2型糖尿病患者心电图QT间期的变化及卡托普利对其影响

目的　探讨 2型糖尿病患者心电图QT间期的变化及卡托普利对其影响。方法　对 189例糖尿病患者心电图QT间期进行测量 ,并按Bazett公式进行校正 ,取其校正的QT间期QTc与 12 0例正常人进行对照。给糖尿病患者卡托普利治疗 ,观察治疗 1、2、3、6个月后QTc间期的变化。结果　正常人QTc间期 ,男性 396± 1.7ms ,女性 418± 2 .3ms。糖尿病患者QTc ,男性 40 7± 1.9ms、女性 42 7± 2 .2ms。糖尿病患者卡托普利治疗 3、6个月后QTc间期缩短 ,分别为 :男性40 3± 2 .1ms、40 2± 1.6ms ,女性 413± 2 .3ms、412± 1.9ms。与治疗前相比具有显著性差异。结论　 2型糖尿病患者QTc间期延长 ,卡托普利可使延长的QTc间期缩短。提示卡托普利有助于防治糖尿病心血管并发症     

肥厚型非梗阻心肌病患者Tp-Te间期和Tp-Te/QT比率的临床分析

目的:肥厚型非梗阻心肌病患者Tp-Te间期和Tp-Te/QT比率的临床意义.方法:收集肥厚型非梗阻心肌病患者60例,其中室间隔和左室后壁比值1.3～1.5组(组1)27例、比值≥1.5组(组2)33例,并与相匹配的健康人60例作为对照,分别测量并计算Tp-Te间期和Tp-Te/QT比率.结果:肥厚型非梗阻心肌病患者Tp-Te间期和Tp-Te/QT比率分别为(132.67±12.74)ms,0.34±0.04,时照组(80.67±12.74)ms,0.22±0.03,两组比较有显著统计学意义(均P<0.05).Tp-Te间期在组1为(117.41±11.23)ms、组2为(145.15±14.82)ms,两组比较有统计学意义(P<0.05),两组间Tp-Te/QT比率比较有统计学意义(0.38±0.02vs 0.31±0.02)(P<0.05).结论:肥厚型非梗阻心肌病患者Tp-Te间期和Tp-Te/QT比率显著延长,Tp-Te间期与左室厚度相关.     

冠心病伴室性心律失常与左室射血分数及QT离散度的关系

目的:探讨冠心病(CHD)伴室性心律失常与左室射血分数(LVEF)及QT离散度(QTd)的关系。方法:测量和分析56例CHD伴室性心律失常患者(CHD组)和53例正常人(对照组)的LVEF值及心电图最大QT间期(QTmax),最小QT间期(QTmin)。结果:CHD组的LVEF值和QTd分别为:(40.36±6.85)ms和(65.98±16.86)ms;对照组的LVEF值和QTd分别为:(59.68±4.16)ms和(33.05±13.23)ms。CHD组与对照组之间比较差异具有显著性,P<0.01。结论:CHD伴室性心律失常与LVEF及QTd密切相关,LVEF和QTd可作为预测CHD伴室性心律失常的可靠指标。     

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     

心肌梗死经皮冠状动脉介入治疗前后Tp-e间期、Tp-e/QT变化及预测价值

目的：探讨急性ST段抬高心肌梗死患者经皮冠状动脉介入治疗前后QT间期、Tp-e和Tp-e/QT指标变化及预测恶性心律失常的价值。方法：急性ST段抬高心肌梗死患者(观察组)54例，12 h内行经皮冠状动脉介入术治疗，测算梗死相关导联和非相关导联校正的QT间期、校正的Tp-e、Tp-e/QT比值，随访1 a内恶性心律失常发生情况。同期健康体检心电图正常者60例为对照组，并与观察组进行相关指标比较。结果：(1)观察组心肌梗死12 h内校正的QT间期较对照组明显延长(P＜0.05)，但经皮冠状动脉介入治疗术后恢复正常(P＜0.05)；梗死相关导联12 h内校正的Tp-e间期和Tp-e/QT比值较非梗死导联和对照组均明显延长(P＜0.05),经皮冠状动脉介入治疗术后逐渐恢复正常(P＜0.05)，但与对照组比较差异有统计学意义(P＜0.05)。(2)观察组以校正的QT间期440 ms为节点，发生恶性心律失常差异无统计学意义(P＞0.05)，观察组心肌梗死12 h内校正的Tp-e 100ms和Tp-e/QT比值0.25为节点，发生恶性心律失常差异有统计学意义(P＜0.05)。结论：校正的Tp-e，Tp-e/QT比值可能是预测急性心肌梗死后恶性心律失常的新指标。     

心脏再同步化治疗不同起搏模式对终末期心力衰竭心室复极的影响

目的探讨心脏再同步化治疗(cardiac resynchronization therapy,CRT)不同起搏模式对终末期心力衰竭患者心室复极的影响。方法回顾分析51例接受CRT的终末期心力衰竭患者的心电图资料。记录患者自主心律、右室心内膜起搏(RV-endo-P)、左室心外膜起搏(LV-epi-P)及优化后双室起搏(Bi V-P)心电图。测量QRS波时限,QT间期、Tp-e(T波顶点到T波结束)间期,并计算QTc间期(校正后QT间期)、QT离散度(QT-d)及Tp-e离散度。并将各起搏模式心电图数据与患者自主心律进行比较。结果相对患者自主心律,LV-epi-P可显著延长患者QRS波时限、QTc间期及Tp-e间期,并增加QT-d及Tp-e离散度。QRS波时限平均延长23.31 ms(95%CI:16.64~29.98 ms,P0.01);QTc间期平均延长32.35 ms(95%CI:18.49~46.22 ms,P0.01);Tp-e间期平均延长21.98 ms(95%CI:13.09~30.87 ms,P0.01);QT-d平均增加27.96 ms(95%CI:19.14~36.78 ms,P0.01);Tp-e离散度平均增加26.06 ms(95%CI:18.35~33.77 ms,P0.01)。Bi V-P可明显缩短QRS波时限,RV-endo-P可显著延长QRS波时限,差异均有统计学意义(P0.01);Bi V-P及RV-endo-P虽有延长QTc间期及减小QT-d、Tp-e间期、Tp-e离散度的趋势,但差异均无统计学意义(P0.05)。结论 LV-epi-P可使终末期心力衰竭患者心室跨壁复极离散度增大,具有潜在的心律失常事件发生风险。建议植入心脏再同步心脏复律除颤器预防恶性室性心律失常致心源性猝死的发生。     

胺碘酮治疗对50例心律失常QT间期离散度的影响

目的:研究胺碘酮治疗心律失常对QT间期及QT间期离散度(QTd)的影响.方法:随机选取心律失常患者50例,予以胺碘酮治疗6周,比较治疗前后心律失常的疗效及QT间期与QTd的变化.结果:治疗后心律失常均明显减少,有效率85.2%,QTd明显缩短,由(61.03±9.20)ms减至(32.8±14.1)ms(P<0.01).结论:胺碘酮能有效减少恶性心律失常发生,而且使患者QTd明显缩小.     

右心室心尖部与流出道间隔部起搏对QRS波时限、QT间期及Tp-e间期的影响

目的观察右心室心尖部(RVA)与右心室流出道间隔部(RVOT)起搏对患者体表心电图QRS时限、QT间期及Tp-e间期的影响。方法选取因阵发性室上性心动过速在南京市鼓楼医院行射频消融的患者18例,术中将心室电极分别放置于右心室流出道间隔部及右心室心尖部,给予S1S2刺激,并测量S2刺激后体表心电图的QRS间期、QT间期和Tp-e间期。结果电生理检查结果显示:同RVA起搏比较,RVOT起搏后QRS时限明显缩短[(131.31±10.00)msvs.(156.40±13.16)ms,P<0.001],QT间期[(334.62±11.75)msvs.(351.09±20.13)ms,P<0.01]及Tp-e间期[(71.97±13.03)msvs.(83.48±14.81)ms,P<0.05)]也明显缩短,其差异均具有统计学意义。结论同心尖部起搏比较,右心室流出道间隔部起搏对QRS波时限、QT间期及Tp-e间期有明显的影响。     

扩张型心肌病患者T波峰末间期的测量及其与正常人群的比较

目的对扩张型心肌病患者的T波峰末间期进行科学规范的测量,并将其与正常人群进行比较。方法回顾性分析2010年1月至2011年6月在中国医学科学院阜外医院接受心脏再同步治疗的扩张型心肌病患者病例资料,选择其中33例术前心电图资料完整者作为观察组,对其术前自身心律的心电图进行分析。从南京医科大学附属逸夫医院体检中心心电图室导出2016年9月检查的40份正常人心电图,将这40名正常人作为对照组进行研究。依次测量12个导联的T波波峰到T波终末的时间间期,最终取12导联中数值最大的T波波峰到T波终末的时间间期作为某一个体的T波峰末间期。QT间期也定义为12个导联中QRS波起始到T波终末时间间期的最大值。比较2组差异。结果观察组33例患者中,29例(87.9%)患者T波峰末间期在胸前导联测得。与对照组相比,观察组的T波峰末间期更长[(119.7±23.6)ms vs(94.5±16.3)ms,t=5.368,P=0.000],T波峰末间期离散度更大[(45.2±18.2)ms vs(30.0±17.7)ms,t=3.593,P=0.001],但是T波峰末间期/QT间期比值在2组间没有差异(0.26±0.04 vs 0.25±0.04,t=1.350,P=0.181)。结论无论在扩张型心肌病患者中还是在正常人中,绝大多数研究对象可以在胸前导联准确测量到T波峰末间期。与正常人群相比,扩张型心肌病患者心室跨壁复极离散度更大。     

血液透析患者透析前后QT间期及QT离散度变化的临床意义

目的:探讨血液透析对患者QT间期和QT离散度(QTd)的影响.方法:对58例维持性血液透析(MHD)患者行超声心动检查并于透析前、后行心电图检查,测量计算QT间期、校正QT间期、QTd、校正QTd(QTcd).结果:与对照组相比,MHD患者左心室心肌重量指数(LVMI)显著增加(P＜0.01);两组间最大QT间期(QTmax)无明显差异,校正后MHD患者最大QT间期(QTcmax)延长(P＜0.05),QTd及QTcd均较对照组有极为明显的增加(均P＜0.01):透析后QTmax、QTcmax、QTd、QTcd均较透析前明显延长(均P＜0.05);MHD患者透析前QTd与其LVMI、透析前平均动脉压呈正相关(r分别为0.41和0.34,P＜0.05).结论:MHD患者LVMI增加,QTcmax、QTd、QTcd延长,透析后更加显著.血液透析后发生室性心律失常的危险性增大.     

QT dispersion is not increased in familial Mediterranean fever

Familial Mediterranean fever (FMF) is an autoimmune disease inherited as an autosomal recessive trait and is characterized by recurrent attacks of fever and sterile polyserositis. This study examined electrocardiographic ventricular repolarization parameters (QT interval and QT dispersion) in 38 FMF patients and 35 healthy controls. The QT interval was measured manually from the onset of QRS to the end of the T wave (return to the TP baseline). QT dispersion was defined as the difference between the maximum and minimum QT values, and corrected QT was calculated according to the Bazett formula. There were no significant differences between FMF patients and healthy control subjects in any parameter of ventricular repolarization; hence QT dispersion was not affected by FMF. Electrocardiographic assessment of QT interval and QT dispersion are, therefore, of little value for the evaluation of cardiac impairment and risk of arrhythmia in FMF patients.     

QT Duration and Dispersion in Patients with Anomalous Origins of Coronary Arteries

Background: Coronary artery anomalies have been reported to show various symptoms ranging from chest pain and dyspnea to cardio-respiratory arrest and sudden death. In this study, we attempted to assess the changes in QT interval duration and dispersion in anomalous origins of coronary arteries (AOCA).
Methods: Nineteen AOCA patients (mean age: 52 ± 11 years) and 30 healthy control subjects (mean age: 50 ± 12 years) were included in the study. Minimum and maximum corrected QT intervals, and corrected QT dispersion were calculated. The two groups were compared in terms of QT dispersion and QT duration.
Results: There was no difference between the two groups in terms of baseline demographic characteristics. Maximum corrected QT intervals (QTc max), minimum corrected QT intervals (QTc min), and corrected QT dispersion were higher in AOCA patients than controls (452 ± 38 vs 411 ± 25 ms [P = 0.0001], 402 ± 31 vs 383 ± 28 ms [P = 0.048], and 51 ± 30 vs 28 ± 12 ms [P = 0.001], respectively).
Conclusion: In the patients with anomalous origins of coronary arteries, QT dispersion that is an indicator of sudden cardiac death and arrhythmias frequency increased. QTc max, QTc min, and corrected QT dispersion are higher in patients with anomalous origin of the coronary artery than in control subjects.     

Assessment of QT interval duration and dispersion in athlete's heart

An athlete's heart is characterized by morphological and functional changes occurring as a consequence of regular physical exercise. We sought to determine if these physiological changes lead to ventricular repolarization abnormalities in trained athletes. Forty-four trained athletes and 35 sex- and age-matched healthy sedentary controls were included in the study. A 12-lead surface electrocardiogram (ECG) was obtained from all participants. Maximum QT (QTmax) and minimum QT (QTmin) interval durations, QT dispersion (QTd) and corrected QT dispersion (QTcd) were calculated for each ECG record. Heart rate, systolic and diastolic blood pressure values were found to be identical in both groups. QTmax and QTmin interval durations were not statistically different between the athletic and control groups. Similarly, QTd and QTcd did not differ significantly between the two groups. No association was observed between an athlete's heart and ventricular heterogeneity compared with healthy sedentary controls, despite physiological and structural changes.     

Clinical Significance of Increased QT Dispersion in the 12-Lead Standard ECG for Arrhythmia Risk Prediction in Dilated Cardiomyopathy

QT dispersion was determined from the 12-lead standard ECGs from 107 patients with idiopathic dilated Cardiomyopathy (IDC) and compared to QT dispersion measurements in 100 healthy age and sex matched controls. QT dispersion, rate corrected QT dispersion and adjusted QT_C dispersion were significantly greater in patients with IDC compared to controls. During a prospective follow-up of 13 ± 7 months, arrhythmic events, defined as sustained VT, VF, or sudden death, occurred in 12 (11%) of 107 study patients with IDC. QT dispersion was increased in patients with arrhythmic events compared to patients without arrhythmic events during follow-up (76 ± 17 vs 60 ± 26 ms; P = 0.03). Differences in QT_C dispersion and adjusted QT_C dispersion between patients with and without arrhythmic events, however, failed to reach statistical significance. Thus, although QT dispersion was increased in patients with IDC and arrhythmic events during follow-up, its clinical usefulness for risk stratification appears to be very limited due to the large overlap of QT dispersion among patients with and without arrhythmic events.     

Epinephrine-induced QT interval prolongation: a gene-specific paradoxical response in congenital long QT syndrome

OBJECTIVE: To determine the effect of epinephrine on the QT interval in patients with genotyped long QT syndrome (LQTS). PATIENTS AND METHODS: Between May 1999 and April 2001, 37 patients (24 females) with genotyped LQTS (19 LQT1, 15 LQT2, 3 LQT3, mean age, 27 years; range, 10-53 years) from 21 different kindreds and 27 (16 females) controls (mean age, 31 years; range, 13-45 years) were studied at baseline and during gradually increasing doses of intravenous epinephrine infusion (0.05, 0.1, 0.2, and 0.3 microg x k(-1) x min(-1)). The 12-lead electrocardiogram was monitored continuously, and heart rate, QT, and corrected QT interval (QTc) were measured during each study stage. RESULTS: There was no significant difference in resting heart rate or chronotropic response to epinephrine between LQTS patients and controls. The mean +/- SD baseline QTc was greater in LQTS patients (500+/-68 ms) than in controls (436+/-19 ms, P<.001). However, 9 (47%) of 19 KVLQT1-genotyped LQT1 patients had a nondiagnostic resting QTc (<460 milliseconds), whereas 11 (41%) of 27 controls had a resting QTc higher than 440 milliseconds. During epinephrine infusion, every LQT1 patient manifested prolongation of the QT interval (paradoxical response), whereas healthy controls and patients with either LQT2 or LQT3 tended to have shortened QT intervals (P<.001). The maximum mean +/- SD change in QT (AQT [epinephrine QT minus baseline QT]) was -5+/-47 ms (controls), +94+/-31 ms (LQT1), and -87+/-67 ms (LQT2 and LQT3 patients). Of 27 controls, 6 had lengthening of their QT intervals (AQT >30 milliseconds) during high-dose epinephrine. Low-dose epinephrine (0.05 microg x kg(-1) x min(-1)) completely discriminated LQT1 patients (AQT, +82+/-34 ms) from controls (AQT, -7+/-13 ms; P<.001). Epinephrine-triggered nonsustained ventricular tachycardia occurred in 2 patients with LQTS and in 1 control. CONCLUSIONS: Epinephrine-induced prolongation of the QT interval appears pathognomonic for LQT1. Low-dose epinephrine infusion distinguishes controls from patients with concealed LQT1 manifesting an equivocal QTc at rest. Thus, epinephrine provocation may help unmask some patients with concealed LQTS and strategically direct molecular genetic testing.     

Evaluation of PR, RR, QT Intervals and QT Dispersion Following Stellate Ganglion Block in Chronic Shoulder–Hand Pain Patients

Abstract: Right stellate ganglion block (SGB) can increase QT interval, rate‐corrected QT interval (QTc), QT dispersion (QTD), rate‐corrected QTD (QTcD), and RR interval while left SGB can decrease these intervals in healthy volunteers. No such studies have been conducted in patients with chronic pain, hence this study was designed to investigate the effects of left and right SGB on these variables in chronic shoulder–hand pain patients. In this study, 28 patients with chronic shoulder–hand pain of at least 6 months duration were given right or left SGB depending on the shoulder affected. A 12‐lead electrocardiogram (ECG) was recorded before the block, 30 minutes and 60 minutes after the block. PR interval, RR interval, QT interval were recorded in all 12 leads while QTc, QTD, and QTcD were calculated. Right SGB was performed in 21 patients. A significant decrease (P < 0.05) in PR interval and a significant increase (P < 0.05) in RR interval, QT interval, and QTc interval were observed. QTD showed a significant increase (P < 0.05) only at 30 minutes after right SGB. Left SGB was performed in seven patients. A significant decrease (P < 0.05) in QT interval was observed throughout the study period, while QTc showed a significant decrease (P < 0.05) only at 60 minutes after the block. We conclude that right SGB induces significant increase of QT interval, RR interval, QTc interval, QTD, and a significant decrease of PR interval while left SGB produces a significant decrease in QT and QTc intervals in patients with chronic shoulder–hand pain.     

Alteration of the QT rate dependence in anorexia nervosa

Myocardial repolarization has been evaluated in patients with anorexia nervosa (AN) with conflicting results. The authors postulated that dynamic alterations in QT interval adaptation could characterize these patients. This study compared QT dynamicity along RR intervals from 24-hour ECG data of patients with and without AN. Twenty-five patients (23 women) fulfilling the Diagnostic and Statistical Manual (DSM IV) criteria for AN were included in the study. All underwent 24-hour ECG Holter recordings, allowing QT and RR measurements, and heart rate variability (HRV) analysis in free-living conditions. A group of 25 sex- and age-matched healthy subjects served as controls. Compared with controls, AN patients presented with relative bradycardia, more particularly during night periods but neither mean QT nor corrected mean QT length (calculated using Bazett formula) over the 24 hours of monitoring differed. However, QT/RR slope was found significantly enhanced compared with normals (-2.00 +/- 0.53 vs - 1.42 +/- 0.40) (P = 0.006): QT length related to heart rate was found longer for a heart rate <55 beats/min in AN. Mean 24-hours QT length appears unaltered in AN in the absence of electrolytic disorders. However, the QT/RR relationship was enhanced reflecting the specific autonomic imbalance encountered in this population. The clinical implications of such findings need to be discussed since an equivalent enhancement of QT/RR slope has been described after myocardial infarction in patients presenting life-threatening ventricular arrhythmias.     

T wave peak-to-end interval and QT dispersion in acquired long QT syndrome: a new index for arrhythmogenicity

QT dispersion (QTD) on 12-lead ECGs has been proposed as a marker of malignant ventricular tachyarrhythmias, and increased QTD has been reported in long QT syndrome (LQTS). On the other hand, it has been demonstrated that transmural dispersion is associated with ventricular tachyarrhythmias in an experimental model. However, the precise type of QTD or transmural dispersion that contributes most to ventricular tachyarrhythmias in patients with LQTS remains unclear. We evaluated 27 patients with acquired LQTS. These patients were divided into two groups: group A (n =12), patients with polymorphic ventricular tachycardia [torsades de pointes (TdP)], and group B (n =15), patients without TdP. The QT intervals were corrected using Bazett's formula. QTD was measured as the difference between the maximum and the minimum QT intervals, and T wave peak-to-end interval divided by the QT interval (Tpe) in the V5 lead was measured as a new index. Both the corrected QTD (QTDc) and Tpe were significantly larger in group A than in group B. Logistic regression analysis revealed that a reliable predictor for TdP in the QT variables in these patients was not QTDc but Tpe. Cumulative frequency distributions revealed that a Tpe of 0.28 is a good cut-off point for TdP. Tpe did not correlate with the corrected maximum QT interval, whereas the QTDc did correlate with this parameter. In conclusion, Tpe may be the best predictor for TdP in patients with acquired LQTS.     

Alteration of the QT/RR Relationship in Patients with Idiopathic Ventricular Tachycardia

It has been shown that alterations in QT/RR relationship may be associated with arrhythmogenesis in several clinical settings. In the present study the QT/RR relationship was studied in 20 patients with idiopathic ventricular tachycardia (12 men and 8 women, aged 41±14 years) compared to 20 normal subjects (9 men and 11 women, aged 39 ± 13 years). All the patients were off any antiarrhythmic drugs and had no evidence of intraventricular conduction defects. The QT intervals and their preceding RR intervals were measured on electrocardiogram strips from 24-hour Holter tapes at hourly intervals. The differences in the maximum, minimum, and mean of either the QT interval or its corrected values between patients with idiopathic ventricular tachycardia and normal subjects were not statistically significant. There was a significant correlation between the QT and RR intervals in normal subjects (γ= 0.73 ± 0.12, P < 0.05) and in patients with idiopathic ventricular tachycardia (γ= 0.80 ± 0.10, P < 0.05). However, the linear regression line of the QT interval against the RR interval were significantly (P < 0.001) altered in patients with idiopathic ventricular tachycardia (QT = 0.24 + 0.18 RR) compared to normal subjects (QT = 0.27 ± 0.12 RR). We conclude that although there is no significant change in the QT interval and its corrected values, the QT/RR relationship is significantly altered in patients with idiopathic ventricular tachycardia as compared to normal subjects. This may be of importance in the pathogenesis of idiopathic ventricular tachycardia in these patients.