Ventricular Repolarization Parameters Research Articles

Evaluation of Symptomatic and Asymptomatic Outpatients in the Post-COVID-19 Period With Electrocardiographic Ventricular Depolarization and Repolarization Parameters

Evaluation of Symptomatic and Asymptomatic Outpatients in the Post-COVID-19 Period With Electrocardiographic Ventricular Depolarization and Repolarization Parameters

Evaluation of Tp-e interval, Tp-e/QT, and Tp-e/QTc ratio in primary hyperparathyroidism before and after parathyroidectomy

Aims: This study aimed to evaluate Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratios, which are new ventricular repolarization (VR) parameters in primary hyperparathyroidism (PHPT) patients, and also investigate the potential effect of parathyroidectomy (PTx) on these parameters. Methods: In total, 27 patients with PHPT who underwent PTx and 25 control subjects were selected for our study. Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratios of patients planned for PTx were compared to healthy matched controls. Electrocardiographic parameters measured 6 months after the surgery were also compared with preoperative values for each patient. Results: Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio were significantly higher in PHPT patients compared to the control group (p<0.001, for all).It was observed that the parameters mentioned after surgery decreased significantly, and there was no statistical difference when compared to the control group.The correlation analysis revealed a significant and positive correlation between corrected calcium (CCa) and PTH levels with Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio (for Ca; r=0.515, p=0.006; r=0.398, p=0.040; r=0.797, p<0.001 respectively vs. for PTH; r=538, p=0.04; r=0.422, p=0.028; r=0.812, p<0.001 respectively). Conclusions: This study showed that Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios were prolonged in PHPT.These values, which are accepted as an indicator of sudden cardiac death after PTx, decreased significantly. In addition, both high PTH and high calcium(Ca) levels appear to have the potential to cause arrhythmogenic effects separately.

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.

Evaluation of the effects of insulin resistance on ECG parameters in obese children.

Obese people are at increased risk of arrhythmia and sudden death, even in the absence of heart dysfunction. Increased insulin resistance, neurohumoral and autonomic changes in obesity can cause atrial and ventricular repolarization abnormalities. This study aimed to investigate the effect on ventricular repolarization parameters and to show the increased risk of ventricular arrhythmia in obese children. The data of 50 obese children aged 2-18 who applied to the Pediatric Endocrinology Outpatient Clinic were evaluated prospectively. In 12-lead ECGs, heart rate, Pmax, Pmin, P-wave dispersion (Pwdisp), QTmax, QTmin, QT dispersion (QTd), QTcmax, QTcmin, QTc interval dispersion (QTcd), Tpeak-Tend interval (Tp-e), Tp-e/QT, Tp-e/QTc were calculated electronically. Tp-e time (0.041 ± 0.004/0.049 ± 0.015/p=0.018) and Tp parameters were measured in obese children with and without insulin resistance. Tp-e/QT ratio was also found to be high (p=0.035). There is a negative correlation between BMI SDS values and QTcmax and QTcmin values in patients with insulin resistance (p=0.015). In our study, the Tp-e interval and Tp-e/QT ratios, which had been revealed in literature to be more sensitive in demonstrating ventricular arrhythmias, were found to be higher in obese individuals with insulin resistance than in those without insulin resistance. Obese individuals with or without insulin resistance should be carefully evaluated in terms of atrial and ventricular depolarization and repolarization parameters with 12-lead ECG during their outpatient controls, and annual 24-hour Holter control should be performed to detect arrhythmias.

The Impact of Transcatheter Atrial Septal Defect Closure on Ventricular Repolarization Parameters in Children: Results from a 15-Year Single-Center Tertiary Care Experience

The Impact of Transcatheter Atrial Septal Defect Closure on Ventricular Repolarization Parameters in Children: Results from a 15-Year Single-Center Tertiary Care Experience

Ranolazine improved left ventricular diastolic functions and ventricular repolarization indexes in patients with coronary slow flow.

Coronary slow flow (CSF) is a condition commonly encountered during angiography. Recent studies have shown the adverse effects of CSF on left ventricular diastolic functions. CSF reportedly increases the novel ventricular repolarization parameters. Ranolazine is a preparation with a prominent anti-anginal activity that has positive effects on anti-arrhythmic and diastolic parameters. In this context, this study was carried out to investigate the effects of ranolazine on left ventricular diastolic functions and repolarization in patients with CSF. Forty-six patients with CSF and 29 control subjects were included in the patient and control groups, respectively. Both groups received ranolazine for one month and were evaluated using 12-lead electrocardiography, conventional echocardiography, and tissue Doppler imaging at the baseline and after one month of ranolazine treatment. Corrected P, QT dispersion, and Tp-e interval values were significantly higher in the patient group than in the control group. There was a significant decrease in isovolumic relaxation time (IVRT) and deceleration time (DT) values after the ranolazine treatment compared to the baseline values in the patient group but not the control group. A significant increase was observed in the mean E and A velocities and the mean E/A ratio after the ranolazine treatment compared to the baseline values in the patient group. Additionally, there was a significant difference between the Tp-e interval and corrected P dispersion values measured after the ranolazine treatment compared to the baseline values in the patient group but not in the control group. This study's findings demonstrated that ranolazine positively affected impaired diastolic functions and repolarization parameters, particularly in patients with CSF.

Index of cardiac-electrophysiological balance in relapsing-remitting multiple sclerosis patients treated with fingolimod.

Fingolimod is indicated for the treatment of relapsing-remitting multiple sclerosis (RRMS) and also targets cardiovascular system due to receptors on cardiomyocytes. Results of previous studies are controversial for the effect of fingolimod in terms of ventricular arrhythmias. Index of cardio-electrophysiological balance (iCEB) is a risk marker for predicting malignant ventricular arrhythmia. There is no evidence on the effect of fingolimod on iCEB in patients with relapsing-remitting multiple sclerosis (RRMS). The aim of this study was to evaluate iCEB in patients with RRMS treated with fingolimod . A total of 86 patients with RRMS treated with fingolimod were included in the study. All patients underwent a standard 12-lead surface electrocardiogram at initiation of treatment and 6h after treatment. Heart rate, RR interval, QRS duration, QT, QTc (heart rate corrected QT), T wave peak-to-end (Tp-e) interval, Tp-e/QT, Tp-e/QTc, iCEB (QT/QRS) and iCEBc (QTc/QRS) ratios were calculated from the electrocardiogram. QT correction for heart rate was performed using both the Bazett and Fridericia formulas. Pre-treatment and post-treatment values were compared. Heart rate was significantly lower after fingolimod treatment (p< 0.001). While the post-treatment values of RR and QT intervals were significantly longer (p< 0.001) and post-treatment iCEB was higher (median [Q1-Q3], 4.23 [3.95-4.50] vs 4.53 [4.18-5.14]; p< 0.001), it was found that there was no statistically significant change in iCEB and other study parameters derived using QT after correcting for heart rate using both of two formulas. In this study, it was found that fingolimod did not statistically significantly change any of the heart rate-corrected ventricular repolarization parameters, including iCEBc, and it is safe in terms of ventricular arrhythmia.

Predicting Long-Term Ventricular Arrhythmia Risk in Children with Acute Lymphoblastic Leukemia Using Normal Values of Ventricular Repolarization Markers Established from Japanese Cohort Study.

Cardiac complications due to anthracycline treatment may become evident several years after chemotherapy and are recognized as a serious cause of morbidity and mortality in cancer patients or childhood cancer survivors. We analyzed ventricular repolarization parameters in electrocardiography for pediatric acute lymphoblastic leukemia patients during chemotherapy and in long-term follow-up. To establish the reference values of ventricular repolarization parameters in children, we retrospectively summarized the Tpe interval, QT interval, QTc interval, and Tpe/QT ratio in healthy Japanese children. Electrocardiography data recorded from students in 1st and 7th grades were randomly selected from a database maintained by the school-based screening system in the Oita city cohort, Japan. Subsequently, chronological data of the Tpe/QT ratio in 17 pediatric patients with acute lymphoblastic leukemia were analyzed over time. The mean ± standard deviation of the Tpe interval in 1st and 7th graders was 70 ± 7 and 78 ± 17 ms, respectively, while the mean ± standard deviation of the Tpe/QT ratio was 0.21 ± 0.02 and 0.22 ± 0.02 ms, respectively. During the intensive phase of treatment, the Tpe/QT ratios of 3 high-risk patients among the 17 patients with acute lymphoblastic leukemia exceeded the upper limit. The Tpe/QT ratio has a potential clinical application in predicting the risk of long-term ventricular arrhythmia of cancer patients or childhood cancer survivors from childhood to adulthood.

Evaluation of the changes in electrocardiographic ventricular repolarization parameters after COVID-19 recovery in hemodialysis patients.

Coronavirus disease-2019 (COVID-19) has cardiac manifestations. Data about electrocardiogram (ECG) changes after COVID-19 recovery is limited in hemodialysis patients. We aimed to investigate the changes in ventricular repolarization parameters after COVID-19 recovery in hemodialysis patients. Fifty-five hemodialysis patients who recovered from COVID-19 infection were included. QT interval, Tp-e interval, corrected QT (QTc), QTc dispersion, and Tp-e dispersion values were determined on the patients' ECGs, taken before COVID-19 and at least 1 month after recovery. The patients' data before COVID-19 infection and after recovery were compared. It was found that longest QTc (QTcmax) and QTc dispersion values after recovery were prolonged compared with pre-infection period (427 ± 28 ms vs. 455 ± 26 ms, p = 0.000 and 39 ± 16 ms vs. 65 ± 20 ms, p = 0.000). In our hemodialysis patients, ventricular repolarization parameters increased after COVİD-19 recovery. In hemodialysis patients, already predisposed to arrhythmic deaths, arrhythmia risk after COVİD-19 recovery may become more pronounced.

Temporal change in repolarization parameters after surgical correction of valvular heart diseases.

Ventricular tachyarrhythmia is a potentially fatal outcome of cardiac surgery. Abrupt changes in the hemodynamics after surgical correction of valvular heart disease (VHD) can lead to alterations in ventricular repolarization. We compared the difference between temporal changes in repolarization parameters after correction of left-sided VHD. We retrospectively analyzed the electrograms of patients who underwent surgical correction of isolated VHD between 2006 and 2015 at Asan Medical Center, including mitral stenosis (MS), mitral regurgitation (MR), aortic stenosis (AS), and aortic regurgitation (AR). Ventricular repolarization parameters were measured at pre-specified time intervals after index surgery using a custom-made ECG analysis program. We compared repolarization parameters, including QT and corrected QT intervals, T peak-to-end interval, and corrected T peak-to-end interval. Analysis of 8265 ECGs from 2110 patients (266 MS, 1059 MR, 421 AS, and 364 AR) was performed. Patients with AS were characterized by older age and more comorbidities than other VHDs. The corrected QT interval showed a peak value immediately after surgery and decreased thereafter in the AS groups. However, a gradual increase over 1month after surgery in AR, MS, and MR groups was observed. The corrected T peak-to-end interval increased in the MS and MR groups and was unchanged in the AS and AR groups. The repolarization parameters of surgery changed dynamically after left-sided valvular surgery. Understanding differential temporal change of repolarization parameters according to the type of VHD would help clinicians avoid fatal arrhythmias related to the repolarization changes.

The effect of dapagliflozin therapy on ventricular repolarization parameters in electrocardiography in patients with diabetic cardiovascular disease

BackgroundDapagliflozin is an agent that has both antihyperglycemic effects and is significantly associated with a lower risk of cardiovascular events in patients with diabetes mellitus (DM). However, there is insufficient data and information about the effect of dapagliflozin on electrocardiographic (ECG) parameters. AimThe effects of dapagliflozin on ventricular repolarization parameters have not been fully elucidated yet. This study aimed to investigate whether dapagliflozin has a positive effect on ventricular repolarization heterogeneity parameters in patients with type 2 DM. MethodWe retrospectively enrolled 140 patients with a known diagnosis of type 2 DM who were newly prescribed dapagliflozin in addition to standard anti-diabetic therapy. The patients were divided into two groups according to whether they had cardiovascular disease (CVD). The effect of dapagliflozin treatment on ventricular repolarization parameters (frontal plane QRST angle, Tp-e interval, Tp-e/QTc, QTc, and QTc dispersion) was investigated, patient groups were compared before and after treatment. ResultsAmong 140 patients, 70 (50 %) had CVD and 70 (50 %) did not have CVD. Dapagliflozin treatment resulted in significant reductions in ventricular repolarization parameters over the study period in the CVD group with diabetes. Mean fQRST angle, Tp-e interval, Tp-e/QTc, QTc, and QTc dispersion were significantly lower than baseline values at 6-month follow-up visits in the CVD group (61.61 ± 9.22° vs 52.55 ± 8.31°, 74.45 ± 16.06 msec vs 63.27 ± 13.99 msec, 0.19 ± 0.03 vs 0.16 ± 0.03, 384.12 ± 47.93 msec vs 356.15 ± 43.31 mesc, 55.28 ± 5.50 msec vs 48.08 ± 6.48 msec for all pairwise comparisons p < 0.001). ConclusionSimilar antihyperglycemic effects were found with dapagliflozin treatment in patients with and without CVD. However, significant reductions in ventricular repolarization parameters were observed only in patients with CVD.

Effect of Smokeless Tobacco (Maras Powder) on the Epicardial Fat Thickness and Ventricular Repolarization Parameters.

Background and Objectives: Smokeless tobacco (ST) use has recently become an alternative to cigarettes, and it has been concluded that ST is at least as harmful as cigarettes. ST use is thought to play a role in the pathogenesis of arrhythmia by affecting ventricular repolarization. In this study, we aimed to examine the relationships of Maras powder (MP), one of the ST varieties, with epicardial fat thickness and new ventricular repolarization parameters, which have not previously been described. Materials and Methods: A total of 289 male individuals were included in this study between April 2022 and December 2022. Three groups, 97 MP users, 97 smokers, and 95 healthy (non-tobacco), were compared according to electrocardiographic and echocardiographic data. Electrocardiograms (ECG) were evaluated with a magnifying glass by two expert cardiologists at a speed of 50 m/s. Epicardial fat thickness (EFT) was measured by echocardiography in the parasternal short- and long-axis images. A model was created with variables that could affect epicardial fat thickness. Results: There were no differences between the groups regarding body mass index (p = 0.672) and age (p = 0.306). The low-density lipoprotein value was higher in the MP user group (p = 0.003). The QT interval was similar between groups. Tp-e (p = 0.022), cTp-e (p = 0.013), Tp-e/QT (p =0.005), and Tp-e/cQT (p = 0.012) were higher in the MP user group. While the Tp-e/QT ratio did not affect EFT, MP predicted the epicardial fat thickness (p < 0.001, B = 0.522, 95%CI 0.272-0.773). Conclusions: Maras powder may play a role in ventricular arrhythmia by affecting EFT and causing an increase in the Tp-e interval.

Evaluation of the relationship between speckle tracking echocardiography and arrhythmia markers Tp-e interval and Tp-e/QTc in patients with arterial hypertension.

The prolongation of the Tp-e interval, which is defined as the interval from the peak to the end of the T wave on electrocardiography (ECG), is considered a non-invasive predictor of malignant ventricular arrhythmia development. In our study, we aimed to compare the Tp-e interval and Tp-e/QTc ratios on ECG and subclinical myocardial dysfunction evaluated by left ventricular global longitudinal strain (LV-GLS) imaging in patients receiving treatment for hypertension.Two-dimensional speckle tracking echocardiography was performed in 102 consecutive hypertensive patients with blood pressure values regulated by treatment. The normal left ventricular global longitudinal strain (LV-GLS) limit was accepted as < -18%. The patients were divided into two groups: those with normal (≥ -18%) LV-GLS and those with impaired LV-GLS (< -18%). Comparisons between the groups were made by measuring ventricular repolarization parameters, such as QT, QTc, and Tp-e intervals, and Tp-e/QT and Tp-e/QTc ratios.While the mean age of the patients with impaired LV-GLS was 55±6 years, the mean age of the normal LV-GLS group was 58±9 years (p=0.101). The Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios were significantly higher in the impaired LV-GLS group than in the normal LV-GLS group (p<0.05 for all). A positive correlation was observed between the ventricular repolarization parameters and LV-GLS values. This positive correlation was statistically significant in terms of the Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios.The Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios were increased in hypertensive patients with impaired LV-GLS, and therefore a close follow-up in terms of increased arrhythmia risk is required in this patient group.

Patients with Achilles Tendon Rupture Are Prone to Develop Ventricular Arrhythmia.

This study aimed to examine the ventricular repolarization (VR) disturbances of patients operated on for acute spontaneous Achilles tendon ruptures (ATRs), by comparing them with a healthy individual control group. Between June 2014 and July 2020, a total of 29 patients (28 males, 1 female; mean age: 40 ± 9.78 years; range, 21-66 years) who presented to the emergency department within the first three weeks of injury, and were diagnosed with acute spontaneous ATRs and treated with an open Krackow suture technique, were retrospectively analyzed. Fifty-two healthy individuals (47 males, 5 females; mean age: 39 ± 11.45 years; range, 21-66 years) were recruited as a control group from the cardiology outpatient clinic. Clinical data (demographic features and laboratory parameters (serum glucose, creatinine, hemoglobin, white blood cell count, and lipid profile)) and electrocardiograms (ECGs) were collected from medical records. ECGs were evaluated for heart rate and VR parameters of QRS width, QTc interval, cQTd interval, Tp-e interval, and Tp-e/QT ratio. The clinical data and these ECG parameters were compared between groups. There was no statistically significant difference between groups, regarding clinical data (all p < 0.05). Among ECG parameters, heart rate, QRS width, QTc interval, and cQTd interval were similar between groups (all p < 0.05). There were two important statistically significant findings of this research: The mean Tp-e interval was longer (ATR group: 72.4 ± 24.7, control group: 58.8 ± 14.5, p: 0.01), and the Tp-e/QT ratio was higher (ATR group: 0.2 ± 0.1, control group: 0.16 ± 0.4, p: 0.027) in the ATR group. According to the ventricular repolarization disturbances found in this study, patients with ATR may be at a higher risk of ventricular arrhythmia than healthy people. As a result, ATR patients should be assessed for ventricular arrhythmia risk by an expert cardiologist.

Evaluation of novel ventricular repolarization parameters in patients with acromegaly

Objectives: T wave’s peak and end interval (Tp-e), Tp-e/QT ratio and Tp-e/QTc ratio are novel markers of ventricular repolarization and are associated with ventricular arrhythmias. Increased ventricular arrhythmia incidence is reported in patients with acromegaly. The purpose of this study is to evaluate ventricular repolarization using the Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio in patients with acromegaly. Methods: Thirty-five patients with acromegaly were included in the study. The control group was consisted of forty-one subjects without acromegaly that having similar age, sex ratio and comorbidities. The Tp-e interval, Tp-e/QT ratio, Tp-e/QTc ratio, and other ventricular repolarization parameters of all patients were evaluated using electrocardiography. Results: Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio were significantly prolonged in patients with acromegaly compared to the control group. Furthermore, Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio showed a significant correlation with plasma GH levels and LVMI values. Conclusions: Our study revealed that Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio are prolonged in patients with acromegaly. We believe that the Tp-e interval, Tp-e/QT ratio, and Tpe/QTc ratio can be used in the evaluation of increased cardiovascular risk in patients with acromegaly.

Çölyak Hastalarında Elektrokardiyografik Değerlendirmenin Önemi

At the present study, study we aimed to analyze the risk factors for cardiac arrhythmias related disease factors by evaluating some ventricular repolarization parameters in the electrocardiographic (ECG) evaluation of CD. The study was conducted retrospectively from the files of the patients. The ECG evaluation of 63 patients aged 5-18 years diagnosis with CD and 63 healthy control group in Adana City Training and Research Hospital, between 01.2018-11.2022. Patients who were taking any drugs, who had a chronic disease and/or abnormal tests (vitamin B12, folate, tissue transglutaminase, anti-endomysium antibody titers) were excluded from the study. The ventricular repolarization parameters (QT interval, QTc interval, QT dispersion, QTc dispersion, Tp-e interval, Tp-e/QT, Tp-e/QTc) analyzed on ECG and compared both groups. The measured ventricular repolarization parameters of the patients and control groups were not statistically different. From the ECG data, it was found that the QTc min value was higher in patients diagnosed before 5 years old than the patients diagnosed after 8 years old. While the QTc dispersion was higher in patients diagnosed after 8 years old than the patients with an age at diagnosed before 5 years old. It was found that the values of QT min, QT max, and QT in the ECG were influenced by the duration of the disease and significantly high related with the disease duration (more than 5 years). We found that QTc dispersion was higher in patients with a later diagnosis. This suggests that cardiac involvement is also increased in patients with a late diagnosis.

Hafif Akut Miyokarditli Genç Hastalarda İnteratriyal Blok ve Ventriküler Repolarizasyon Parametreleri

Objective: To evaluate ECG findings regarding interatrial block and ventricular repolarization and certain biochemical parameters in young patients diagnosed as acute myocarditis with normal ventricular functions. Materials and Methods: 405 patients under the age of 35 who underwent diagnostic coronary angiography between January 2014 and January 2020 were retrospectively analyzed. Patients whose ECG records could not be accessed or quality were not suitable for evaluation, with sudden cardiac death, cardiomyopathy, ejection fraction &amp;lt;50%, diabetes mellitus, hypertension, chronic kidney and liver failure were excluded. Patients who underwent diagnostic angiography for the differential diagnosis of acute myocarditis were assigned to myocarditis group (n: 35), and age– and sex–matched subjects with normal coronary circulation and underwent coronary angiography for any other reason were assigned to control group (n: 35). Results: Heart rate, P wave duration, P wave peak time, PR interval, QRS, QT, and Tp–e interval, QTc, Tp–e/QT and Tp–e/QTc ratios did not differ from each other. Whereas troponin (p&amp;lt;0.001), glucose (p=0.004), LDL (p=0.015), AST (p&amp;lt;0.001), ALT (p&amp;lt;0.026), CRP (p&amp;lt;0.001) levels and neutrophil count (p=0.003) were markedly higher in myocarditis group, HDL was lower (p&amp;lt;0.001). Conclusions: Although biochemical parameters display differences in myocarditis group, ECG findings did not differ.

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.

High risk of ventricular repolarization abnormalities among hemodialytic end-stage renal disease patients.

Patients with chronic renal disease (CKD) are at a significantly elevated risk for ventricular arrhythmia. Several electrocardiographic (ECG) methods can be used to assess the ventricular arrhythmia risk on the standard 12-lead ECG.

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.