QTc, Tp-e Interval and Tp-e/QTc Ratio in Patients with Hypocalcemia-case Control Study

Abstract Background: To the best of our knowledge, there are studies related to QT and QTc interval in patients with hypocalcemia, but there are no studies evaluating T wave peak and end interval (Tp-e interval), Tp-e/QT and Tp-e/QTc ratios used to evaluate cardiac arrhythmia risk and ventricular repolarization changes rates. Objectives: Therefore, we aimed to investigate whether there is a change in Tp-e interval, Tp-e/QT and Tp-e/QTc ratios in patients with hypocalcemia. Methods: Retrospectively, 29 patients with hypocalcemia in the emergency department were included in the study. Twenty-nine patients with similar age and sex distribution were included in the study as the control group. All patients underwent 12-lead electrocardiography (ECG). In addition to routine measurements, Tp-e interval, Tp-e/QT and Tp-e/QTc ratios were measured on ECG. The study data were grouped as patients with and without hypocalcemia. Results: The mean age of the patients was 66.24 ± 4.95 years. QTc interval, Tp-e interval and Tp-e/QTc values were found to be significantly higher in patients with hypocalcemia (p <0.001 for each). QTc interval, Tp-e interval and Tp-e/QTc ratio showed a significant negative correlation with calcium levels. Conclusion: Tp-e interval and Tp-e/QTc ratios are significantly increased in patients with hypocalcemia compared to those without hypocalcemia and this can be used more effectively in the follow-up of cardiac fatal arrhythmias.

Acortamiento en la relación Tp-f/QTc tras angioplastia en pacientes con síndrome isquémico coronario agudo / Shortening in the Tp-e/QTc ratio after angioplasty in patients with acute coronary syndrome

Resumen Objetivo: La dispersión transmural de la repolarización ventricular (DTMRV) es un factor de riesgo para muerte en pacientes con síndrome isquémico coronario agudo (SICA). Con el objetivo de conocer el efecto de la realización de angioplastia sobre la DTMRV, se estudió la relación Tp-f/QTc en pacientes con SICA sometidos a angioplastia. Método: Se diseñó un estudio observacional, retrospectivo y descriptivo. Se incluyeron 150 pacientes (N = 150) con diagnóstico de SICA. Se valoró la relación Tp-f/QTc inicial y se evaluó su acortamiento posangioplastia. Como objetivo secundario, se comparó la asociación de dichos cambios en la relación Tp-f/QTc con la mortalidad cardiovascular y los eventos adversos cardiovasculares. Resultados: El promedio en la relación Tp-f/QTc inicial fue de 0.2529, mientras que posangioplastia fue de 0.2397. Por medio de prueba de rangos de Wilcoxon se evidenció un descenso significativo en la relación Tp-f/QTc posterior a la angioplastia, con un valor Z de −2.051 y una p < 0.04. En el análisis secundario se encontró que una Tp-f/QTc ≥ 0.29 posangioplastia es factor de riesgo para presentación de los siguientes eventos adversos: muerte intrahospitalaria (7.4 vs 0%; p < 0.003), nuevo SICA en seguimiento a 1 año (25.9 vs. 18.5%; p < 0.006) y reintervención en seguimiento a 1 año (29.6 vs. 15.0%; p < 0.002). Conclusiones: Existe un acortamiento significativo en la relación Tp-f/QTc posangioplastia en pacientes con SICA. Esta medida de la DTMRV puede servir como un predictor de muerte intrahospitalaria, eventos cardiovasculares y reintervención a 1 año en pacientes con SICA tratados con angioplastia.

Abstract Objective: Transmural Dispersion of Repolarization (TDR) is a Risk factor for Death in patients with Acute Coronary Syndrome (ACS). In order to know the effect of angioplasty on TDR, the Tp-e/QTc ratio was studied in patients with ACS undergoing angioplasty. Method: An observational, retrospective and descriptive study was designed. 150 patients (N = 150) with diagnosis of ACS were included. The initial Tp-e/QTc ratio was assessed and then its post-angioplasty shortening was evaluated. As a secondary objective, we compared the association of these Tp-e/QTc ratio changes with cardiovascular mortality and cardiovascular adverse events. Results: The average in the initial Tp-e/QTc ratio was 0.2529, while post-angioplasty was 0.2397. Through a Wilcoxon rage test, a significant decrease in the Tp-e/QTc ratio after angioplasty was observed, with a Z value of −2.051 and p < 0.04. In the secondary analysis, it was found that a Tp-e/QTc ≥ 0.29 post-angioplasty is a risk factor for presenting the following adverse events: in-hospital death (7.4 vs. 0%; p < 0.003), new ACS in 1-year follow-up (25.9 vs. 18.5%; p < 0.006), and reintervention in 1-year follow up (29.6 vs. 15%; p < 0.002). Conclusions: There is a significant shortening in the Tp-e/QTc ratio post-angioplasty in patients with ACS. This measure of TDR can serve as a predictor of in-hospital death, cardiovascular events and 1-year reintervention in patients with ACS treated initially by angioplasty.

Effect of CO2 pneumoperitoneum combined with position changes on stability of cardiac electrophysiology in gynecological laparoscopy / 实用医学杂志

Objective To observe the effect of CO2 pneumoperitoneum combined with position changes on the stability of cardiac electrophysiology in gynecological laparoscopy. Methods The gynecological laparoscopy was performed for 30 patients to undergo elective gynecological laparoscopy under general anesthesia ,with the pneumoperitoneum pressure of 12 mmHg and the Trendelenburg positionat 15° . The observations and analyses were done over the basic monitoring index and the QT interval (QT),T peak tend interval (Tp-e),heart rate corrected QT interval(QTc),QT dispersion(QTd),Tp-e/QT before anesthesia(T0),after anesthesia(T1),1 min after pneumoperitoneum (T2),30 min after pneumoperitoneum and head-down tilt (T3),30 min after deflation and supine position(T4). Results Compared with the time point of T0,QTd increased significantly at T1(P<0.05) and so it was with QT,QTc,QTd,Tp-e,Tp-e/QT at T2,T3,and T4(P<0.05). Compared with the time point of T2,QTc,QTd,Tp-e,Tp-e/QT significantly increased at T3(P < 0.05). Conclusions CO2 pneumoperitoneum combined with Trendelenburg position can prolong ventricular repolarization duration and destroy the stability of cardiac electrophysiology so it may increase the incidence of cardiovascular events.

Characteristics of deceleration capacity and Tp-e/QT value in different age groups of patients with diabetic autonomic neuropathy / 中国糖尿病杂志

Objective To investigate characteristics of deceleration capacity (DC) and Tp-e/QT value in different age groups of patients with diabetic autonomic neuropathy, and to analyze their influencing factors. Methods A total of 487 subjects were enrolled in this study, and divided into three groups:patients with diabetic autonomic neuropathy (DM+CAN group,n=287), normal glucose tolerance patients with diabetic autonomic neuropathy (CAN group,n=130) and healthy controls (NC group,n=150).Then the DM+CAN group were further divided into three subgroups according to age tertiles:the lowest tertile group (35.0~47.2 years old,n=91),the middle tertile group (47.3~59.6 years old,n=116)and the highest tertile group (59.7~72.0 years old,n=80).All subjects were underwent 24-hour dynamic electrocardiogram recordings.DC and Tp-e/QT values were calculated,and then the correlation between DC and Tp-e/QT with other indicators was analyzed. Results The levels of WC,SBP,BMI,FPG,HbA1c,FIns and HOMA-IR were higher in DM+CAN group than in CAN group and in NC group (P0.05).DC increased [(2.90±0.47) vs (4.22±0.41) vs (4.97±0.35) ms],and the Tp-e/QT decreased [(0.23±0.05) vs (0.18±0.03) vs (0.12±0.02)] from the highest tertile group to the lowest tertile group,(P<0.05 or P<0.01),and the pairwise comparisons were statistically significant (P<0.05 or P<0.01).Multiple stepwise regression analysis showed that age,DM duration,WC,FPG,HbA1c,complicated with hypertension and coronary heart disease (CHD) were risk factors for DC and Tp-e/QT values (P<0.05). Conclusion Together with the increased age,DC level is reduced and Tp-e/QT value increased in patients with diabetic autonomic neuropathy.Dynamic electrocardiogram should be considered in patients with advanced age,long DM duration,high level of WC,FPG,HbA1c,and complicated with hypertension and CHD,in order to prevent the occurrence of cardiovascular events effectively.

Association between Tpeak-Tend interval/ QT interval (Tp-e/QT ratio) and prognosis in patients with acute pulmonary embolism

Background: Risk stratification of patients with acute pulmonary embolism (PE) allows assessment of individual prognosis and guides therapeutic decision making. Several electrocardiographic (ECG) markers measuring the arrhythmogenic substrate(s) in ventricular myocardium are used to identify the high-risk patients with acute PE. However studies on Tp-e/QT ratio in patients with acute PE are lacking therefore the present study is aimed to evaluate the in hospital prognostic significance (death and in hospital adverse clinical events [ACE]) of Tp-e/QT ratio at admission in acute PE patients. Materials and methods: This was a retrospective study that included adult patients who had been diagnosed with acute PE and were treated at our hospital between January 2012 and March 2016. After considering inclusion and exclusion criteria, data was collected from eligible patients. All ECG recordings were digitalized and evaluated by a computer based program. Tp-e and QT intervals were measured from all precordial leads and mean value is calculated. Statistical analysis was performed using SPSS 17.0. Receiver operator characteristic (ROC) curves were computed for the Tp-e/QT ratio to assess the optimal cutoff values for predicting mortality and ACE. Univariate logistic regression analysis for the predictors of in hospital events (death and in hospital ACE) in the study population was done. The statistical significance was considered for a p-value <0.05. Results: A total of 48 patients were included in the study with mean age of 37.95 years (±13.86) and male: female ratio of 1.18:1. Patients with pulmonary embolism have mean Tp-e/QT ratio of 0.25 and the range of Tp-e/QT ratio was 0.18 to 0.29. In regression analysis, a Tp-e/QT ratio ≥0.26 increased the risk of death (P = 0.03) and a Tp-e/QT ratio ≥0.25 increased the risk of ACE (P = 0.01) significantly.

Effects of target-controlled infusion of propofol with different concentrations on ventricular repolarization after preoperative infusion of cefuroxime sodium in patients undergoing gynecologic opera-tion / 临床麻醉学杂志

Objective To investigate the effects of target-controlled confusion of propofol with different concentrations on ventricular repolarization after prophylactic infusion of cefuroxime sodium. Methods Sixty ASA physical status Ⅰ or Ⅱ female patients,aged 18-65 years,undergoing elective gynecological surgery were randomly divided into three groups:group P2 (n =20)with TCI 2 μg/ml, group P3 (n =1 9)with TCI 3 μg/ml and group P4 (n =20)with TCI 4 μg/ml.Firstly,they were re-hydrated;secondly,the patients in groups P2,P3 and P4 were intravenous infused with cefuroxime sodium 2.5 g (in 100 ml normal saline)and then target-controlled infused of propofol 2 μg/ml,3μg/ml and 4 μg/ml in target plasma concentration,respectively.At three pionts of time:after rehy-dration before intravenous antibiotics (T0 ),after intravenous antibiotics before TCI of propofol (T1 ), after TCI of propofol (T2 ),QT interval,QTc interval,Tp-e interval were measured and recorded, respectively.Results Compared with T0 ,QTc [(469.9 ± 34.0)ms vs.(451.2 ± 24.9)ms],Tp-e [(107±25)ms vs.(94±20)ms]and Tp-e/QT (0.260±0.058 vs.0.236±0.043)in group P4 were sig-nificantly prolonged at T1 (P < 0.05 ).Compared with T1 ,QTc of groups P2 [(437.4 ± 24.4)ms vs. (453.3±28.0)ms]and P4 [(438.8±29.9)ms vs.(469.9±34.0)ms]were shortened significantly at T2 (P <0.05).Conclusion Propofol could improve ventricular reporlarization heterogeneity caused by cefu-roxime sodium.

Prolonged Tp-e Interval, Tp-e/QT Ratio and Tp-e/QTc Ratio in Patients with Type 2 Diabetes Mellitus

BACKGROUND: Type 2 diabetes mellitus (T2DM) is associated with increased risk of malignant ventricular arrhythmias. Cardiac electrical inhomogeneity may be the leading cause of the increased arrhythmic risk in patients with T2DM. The peak and the end of the T wave (Tp-e) interval and associated Tp-e/QT ratio are promising measures of ventricular repolarization indicating transmural dispersion of repolarization. The aim of this study was to assess ventricular repolarization in patients with T2DM by using Tp-e interval, Tp-e/QT ratio and Tp-e/corrected QT interval (QTc) ratio. METHODS: Forty-three patients with T2DM and 43 healthy control subjects, matched by gender and age, were studied. All participants underwent electrocardiography (ECG) recording. PR, RR and QT intervals represents the ECG intervals. These are not abbreviations. In all literature these ECG intervals are written like in this text. Tp-e intervals were measured from 12-lead ECG. Rate QTc was calculated by using the Bazett's formula. Tp-e/QT ratio and Tp-e/QTc ratio were also calculated. RESULTS: Mean Tp-e interval was significantly prolonged in patients with T2DM compared to controls (79.4±10.3, 66.4±8.1 ms, respectively; P<0.001). We also found significantly higher values of Tp-e/QT ratio and Tp-e/QTc ratio in patients with diabetes than controls (0.21±0.03, 0.17±0.02 and 0.19±0.02, 0.16±0.02, respectively; P<0.001). There was no difference in terms of the other ECG parameters between the groups. CONCLUSION: Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio were prolonged in patients with T2DM. We concluded that T2DM leads to augmentation of transmural dispersion of repolarization suggesting increased risk for ventricular arrhythmogenesis.

Effect of oxytocin on Tp-e and QTc interval during caesarean section / 中国医师进修杂志

Objective To evaluate the effect of oxytocin on Tp-e and QTc interval during caesarean section under spinal anesthesia in healthy puerperas. Methods Forty ASA Ⅰ puerperas were selected and allocated to receive oxytocin intravenous bolus group (group-IB) or oxytocin continuous infusion group (group-CI) with 20 puerperas in each by random digits table. An intravenous bolus of 5% glucose 5 ml and 5 U oxytocin was administered after delivery a 55-60 s period. A continuous infusion of 5% glucose 5 ml and 5U oxytocin was administered after delivery a 10 min period. Measured the QTc interval,Tp-e interval,mean arterial pressure (MAP) and beart rate ( HR ) pre-operatively, then 1,3 and 5 ain after spinal anesthesia, and at least 1,3,5 and 10 min after oxytocin injection. Results In group-IB:HR was fast 1 min after oxytocin injection compared with pre-operatively [(89 ± 13) beats/min vs. (73 ± 12) beats/min] ,MAP was decreased [(69 ± 12 ) mm Hg ( 1 mm Hg= 0. 133 kPa ) vs. ( 82 ± 13 ) mm Hg] and QTc interval was prolonged [(426 ±21 ) ms vs. (405 ± 18 ) ms] (P ＜ 0.01 ); but Tp-e interval was prolonged 1,3,5 min after oxytocin injection compared with pre-operatively (P ＜ 0.01 or ＜ 0.05 ). Conclusions Single large dose of oxytocin intravenous bolus (5 U) can prolong QTc interval and Tp-e interval in healthy puerperas, and Tp-e interval can exact predict the occurrence of ventricular arrhythmias. The risk-benefit balance of oxytocin bolus during caesarean delivery should be discussed with women with a history of long QT syndrome.

Tp-e/QT ratio as a predictive index of sudden cardiac death in patients with ST-segment elevation myocardial infarction / 西安交通大学学报(医学版)

Objective To detect Tp-e/QT ratio in patients with acute ST-segment elevation myocardial infarction (STEMI) and explore its clinical significance. Methods Healthy individuals and patients with acute STEMI were recruited in this study. Their first QTc,QTd and Tp-e were measured within 24 h after admission to hospital,and Tp-e/QT ratio was calculated so as to analyze the relation between Tp-Te/QT ratio and malignant ventricular arrhythmia. Results Compared with those of the healthy individuals,the intervals of QTd,Tp-e and QTc were significantly lengthened \[(33.66?16.76)ms vs. (55.29?31.12)ms,(89.55?12.61)ms vs. (142.65?39.33)ms,and (426.57?65.03)ms vs. (482.26?48.03)ms,P