 0.39). In patients with stable CAD and normal treadmill exercise stress test results, the QTc interval, the Tpe interval, and the Tpe/QT ratio increased during exercise. In conclusion, it is reasonable to assume that despite the absence of inducible ischemia, the spatial dispersion of repolarization is increased during exercise, exposing these patients to increased arrhythmic risk.     

Ibutilide and novel indexes of ventricular repolarization in persistent atrial fibrillation patients

AIM: To examine the effect of ibutilide on novel indexes of repolarization in patients with persistent atrial fibrillation (AF). METHODS: We studied consecutive patients scheduled for elective electrical cardioversion. Intravenous ibutilide (1+1mg) was administered before the electrical cardioversion while close electrocardiographic (ECG) monitoring was performed. ECG indexes such as corrected QT interval (QTc), the interval from the peak until the end of T wave (Tpe), and the Tpe/QT ratio were measured before ibutilide infusion and 10 min after the end of infusion. RESULTS: The final study population consisted of 20 patients (mean age: 67.1±9.9 years, 10 men). Six patients were cardioverted pharmacologically and did not proceed to electrical cardioversion. Two patientsdeveloped short non-sustained episodes of torsades de pointes ventricular tachycardia. All but one of the aforementioned ECG indexes increased significantly after ibutilide administration. In specific, the QTc interval increased from 442 ± 29 to 471 ± 37 ms (P=0.037), the Tpe interval in precordial leads from 96 ms (range 80-108 ms) to 101 ms (range 91-119 ms) (P=0.021), the Tpe interval in lead Ⅱ from 79 ms (range 70-88 ms) to 100 ms (range 87-104 ms) (P<0.001), the Tpe/QT ratio in precordial leads from 0.23 ms (range 0.18-0.26 ms) to 0.26 ms (range 0.23-0.28 ms) (P=0.028), and the Tpe interval dispersion from 25 ms (range 23-30 ms) to 35 ms (range 27-39 ms) (P=0.012). However, the Tpe/QT ratio in lead II did not change significantly. CONCLUSION: Ibutilide increases the duration and dispersion of ventricular repolarization. The prognostic value of Tpe and Tpe/QT in the setting of drug-induced proarrhythmia needs further study.     

Gender and age effects on ventricular repolarization abnormality in Japanese general carriers of a G643S common single nucleotide polymorphism for the KCNQ1 gene.

BACKGROUND: The KCNQ1 single nucleotide polymorphism (SNP), G643S, is known to be associated with secondary long QT syndrome (LQTS) and to cause a mild reduction in KCNQ1 current. However, the precise incidence and its association with QT intervals remain unknown in the greater cohort of the population in Japan. METHODS AND RESULTS: The genotype was screened at codon 643 of KCNQ1 in 992 residents of a farming community. Eighty-eight individuals (female/male =52/36, 8.9%) were found to have a heterozygous G643S SNP. Matching both gender and age, we randomly selected 243 control (G643G) cases and compared the electrocardiogram parameters in both groups; QT, QTf (QT corrected by Fridericia's formula) intervals, the peak and the end of the T wave (Tpe) interval, and the Tpe/QT ratio. The latter 2 reflect the transmural dispersion of ventricular repolarization (TDR). In G643S carriers, both Tpe and Tpe/QT were significantly longer than in non-carriers, without significant QT prolongation. Both genders showed a tendency for an increase in QTf with aging. In females, both Tpe and Tpe/QT showed a similar significant increase with age, which was not observed in males. CONCLUSIONS: In elderly females, G643S might be an independent risk factor for secondary LQTS by causing a greater TDR.     

Effects of atorvastatin on ventricular late potentials and repolarization dispersion in patients with hypercholesterolemia

Emerging evidence suggests that statins have a favorable impact on the reduction of arrhythmia events and sudden cardiac death in patients with structural heart disease. We aimed to investigate the possibly and directly favorable effects of statins on ventricular late potentials, QT dispersion, and transmural dispersion of repolarization attained by analyzing clinical electrocardiography (ECG) risk stratification parameters in patients with hypercholesterolemia without structural heart disease. In total, 82 patients (45 females; mean age, 62 +/- 10 years) with hypercholesterolemia were enrolled in this prospective study to examine the effects of statin therapy (atorvastatin 10 mg/day for 3 months) on ECG risk stratification parameters. Surface 12-lead ECG and signal-average ECG (SAECG) were recorded before and after statin treatment. The SAECG parameters, QT dispersion, Bazett-corrected QT (QTc) dispersion, T wave peak-to-end interval (Tpe), and percentage of Tpe/QT interval were calculated and compared before and after statin therapy. Twelve-lead ambulatory 24-hour ECGs were recorded in 12 patients. The results demonstrated that after statin therapy for 3 months, serum levels of total cholesterol and low-density lipoprotein cholesterol were significantly reduced (both p values < 0.001). However, neither significant changes of each SAECG parameter nor the frequency of late potentials were demonstrated after atorvastatin therapy. In addition, no significant changes in QT dispersion, QTc dispersion, Tpe, or Tpe/QT were found. However, 24-hour ambulatory ECG revealed a flattening effect of circadian variation of QTc dispersion after atorvastatin therapy. In conclusion, the favorable antiarrhythmia effect of atorvastatin (10 mg/day) therapy cannot be directly reflected by analyzing these noninvasive ECG risk stratification parameters in low-risk patients with hypercholesterolemia.     

高血压左室构型与跨室壁复极离散度关系的研究

目的探讨高血压患者左室构型与跨室壁复极离散度的关系。方法根据超声心动图所测指标将高血压患者分为4组,利用体表心电图计算出T波峰-末间期（Tpeak—Tend interval,Tpe）和Tpe／QT。结果①向心性肥厚患者Tpe值（ms）与正常构型组相比增高（男性：109．2±12-3和80．3±12．6,P〈0．05;女性：104．6±13．2和82．3±14．1,P〈0．05）;Tpe／QT值也有相同的结果（男性：0．26±0．10和0．19±0．03,P〈0．05;女性：0．25±0．05和0．20±0．02,P〈0．05）。②离心性肥厚患者Tpe值（ms）与正常构型组相比增高（男性：114．2±14．3和80．3±12．6．P〈0．05;女性：110．3±12．5和82．3±14．1,P〈0．05）;Tpe／QT值也有相同的结果（男性：0．29±0．09和0．19±0．03,P〈0．05;女性：0．28±0．10和0．20±0．02,P〈0．05）。③向心性重构组与正常构型组对比,Toe值（ms）差异无统计学意义（男性：79．9±11．6和80．3±12．6,P〉0．05;女性：80．1±10．5和82．3±14．1,P〉0．05）;Tpe／QT值也有相同的结果（男性：0．21±0．08和0．19±0．03,P〉0．05;女性：0．19±0．03和0．20±0．02,P〉0．05）。结论高血压病患者左室构型异常的程度与Tpe和Tpe／QT值增高相一致。推测向心性肥厚型和离心性肥厚型高血压患者易发生房室性心律失常。     

Increased regional and transmyocardial dispersion of ventricular repolarization in end-stage renal disease

BACKGROUND: Approximately half of patients with end-stage renal disease die because of cardiac disease, and ventricular arrhythmias are the common terminal events. Increased dispersion of the repolarization phase of the myocardial action potential can predispose patients to ventricular tachycardia and fibrillation causing cardiac death. OBJECTIVE: To determine the existence of increased regional and transmyocardial dispersion of ventricular repolarization in end-stage renal disease. STUDY DESIGN: Case-control prospective study. PATIENTS AND METHODS: The QT dispersion and the interval between the peak of the T wave (Tp) and the end of the T wave (Te) on a surface electrocardiogram represent regional and transmyocardial dispersion in ventricular repolarization, respectively. The prehemodialysis QT dispersions and Tp-Te intervals of 94 consecutive patients with end-stage renal disease were determined and compared with those of age- and sex-matched healthy controls. RESULTS: Both the QT and the QTc dispersion were significantly higher in the end-stage renal disease group than in the control group (QT dispersion 46 +/- 17 ms [mean +/- SD] versus 26 +/- 16 ms, P < 0.001; QTc dispersion 51 +/- 20 ms versus 30 +/- 20 ms, P < 0.001). Similarly, both the corrected average Tp-Te and the corrected maximum Tp-Te intervals were significantly higher in the end-stage renal disease group than in the control group (corrected average Tp-Te interval 99 +/- 19 ms versus 87 +/- 19 ms, P = 0.023; corrected maximum Tp-Te interval 114 +/- 23 ms versus 103 +/- 23 ms, P = 0.023). CONCLUSIONS: Increased regional and transmyocardial dispersion of ventricular repolarization in end-stage renal disease was demonstrated. This increased dispersion may be a contributory factor in the high cardiac mortality in patients with end-stage renal disease.     

QT dispersion in amyloidosis due to familial Mediterranean fever

Cardiac amyloid deposition in FMF may cause increased QT dispersion (QTd), a marker for cardiac arrhythmias. The aim of this study was to further evaluate repolarization dispersion in familial Mediterranean fever (FMF) with amyloidosis. Findings on 12-lead electrocardiography were compared between 18 patients with FMF-amyloidosis and 18 age- and sex-matched control subjects. Repolarization and dispersion parameters were computed with designated computer software, and results of the 5 beats were subsequently averaged. There were no statistically significant differences between the groups as to average corrected QT interval length, average QTd interval, average QT corrected dispersion, or QT dispersion ratio. JT dispersion and JT corrected dispersion were also similar in both groups. In conclusion, patients with FMF-amyloidosis seem to have QT and JT dispersion parameters similar to those of healthy subjects. Future research and longer follow-ups should be conducted in order to evaluate the prognostic importance of repolarization dispersion parameters in amyloidosis of FMF.     

Changes of the T-wave amplitude and angle: an early marker of altered ventricular repolarization in hypertension

BACKGROUND: The heterogeneity of ventricular repolarization is an important proarrhythmic factor. QT dispersion has been proposed to reflect the inhomogeneity of ventricular repolarization, but a poor reproducibility limits its clinical applicability. Reliable noninvasive methods to quantify abnormalities in ventricular repolarization are still lacking. The T-loop morphology analysis is a novel method aimed at quantifying ventricular repolarization. HYPOTHESIS: To test the ability of the T-loop morphology analysis to discriminate between hypertensive patients and healthy subjects, 105 hypertensive patients (mean age 63.6 +/- 12.3 years) and 110 healthy controls (mean age 49.7 +/- 14.3 years) were evaluated. METHODS: The maximum QT interval (QT maximum), the minimum QT interval (QT minimum), and their difference (QT dispersion) were calculated from a digitally recorded 12-lead electrocardiogram (ECG) in both study groups. X, Y, and Z leads were reconstructed from the 12-lead ECG, and the amplitude of the maximum T vector (T amplitude) and the angle between the maximum T vector and X axis (T angle) were calculated from the projection of the T loop in the frontal plane. RESULTS: T amplitude (p < 0.001), T angle (p = 0.05), and QT dispersion (p = 0.04) were significantly different between hypertensive patients and controls, while QT maximum (p = 0.14) and QT minimum (p = 0.35) did not differ between the groups. T amplitude was the only marker which differed between hypertensive patients without ECG criteria for left ventricular hypertrophy and controls (p = 0.002). CONCLUSIONS: T-loop features and particularly T amplitude are significantly different between hypertensive patients and healthy controls and may serve as early markers of repolarization abnormalities in a hypertensive population.     

不同部位起搏对体表心电图有关参数的影响

目的观察心脏不同部位起搏对体表心电图有关参数的影响。方法 10只健康猪,分别在右房(RA)起搏、右室心尖部心内膜起搏(RVEndo)及左室心外膜(LVEpi)起搏,记录并测量不同部位起搏后体表心电图12个导联的QRS波时限、QT间期、JT间期和T波峰-末间期(Tpe),计算Tpe平均值(TpeAVE)、Tpe最大值(TpeMAX)。结果 LVEpi起搏时QT间期、JT间期大于RA及RVEndo起搏时(P均<0.05);LVEpi起搏时TpeAVE,TpeMAX大于RA及RVEndo起搏时(P均<0.05),而RA与RVEndo起搏时此两指标无差异。结论 LVEpi起搏可能会增加健康心室整体复极离散。