TpTe Interval Research Articles

Immediate changes in depolarization and repolarization after left bundle branch area pacing and atrioventricular nodal ablation

BackgroundMalignant arrhythmia due to ventricular depolarization and repolarization alterations after atrioventricular node (AVN) ablation is a known clinical entity. Here, we aimed to demonstrate the ventricular depolarization and repolarization changes in patients who underwent left bundle branch area pacing (LBBaP) and AVN ablation. MethodsThis is a single-center, retrospective preliminary study (n = 10). All patients underwent single-chamber pacemaker implantation with LBBaP before the AVN ablation procedure. Electrocardiographic (ECG) parameters [QRS duration (QRSd), QTc (Fridericia formula), Tp-e, and JT interval] were measured and analyzed before and after the procedure. ResultsThe mean age of the study population was 67.1 ± 8.88 years, and 70 % of the patients were female. 60 % of the patients had AF, and 40 % of them had atrial tachycardia during the procedures. Eight patients had undergone more than two catheter ablations before the procedure. The QT interval (263.47 ± 26.79 vs. 416.14 ± 36.31 msec) and QRSd (93.3 ± 7.3 vs. 122.32 ± 21.16 msec) were prolonged when the patient's ECG parameters were analyzed. Still, the Tp-Te interval (75.57 ± 18.62 vs. 80.93 ± 17.35 msec) did not change, and the QTc (Fridericia formula) interval (425 ± 29.82 vs. 461.70 ± 35.33 msec) did not show a significant difference. ConclusionMalignant arrhythmia may occur due to ventricular depolarization and repolarization changes after the AVN ablation procedure. This study showed no significant change in Tp-e and QTc durations previously defined for malignant arrhythmia development. At the same time, JT time, which indicates ventricular repolarization duration, did not show a significant difference. LBBaP is more physiological and safer for patients planning to undergo AVN ablation.

Abstract 4115652: Effect of the sodium-glucose co-transporter 2 inhibitor, Dapagliflozin, on ventricular repolarization electrocardiographic parameters: DAPA-ECG study

Background: In patients with type 2 diabetes (T2D), hyperglycemia and glycemic variability lead to prolongation and greater heterogeneity of ventricular repolarization, manifested on the electrocardiogram through an increase in QT, QTc, TpeakTend (TpTe) intervals and the TpTe/QT ratio, increasing the risk of potentially malignant arrhythmias. Dapagliflozin has demonstrated efficacy in reducing cardiovascular events in T2D patients and in the risk of serious ventricular arrhythmias and sudden cardiac death. However, the exact mechanisms by which dapagliflozin confers this protection have not yet been fully elucidated. Goals/Aims: The main objective of the study was to evaluate the impact of dapagliflozin on the TpTe interval of patients with T2D, and secondarily, it examined its impact on various electrocardiographic parameters such as the QT and QTc intervals, the TpTf/QT ratio, QT dispersion, J-T peak interval, QRS-T angle and heart rate. Methods: This randomized, prospective, multicenter and open-label study involved 174 patients with T2D, divided into two groups: one treated with dapagliflozin and the other with optimized medical therapy without iSGLT2. Clinical, electrocardiographic, laboratory and echocardiographic evaluations were carried out at the beginning and after three months. The statistical analysis included means, standard deviations, quartiles, and frequencies, with 95% confidence intervals, using Chi-square (or Fisher) and t-test (or Mann-Whitney) for initial differences, and a linear mixed-effects model to evaluate the results, adopting a significance level of 0.05. Results: The TpTe interval was significantly reduced in the dapagliflozin group from 76.87 ± 12.47 to 67.80 ± 10.34 (p<0.001), and the QTc interval reduced from 424.07 ± 30.76 to 411.26 ± 25.31 (p=0.022). The TpTe/QT ratio in the dapagliflozin group was shortened from 0.20 ± 0.03 to 0.18 ± 0.02 (p<0.001). Both groups showed reductions in mean blood glucose and HbA1c, with a greater decrease observed in the control group. No significant changes were recorded in other variables analyzed. Conclusion: In patients with T2D, dapagliflozin significantly reduced the duration of the TpTe and QTc intervals, in addition to the TpTe/QT ratio. These findings indicate a decrease in ventricular electrical remodeling with a potential cardioprotective effect of dapagliflozin, which would partly explain its benefits in reducing potentially malignant ventricular arrhythmias and sudden cardiac death.

ECG Risk Score Model to Predict SCD in HFrEF: Retrospective Review in a Tertiary Centre

INTRODUCTION: Heart failure with reduced ejection fraction (HFrEF) patients need to be risk stratify as guidelines have shown that patients with left ventricularejection fraction (LVEF) <35% could be prevented from sudden cardiac death (SCD) by insertion of prophylactic implantable cardioverter-defibrillator (ICD). Thus we conducted a retrospective single tertiary centre study to evaluate the used of electrocardiogram (ECG) risk score model in identifying the individuals who at higher risk of SCD. MATERIALS AND METHODS: A total of 356 heart failure with reduced ejection fraction (HFrEF) patients treated at University Malaya Medical Centre between January 2017 and December 2021 were enrolled into this study. The patients’ demographics, types of heart failure, medications, and ECG parameters data were collected. The study outcomes were survivor or death in and the cause of death were subdivided into SCD or non-sudden cardiac death (non-SCD). RESULTS: A total of 156 study patients were survivor whereas another 120 had SCD and 70 had non-SCD. There were six ECG parameters that remained significant in the final model, namely the bundle branch block (BBB), abnormal P waves, QRS duration, QTc duration, TpTe interval and PR interval. The significant ECG parameters were combined into a risk score to enumerate prediction ability towards SCD. From our ECG risk score model, subject with ≥2 ECG abnormalities had more than 3-fold increased risk for SCD (HR 3.739, 95% CI 1.703-8.211, P 0.001) and the risk proportionately increased with increasing ECG abnormalities. CONCLUSION: Our findings suggested that the cumulative ECG risk score model was independently associated with SCD and particularly effective for LVEF <40% where risk stratification model remained scarce. So, we would like to propose for a prospective study to further evaluate our study outcome.

Tp-Te interval variation and its association with MACE as a metric of effective fibrinolysis in patients with STEMI from East India

Coronary artery disease (CAD) poses a significant health burden in India, and ST-elevation myocardial infarction (STEMI) is one of its most severe manifestations. The electrical activity is variable during STEMI, which produces dispersion and raises the T Peak-T End (Tp-Te) interval. STEMI is a medical emergency that requires prompt intervention to restore blood flow to the affected part of the heart muscle. Timely diagnosis and treatment are crucial in reducing morbidity and mortality associated with STEMI. Despite advancements in medical care, access to timely intervention and appropriate healthcare facilities remains a challenge in many parts of India, especially in rural areas. This single-center, prospective observational study included 150 STEMI patients. Clinical, demographic, and ECG data were recorded. The Tp-Te interval alterations and their relationship to major adverse cardiovascular events (MACE) in STEMI patients both during and after successful or unsuccessful fibrinolysis were examined. Patients without MACE had a significant mean decrease in the Tp-Te interval following successful fibrinolysis (i.e., 18.47 ± 5.66 ms vs. 10 ± 7.07 ms, p:0.039) compared to patients with MACE. It was found that after fibrinolysis, patients with a Tp-Te interval > 100 ms experienced much higher rates of death (4% vs. 0%, p:0.0001), arrhythmias (7.3% vs. 0.7%, p:0.0001), and heart failure (16% vs. 1.3%, p:0.0001), both while they were in the hospital and within 30 days of the index event. Our data shows that a decrease in the Tp-Te interval following fibrinolysis lowers the risk of MACE both during hospital stay and within 30 days following the index incident.

Association of transmural dispersion of ventricular repolarization (Tpeak-Tend interval) with components of metabolic syndrome: data from the ESSE-RF3

Aim. To study the associations of the Tpeak-Tend interval (TpTe) with components of metabolic syndrome (MS) in a sample of Novosibirsk residents.Material and methods. The study included 1042 residents of Novosibirsk (510 (48,9%) men) aged 35-74 years. The examination included the collection of demographic and social data, anthropometry, blood pressure (BP) measurement, and electrocardiography (ECG). MS was determined according to the 2013 criteria. The TpTe interval from the peak, as the maximum positive or negative T wave deviation, to the end of the T wave, was measured manually in lead V5. The corrected TpTe (cTpTe) interval was used in the study.Results. The cTpTe is inversely associated with female sex (B 3,390, 95% confidence interval (CI): (-5,516-2,504), p=0,001). The cTpTe interval is associated with a blood pressure (BP) ≥140/90 mm Hg (B 3,154, 95% CI: (1,614-4,688), p=0,001), low-density lipoprotein cholesterol (LDL-C) >3,0 mmol/l (B 1,818, 95% CI: (0,409-3,544), p=0,030), regardless of other MS components, sex and age. The cTpTe interval was higher in individuals with BP ≥140/90 mm Hg compared with individuals with BP <140/90 mm Hg (69,08 95% CI: 67,59-70,66 vs 65,93 95% CI: 64,60-67,24; p=0,001), and in persons with LDL-C >3,0 mmol/l (68,41 95% CI: 67,11-69,63 vs 66,60 95% CI: 65,02-68,23; p=0,023), compared with individuals with LDL-C <3,0 mmol/l.Conclusion. The cTpTe interval, considered as an indicator of transmural dispersion of ventricular repolarization, is shorter in women than in men and is associated with hypertension and atherogenic dyslipidemia, regardless of other MS components.

The assessment of adolescent obesity's effects on ventricular repolarization

BackgroundCurrently, there is a lack of research on the Tp-Te interval and Tp-e/QT ratio in obese adolescents who have metabolic syndrome. AimOur study aims to compare established ventricular repolarization parameters with these intervals and ratios in obese adolescents with or without metabolic syndrome, alongside a healthy control group, while exploring the association of these repolarization parameters with cardiovascular risk factors and echocardiographic variables. MethodsThe study included 100 obese adolescents and 50 lean subjects, with the obese participants categorized into two subgroups. The Tp-Te interval was identified as the duration from the peak to the end of the T wave. ResultsThe metabolic and non-metabolic syndrome obese groups exhibited significantly elevated QTc and TpTe values compared to the control group, with no statistically significant differences observed in minimum QT, maximum QT, QT dispersion, QTc dispersion, TpTe dispersion, and TpTe/QT ratio values among obese subjects with metabolic or non-metabolic syndrome and controls. Specifically, TpTe values were significantly elevated in the non-metabolic syndrome obese groups compared to controls, while minimum TpTe values were significantly elevated in the metabolic syndrome obese groups compared to controls, and the prolongation of the QTc interval was notably elevated in the obese groups than in controls. ConclusionsObese adolescents demonstrated an elevated TpTe interval compared to healthy controls, without any significant differences observed in TpTe dispersion, and TpTe/QT ratio values between the two groups. Results of our study showed that a negative correlation between TpTe and HDL-cholesterol and a positive correlation between the TpTe/QT ratio and insulin sensitivity indices in adolescents with metabolic syndrome.

Cerebral Ischemia and Reperfusion-Induced Changes in Left Ventricular Function and Electrocardiogram in Mice

Background: Stroke may produce functional and electrical heart disturbances. The underlying characteristics and mechanisms have not been fully elucidated. Objectives: To evaluate whether acute cerebral ischemia (I) and reperfusion (R) may cause cardiac dysfunction and electrocardiographic alterations in an experimental mice model. Methods: Male mice that underwent cerebral ischemia and reperfusion (I/R) were evaluated by electrocardiography (ECG) and echocardiography. Heart rate, corrected QT (QTc) interval, T-wave peak to T-wave end (Tp-Te) interval, left ventricular ejection fraction (LVEF), shortening fraction (SF) and isovolumetric relaxation time (IVRT) were analyzed. Cerebral infarct size was calculated, and neurological deficit was assessed with the Longa scale. Results: Twenty-four hours after R, a statistically significant decrease in LVEF (I/R: 66.5±1.5% vs. sham: 74.3±0.9%; p=0.002) and in SF (I/R: 42.9±1.7% vs sham: 52.3±1.7%; p=0.004) was observed. QTc interval prolongation was observed during I/R (baseline: 125.1±4.3 ms; 60 min after I: 143.8±5.2 ms; 24 h after R: 170.3±5.8 ms; p=0.002). Tp-Te interval was not prolonged during I (baseline: 25.9±1.3 ms vs. 60 min after I: 23.8±1.4 ms; p=0.999) but it was prolonged during R (24 h after R: 32.0±2.3 ms; p=0.049). Cerebral infarct size was 34.9±2.5% and survival in the I/R group was 43.3%. Conclusion: Acute cerebral ischemia induces mild left ventricular dysfunction and disturbances in ventricular repolarization which intensify within the first 24 hours after reperfusion.

Assessment of Tp-Te interval in patients with cardiac AL amyloidosis.

Prolonged Tp-Te interval is strongly associated with fatal ventricular arrhythmias and mortality. This association has been demonstrated in various diseases. However, the current literature does not give any information on Tp-Te interval in cardiac amyloid light-chain (AL) amyloidosis. We retrospectively screened 116 cardiac AL amyloidosis patients and 35 patients were included in the study. Demographic, laboratory, 12-lead electrocardiographic (QTc, Tp-Te V1-V6) and transthoracic echocardiographic data of the patients were analysed and compared with 35 healthy controls. QTc and Tp-Te V2-V5 were significantly prolonged in the cardiac AL amyloidosis group (p < 0.05). Also, there was a positive and statistically significant correlation between the parameters of QTc and Tp-Te V3-V6, and also between the parameters of interventricular septum thickness at enddiastole and Tp-Te V2-V5. We present the first strong evidence of prolonged Tp-Te intervals in patients with cardiac AL amyloidosis. There may also be a relationship between prolonged Tp-Te interval and the development of arrhythmia in this patient group, as in some other groups. There is a need for prospective studies examining the relationship of prolonged Tp-Te interval with arrhythmias and its prognostic significance in cardiac AL amyloidosis.

The Effects of Methylphenidate on Ventricular Repolarization Parameters in Children with Attention-Deficit Hyperactivity Disorder.

Long-acting methylphenidate (MPH), a psychostimulant agent, is widely used in the treatment of attention-deficit hyperactivity disorder (ADHD). Methylphenidate might cause an increment in the risk of lethal arrhythmias by deteriorating ventricular repolarization. QT intervals, the corrected QT (QTc), QT dispersion, T-peak to T-end (TpTe), and the TpTe/QTc ratio are the most utilized indicators of ventricular repolarization in electrocardiogram (ECG). The present study was conducted to examine the effects of long-term MPH use on the ECG in pediatric patients. A total of 52 children with ADHD and 51 age- and gender-matched controls were enrolled in the study. The children had been using MPH regularly for at least 6 months. Comparisons were made regarding ECG parameters, including the mean intervals of QT, QTc, QTc dispersion interval duration, TpTe intervals, TpTe/QT, and TpTe/QTc ratio. The median duration of treatment with MPH was 30 months (minimum-maximum: 6-120), and the median MPH dose was 30 mg/day (minimum-maximum: 18-54). The main findings showed significantly prolonged P-wave dispersion, TpTe interval, TpTe dispersion, and TpTe/QT and TpTe/QTc ratios in the ADHD group compared to the healthy controls (P < .001). These parameters were not associated with MPH dose or treatment duration. Additionally, nearly half of the patients had QTc values of 460 ms or higher, but there were no significant differences in treatment duration and dose compared to the remaining group (P = .792 and P = .126). Methylphenidate may have proarrhythmogenic effects in children with ADHD, which may not be adversely affected by long-term use and treatment dose. Considering the extensive use of MPH, cardiac monitoring of these children is important.

Abstract P2136: TpTe Interval Behavior And Mortality In Wistar Rats Submitted To Cardiac Ischemia And Reperfusion Treated With The Heparin Fragment Trisulfated Disaccharide

Introduction: The Tp-Te ekg interval reflects ventricular transmural dispersion, being used for prediction of ventricular arrhythmia and sudden death. The heparin fragment called Trisulfated Disaccharide (TD), which has no effect on blood coagulation and acts on the sodium-calcium exchanger accelerating the output of calcium from the cell, decreases cytoplasmic calcium concentrations in situations of calcium overload due to ischemia and reperfusion (I-R). Objective: To evaluate the behavior of the Tp-Te interval and mortality due to cardiac arest in Wistar rats submitted to surgicaly induced I-R under treatment with TD at reperfusion. Materials and Method: Wistar rats (n=8) with average weight of 300g were anesthetized and under assisted breathing were electrocardiographically monitored and submitted to surgical cardiac ischemia by ligation of the anterior descending artery for 10 min, with reperfusion thereafter. The Tp-Te interval was analyzed before ischemia, at 10 min after ischemia induction and at 10 min after reperfusion, The incidence of arrhythmias was determined throughout the recording period. In the study group intravenous (0.2 mg/kg) TD was injected concomitantly with the reperfusion. In the control group (n=8), the same procedure was performed, without the TD infusion. Results: During ischemia there was a similar alteration of the Tp-Te interval in both groups when compared to the pre-ischemic phase, with an increase of about 90% in magnitude, as well as the presence of ventricular arrhythmias, without animal mortality. During reperfusion Tp-Te interval returned to normal in the treated group and there was no mortality. In the control group, the magnitude of the Tp-Te increase was maintained. The presence of ventricular arrhythmias was similar, but total atrioventricular block and/or sustained arrhythmia occurred in 50% of the animals, followed by animals death. Conclusion: Treatment with TD at the time of reperfusion normalized the Tp-Te interval 10 min after TD infusion as well as reduced mortality in wistar rats submitted to I-R, and may be useful in the protection of organs submitted to the same I-R conditions (transplants, surgical and hemodynamic procedures), where calcium overload is determinant in morbidity and mortality.

Comparison of electrocardiographic parameters between left bundle optimized cardiac resynchronization therapy (LOT-CRT) and left bundle branch pacing-cardiac resynchronization therapy (LBBP-CRT).

In patients undergoing cardiac resynchronization therapy using left bundle branch area pacing (LBBP-CRT), the addition of a coronary sinus lead, that is, Left bundle optimized CRT (LOT-CRT) might confer additional benefits. To compare the electrocardiographic characteristics between LBBP-CRT and LOT-CRT MATERIALS AND METHODS: Patients with non-ischemic cardiomyopathy (NICMP) and left bundle branch block (LBBB) with left ventricular ejection fraction<35% who underwent implantation of an atrial lead, a left bundle lead, and a coronary sinus lead were included in this prospective study. Digital 12-lead electrocardiograms were recorded in three pacing modes-AAI, DDD with pacing from the LBB lead (LBBP-CRT), and DDD with pacing from both left bundle and coronary sinus leads (LOT-CRT). QRS duration (QRSd), QRS area, QT interval, and T peak-T end (TpTe) intervals were compared. Among 24 patients, QRSd reduced from 167±21.2ms to 134.5±23.6ms with LBBP-CRT (p<.001) and 129.5±18.6ms with LOT-CRT (p<.001) without a significant difference between LBBP-CRT and LOT-CRT (p=.15). Patients with QRS duration with LBBP-CRT>131ms showed a significant reduction in QRSd with LOT-CRT (p=.03). QT interval was reduced with both modes of CRT. LOT-CRT was associated with a greater reduction in QRS area (p=.001), TpTe interval (p=.03), and TpTe/QT ratio (p=.013) compared to LBBP-CRT. In patients with NICMP and LBBB, there was no significant difference in QRSd with LOT-CRT compared to LBBP-CRT. However, in patients with QRSd>131ms after LBBP-CRT, LOT-CRT resulted in a significantly narrower QRS.

Impact of coronary artery bypass grafting on ventricular repolarization indexes

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Ventricular repolarization indexes (VRI) tend to be altered in patients with chronic coronary artery disease, which are associated with a higher risk of malignant arrhythmias and higher mortality. Coronary artery bypass grafting (CABG) is capable of reducing mortality, as well as improving arrhythmic burden in this population. However, we do not know whether these benefits can be explained by improvement in VRI. Purpose To determine whether there is improvement in VRI after CABG, as well as to analyse possible effects of clinical and surgical variables on these indexes. Methodology A total of 150 patients who underwent CABG were included. Through the evaluation of preoperative and hospital discharge electrocardiograms, the QT interval, the interval from the peak to the end of T wave (Tp-Te) and the Tp-Te/ QT ratio were analysed. The values obtained before and after CABG were compared, as well as their association with clinical and surgical variables. Results The population was predominantly male (77.3 %), mean age of 61.6±8.3 years-old and mean LVEF of 58.8±10.6 %. A reduction in the QT interval (398.93±34.68 vs 365.47±50.38 ms, p &amp;lt; 0.001), in the Tp-Te interval (72.2±17.2 vs 61.6±19.5 ms, p &amp;lt; 0.001) and in the Tp-Te/ QT ratio (0.18±0.17 vs 0.04±0.05, p = 0.004) after CABG. There was no correlation between VRI and clinical and surgical variables. Conclusion CABG had a important impact in the reduction of QT and Tp-Te intervals, as well as the Tp-Te/ QT ratio, suggesting that the acute improvement in the coronary perfusion is directly associated with the improvement in these VRI.

Altered cardiac repolarization associated with cellular electrophysiological remodeling following chronic testosterone undecanoate administration in a canine model

Abstract Funding Acknowledgements Type of funding sources: None. Background The influence of testosterone on ventricular ion channels is widely investigated. Despite the legally stipulated availability of different androgen anabolic steroids (AAS), these agents are very popular among young adults, however, the direct effects of supra-physiological testosterone level are still unclear. Supposedly, the chronic use of AASs may result in structural and functional remodeling of the heart. Purpose The aim of our study was to investigate the potential electrophysiological effects of chronic administration of testosterone-undecanoate in a canine model in in vivo and in vitro studies. Methods Eight male beagle dogs were randomized into control (’Cont’) and treated (’Tr’) groups (n = 4; n = 4). The latter group received 15 mg/kg of long-lasting testosterone-undecanoate intramuscular injections weekly for 3 months. Blood samples were taken for monitoring testosterone levels. To investigate the altered repolarization in conscious dogs electrocardiography studies were performed. Ventricular myocytes were enzymatically dissociated via retrograde perfusion. The transmembrane ionic currents were recorded using the whole-cell configuration of the patch-clamp technique and the action potential duration (APD) was measured by the perforated patch-clamp technique. Results Testosterone level was significantly higher in the ‘Tr’ group compared to the ‘Cont’ group (47.02 nm/L vs. 15.23 nm/L; p=0.0002). The chronic treatment did not affect the heart rate between the examined groups (93.7±23.5 vs.108.8±21.4 beats/min), however, it resulted in significantly shortened QT (226±49 vs. 244.9±26.6 ms; p&amp;lt;0.05) and QTc (26.06±2.5 vs. 29.6±3.01 ms, p&amp;lt;0.05) intervals. ECG recordings also presented prolonged PQ (112.1±15.5 vs. 61.65±12.7ms; p&amp;lt;0.05), QRS (72.37±15.4 vs. 61.65±12.7 ms; p&amp;lt;0.05), and Tp-Te (32.95±7.45 vs. 53.46±16.6 ms; p&amp;lt;0.05) intervals in the ‘Tr’ group. Additionally, the APD of isolated left ventricular myocytes significantly shortened in the ‘Tr’ group compared to the ‘Con’ group (235.2±26.7 vs. 283.6±28.5 ms; p&amp;lt;0.05). Patch-clamp experiments revealed increased magnitude of transient outward potassium current (Ito), the inward rectifier potassium current (Ik1), and the slowed delayed rectifier potassium current (Iks) in the ‘Tr’ group. Conclusion The repolarization of the canine ventricular myocardium was significantly modified by constantly high level of testosterone. Many beneficial effects are attributed to physiological testosterone levels; however, the supra-physiological testosterone level may lead to potentially harmful alternations in the cardiac repolarization that may promote arrhythmogenesis, especially in the presence of various heart diseases. Presumably, the constantly high testosterone level induced electrophysiological changes may contribute to the development of life-threatening arrhythmias under certain circumstances.

Prognostic Value of T peak-T end Interval on Surface ECG in Patients Undergoing Reperfusion Therapy for ST Segment Myocardial Infarction

Background: In post-ST-segment elevation myocardial infarction (STEMI) patients, the indices of repolarization on electrocardiogram (ECG) have shown promise for the prediction of death and malignant arrhythmias. In our study, we analyzed prospectively, in patients with STEMI undergoing reperfusion therapy, the acute effects of the reperfusion on the Tpeak-Tend (TpTe) and its predictive value for 30-day mortality, ventricular arrhythmias, and heart failure. Materials and Methods: We studied 75 STEMI patients aged 18–80 years admitted to Nizam’s Institute of Medical Sciences, Hyderabad, over 6 months. ECGs were taken before and 90 min after reperfusion. TpTe interval was measured before (pre-TpTe) and after reperfusion (post-TpTe). 24-h Holter monitoring was recorded within 72 h of reperfusion to look for any arrhythmias. Patients were followed up for a period of 30 days, and all the major adverse cardiac events (MACE) if any, were noted. Results: In the primary percutaneous transluminal coronary angioplasty (PTCA) group, the mean change in TpTe after intervention was 19.7 ± 16.7 ms, whereas in thrombolysis group, it was 10.7 ± 13.8; and the difference was statistically significant (P &lt; 0.05), suggesting the superiority of primary PTCA compared to thrombolysis. When pre-TpTe interval was compared between who survived (69) and who succumbed (09), higher values were seen in patients who succumbed to death (115 ± 5.48) versus (88 ± 16.5) (P &lt; 0.05). Pre-TpTe value of 105 had 100% sensitivity and 83% specificity in predicting mortality. Conclusion: Primary PTCA was superior to thrombolysis in reducing the TpTe interval and MACE events. The pre-TpTe interval could predict 30-day mortality and ventricular arrhythmias in the immediate and late period after revascularization in STEMI.

The predictive value of Tp-Te interval, Tp-Te/QT ratio, and QRS-T angle of idiopathic ventricular tachycardia in patients with ventricular premature beats.

Identify idiopathic ventricular tachycardia in patients with ventricular premature beats was required to have effectively treatment. The aim of this study is to investigate the predictive value of Tp-Te interval, Tp-Te/QT ratio, and QRS-T angle of idiopathic ventricular tachycardia in patients with idiopathic ventricular premature beats. One hundred and seventy-eightpatients who had undergone premature ventricular complex/ventricular tachycardia (PVC/VT) ablation between January 1,2020 and August 30, 2022 constituted our study population as ventricular arrhythmia group. Seventy-fivehealthy people were selected as control group. Patients with no episode of VT were classified as PVC group, while with any episode of VT that has the same morphology with PVC were classified as PVC with VT group. Patients in PVC with VT group were divided into two groups: nonsustained VT group (duration of any episode of VT below 30 s) and sustained VT group (duration of any episode of VT over 30 s). Tp-Te interval, Tp-Te/QT ratio and QRS-T angle were compared in groups. Tp-Te interval, Tp-Te/QT ratio and patients with increased QRS-T angle in PVC with VT group were higher or more than those in PVC group (p < .001). The value of combined diagnosis of these indexes was higher. Tp-Te interval was longer in the sustained VT group compared to the nonsustained VT group (p = .009). Tp-Te interval, Tp-Te/QT ratio, and QRS-T angle may have a predictive value of presence of idiopathic VTin patients with premature beats and the combined prediction of these indexes is more valuable. Tp-Te interval maybe helpful for prediction of sustained idiopathic VT.

The effect of coronary slow flow on ventricular repolarization parameters

IntroductionIschemia due to microvascular dysfunction may be responsible for the heterogeneity of ventricular repolarization in coronary slow flow. To our knowledge, there is no study in which QT interval, Tp-Te interval, index of cardiac-electrophysiological balance (iCEB), and frontal QRS-T angle were evaluated together in patients with CSF. In this study, we examined for the first time the relationship between all these myocardial repolarization parameters and CSF. Materials and methodsThe study group included 178 patients (99 female, mean age: 50.6 ± 8.6 years) with isolated CSF without stenotic lesions and with angiographically proven normal coronary arteries. The control group included 120 patients (71 female, mean age: 49.3 ± 9.4 years) with normal coronary angiography. QRS duration, QT interval, QTc interval, Tp-Te interval, Tp-Te/QT, Tp- Te/QTc, iCEB score, and frontal QRS-T angle were calculated from 12‑lead ECGs. ResultsThere was no significant difference in demographic parameters between the two groups. Compared with the control group, patients with CSF had significantly longer QTmax duration, QT dispersion, Tp-Te interval, and higher iCEB score, wider frontal QRS-T angle. ConclusionIn our study, we found that many of the ventricular repolarization parameters were adversely affected in patients with CSF. Impaired parameters may be associated with the risk of malignant ventricular arrhythmias.

Tp-Te Interval and Tp-Te/QT Ratio Predict Coronary Artery Disease Severity in Non-ST Segment Elevation Acute Myocardial Infarction

Tp-Te Interval and Tp-Te/QT Ratio Predict Coronary Artery Disease Severity in Non-ST Segment Elevation Acute Myocardial Infarction

The Effect of Antipsychotics and Their Combinations with Other Psychotropic Drugs on Electrocardiogram Intervals Other Than QTc among Jordanian Adult Outpatients.

The ECG changes produced by antipsychotics and other psychotropic medications are studied mostly regarding QTc interval prolongation. This study aimed to investigate ECG changes beyond long QTc interval produced by psychotropic medications. A cross-sectional study was conducted to assess the effect of these agents on RR, PR, TpTe intervals and TpTe/QT ratio among Jordanian outpatients. The RR interval was significantly shorter among patients on TCAs versus those not receiving TCAs and among patients on polytherapy versus those on monotherapy (p &lt; 0.05 for both comparisons), when adjusted for age, gender, BMI, caffeine intake, smoking, presence of diabetes mellitus, cardiovascular disease and medications known to produce heart rate changes. Positive correlations were found between the PR interval and age in patients treated with SGAs, SSRIs, citalopram, polytherapy and in the total sample (p &lt; 0.01 for all). Inverse correlations were found between the RR interval and the number of psychotropic medications among patients treated with SSRIs and in the whole study sample (p &lt; 0.01 for both). In conclusion, various ECG changes beyond QTc interval prolongation are observed in patients on antipsychotics and other psychotropic medications, in those on polytherapy. It is recommended to obtain an ECG before starting patients on psychotropic drugs known to produce electrocardiographic changes and their combinations.

T-Peak to T-End Interval for Prediction of Positive Response to Ajmaline Challenge Test in Suspected Brugada Syndrome Patients

Brugada syndrome (BrS) is diagnosed in patients with ST-segment elevation with coved-type morphology in the right precordial leads, occurring spontaneously or after provocative drugs. Due to electrocardiographic (ECG) inconsistency, provocative drugs, such as sodium-channel blockers, are useful for unmasking BrS. Ajmaline is superior to flecainide and procainamide to provoke BrS. Prolonged T-peak to T-end (TpTe) is associated with an increased risk of ventricular arrhythmia and sudden cardiac death in Brugada syndrome patients. This study aimed to investigate the predictive value of T-peak to T-end interval and corrected T-peak to T-end interval for predicting the positive response of the ajmaline challenge test in suspected Brugada syndrome patients. Patients who underwent the ajmaline test in our center were enrolled. Clinical characteristics and electrocardiographic parameters were analyzed, including TpTe, corrected TpTe, QT, corrected QT(QTc) interval, and S-wave duration, compared with the result of the ajmaline challenge test. The study found that TpTe and corrected TpTe interval in suspected BrS patients were not significantly associated with a positive response to the ajmaline challenge test. The T-peak to T-end interval and corrected T-peak to T-end interval could not predict the positive response of the ajmaline challenge test in suspected Brugada syndrome patients.

Association between ventricular premature contraction burden and ventricular repolarization duration.

Premature ventricular contraction is generally known as benign in the absence of structural heart disease; however, premature ventricular contraction-induced left ventricular systolic dysfunction or ventricular arrhythmias are defined in some cases. Ventricular repolarization duration differs between myocardial cells, which causes myocardial electrical heterogeneity and is thought to be responsible for ventricular arrhythmias. In our study, we aimed to evaluate the association of ventricular repolarization parameters including Tp-Te interval, Tp-Te/QT ratio, and QRS-T angle with premature ventricular contraction frequency in patients with premature ventricular contraction burden. A total of 80 subjects who were admitted to our cardiology department and underwent 24-h electrocardiography Holter monitoring were included. Patients were divided into two groups: group 1 is defined as premature ventricular contraction burden that had frequent premature ventricular contraction ≥1% in 24-h Holter monitoring, and group 2 is defined as rare premature ventricular contraction <1% in 24-h Holter monitoring. Tp-Te interval and Tp-Te/QT ratio are statistically significantly prolonged in the premature ventricular contraction burden group than in the control group (85.3±13.9 vs. 65.7±11.9, p<0.001; 0.19±0.03 vs. 0.15±0.02, p<0.001, respectively). QRS-T angle was statistically significantly abnormal in the premature ventricular contraction burden group (p=0.024). Increased Tp-Te interval and widened QRS-T angle are associated with ventricular arrhythmias and might be used for the prediction of premature ventricular contraction burden in patients with premature ventricular contraction in electrocardiography in the absence of 24-h Holter monitoring.