The assessment of adolescent obesity's effects on ventricular repolarization.

BACKGROUND: Currently, there is a lack of research on the Tp-Te interval and Tp-e/QT ratio in obese adolescents who have metabolic syndrome. AIM: Our 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. METHODS: The 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. RESULTS: The 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. CONCLUSIONS: Obese 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.

Evaluation of ventricular repolarization in dermatomyositis and relationship with inflammation and autoimmunity.

Dermatomyositis (DM) is a chronic multi-systemic inflammatory disorder of autoimmune origin, which has been associated with cardiovascular complications, including ventricular arrhythmias and sudden cardiac death. The Tp-e interval and Tp-e/QT ratio have been accepted as new markers for the assessment of myocardial repolarization and ventricular arrhythmogenesis. The aim of this study was to evaluate ventricular repolarization by using Tp-e interval and Tp-e/QT ratio in patients with DM, and to assess the relation with inflammation and autoimmunity. This study included 281 DM patients (180 females, 101 males; mean age 52.73 ± 15.80 years) and 281 control subjects (180 females, 101 males; mean age 53.38 ± 15.72 years). QTc, Tp-e interval and Tp-e/QT ratio were measured from the 12-lead ECG. The plasma level of blood routine test, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) was measured. These parameters were compared between groups. No statistically significant difference was found between two groups in terms of basic characteristics. In electrocardiographic parameters analysis, QTc, Tp-e interval and Tp-e/QT ratio were significantly increased in DM patients compared to the control group (441.44 ± 26.62 ms vs 422.72 ± 11.7 ms, 104.16 ± 24.34 ms vs 77.23 ± 16.25 ms and 0.27 ± 0.06 ms vs 0.20 ± 0.04 ms, all P value < 0.01). QTc, Tp-e interval and Tp-e/QT were positively correlated with NLR, CRP, and ESR (all P values < 0.01), and were increased in anti-Ro/SSA-52kD positive patients compared to those negative (452.33 ± 24.89 ms vs 438.55 ± 26.37 ms, 114.05 ± 22.68 ms vs 101.53 ± 24.13 ms, and 0.29 ± 0.06 ms vs 0.27 ± 0.05 ms, all P value < 0.01). Our study demonstrated that QTc, Tp-e interval, and Tp-e/QT ratio were increased in DM patients and were associated with inflammatory markers and anti-Ro/SSA-52kD positivity.

Evaluation of Tpeak-end interval, Tpeak-end/QT, and Tpeak-end/Qtc ratio during acute migraine attack in the emergency department.

INTRODUCTION: During an acute migraine attack, changes in ventricular repolarisation parameters may occur due to an imbalance in the autonomic nervous system. Tpeak-tend (Tp-e) interval, Tp-e/QT ratio, and Tp-e/corrected QT (QTc) ratio are novel parameters of arrhythmogenesis and can be easily calculated in electrocardiography (ECG). The objective of this study is to demonstrate that novel ventricular repolarisation parameters can anticipate the risk of ventricular dysrhythmia in the migraine attack period. METHODS: This research was a prospective case-control study, which recruited a total of 144 participants, including 74 migraine patients and 70 healthy volunteers in the control group (CG) who met the criteria for migraine with or without aura. All participants underwent 12-lead ECG recordings, and the study compared the Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio with those of the CG. RESULTS: The average age of patients experiencing migraine attacks was 38.14 ± 10.82, with 58 (76%) of these patients being female. The Tp-e interval mean was higher in the migraine attack group than the CG, with a statistically significant difference discovered (74.22 ± 20.20 ms [ms] compared to 65.39 ± 11.33 ms, p = 0.001). However, there were higher mean Tp-e/QT and Tp-e/QTc ratios in the migraine attack group compared to the CG, and this difference was found to be statistically significant (0.20 ± 0.05 vs. 0.17 ± 0.03, p = 0.001, 0.18 ± 0.52 vs 0.16 ± 0.29, p = 0.003, respectively). CONCLUSION: Prolonged Tp-e interval and elevated Tp-e/QT and Tp-e/QTc ratios were observed in migraine patients who presented to the emergency department, indicating a potential risk of ventricular dysrhythmia.

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.

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

BACKGROUND: Dapagliflozin 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. AIM: The 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. METHOD: We 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. RESULTS: Among 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). CONCLUSION: Similar 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.

Cardio-ankle brachial index is associated with prolonged Tp-e interval in patients with arterial hypertension.

AIM: The cardio-ankle vascular index (CAVI) is a marker of arterial stiffness, and elevated CAVI values have been reported to be associated with an increased risk of cardiovascular mortality and cardiac arrhythmia. This study aimed to evaluate the relationship between Tp-e interval and CAVI, which is associated with cardiac arrhythmia on electrocardiography (ECG). METHOD: The study included patients with hypertension whose blood pressure values were taken under control with optimal medical treatment. Arterial stiffness and CAVI were measured using the vascular scanning system VaSera VS-1000. The patients were divided into two groups as CAVI<9 and CAVI≥9. Ventricular repolarization markers QT and QTc intervals, Tp-e interval, and Tp-e/QT and Tp-e/QTc ratios were measured using 12­lead ECG. RESULTS: Tp-e interval (78.7 ± 10.3 vs. 63.6 ± 9.1, p < 0.001), Tp-e/QT ratio (0.018 ± 0.02 vs. 0.015 ± 0.02, p < 0.001), and Tp-e/QTc ratio (0.17 ± 0.02 vs. 0.14 ± 0.04, p = 0.025) were statistically significantly higher in the CAVI≥9 group compared to the CAVI<9 group. In the prediction of patients in the CAVI≥9 group, Tp-e interval had an area under the curve value of 0.862 (0.784-0.940, p < 0.001) at the cut-off point of >72.5 msec, indicating a statistically significant result. Left CAVI and right CAVI were found to be significantly correlated with Tp-e interval (r = -0.650, p < 0.001 and r = -0.663, p < 0.001, respectively). CONCLUSION: We found that elevated CAVI values were associated and positively correlated with prolonged Tp-e interval values in patients with hypertension. Patients with elevated CAVI values should be followed up closely to prevent cardiac arrhythmic events.

Electrocardiographic Findings in Children With Growth Hormone Deficiency.

Introduction It has been shown that cardiac functions begin to deteriorate in growth hormone (GH) deficiency even in childhood. However, little is known about how GH deficiency affects arrhythmogenesis. The aim of this study was to evaluate the parameters of P wave dispersion (Pd), QT dispersion (QTd), corrected QT (QTc) dispersion (QTcd), T wave peak-to-end (Tp-e) interval, Tp-e/QT ratio, and Tp-e/QTc ratio in children with GH deficiency. This study also aimed to evaluate the relationship of these parameters with insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP-3). Method In the study, records of children diagnosed with GH deficiency in Adana City Training and Research Hospital Pediatric Endocrine Outpatient Clinic between September 2021 and December 2022 were retrospectively reviewed. The control group consisted of children in the same age group who applied to the Emergency Outpatient Clinic with a complaint of chest pain and no pathological finding was detected. The electrocardiograms (ECGs) of all patients were retrospectively evaluated. Results There were a total of 82 children in the study, 41 of whom were diagnosed with GH deficiency and 41 in the healthy control group. The age and male/female ratio of children with GH deficiency were similar to those in the control group (p>0.05). There were 27 (66%) children with complete GH deficiency and 14 (34%) children with partial GH deficiency. P wave dispersion was similar in both GH-deficient children and control group children. It was also similar in children with complete and partial GH deficiency (p>0.05). QT and QTc dispersions were found to be increased in children with GH deficiency, although not statistically significant, compared to the control group (p>0.05). Tp-e interval, Tp-e/QTmax (longest QT interval), and Tp-e/QTcmax (longest QTc interval) ratios were increased in children with GH deficiency compared to the control group (p=0.001, p=0.003, and p=0.001, respectively). QT and QTc dispersion, Tp-e interval, Tp-e/QTmax, and Tp-e/QTcmax ratios were found to be increased in children with complete GH deficiency compared to children with partial GH deficiency, but the difference was not significant (p>0.05). No correlation was found between these ECG parameters and IGF-1, IGFBP-3, and peak GH levels after stimulation tests (p>0.05). Conclusion We found in our study that the Tp-e interval was longer and Tp-e/QT and Tp-e/QTc ratios were increased in children with GH deficiency. These results suggest that the risk of ventricular arrhythmias in children with GH deficiency may start to increase from childhood. However, further prospective studies are needed to confirm our results.

The Tp-e/QT ratio as a predictor of nocturnal premature ventricular contraction events in patients with obstructive sleep apnea.

BACKGROUND: Obstructive sleep apnea (OSA) is significantly associated with a higher risk of ventricular arrhythmia (VA). QT, the Tp-e/QT ratio, and QT dispersion (QTd) are used to evaluate myocardial repolarization and are highly correlated with VA. The aim was to evaluate the predictive value of the Tp-e/QT ratio and other electrocardiogram (ECG) parameters for nocturnal premature ventricular contractions (PVCs) in patients with OSA. METHODS: We retrospectively analyzed data from patients with OSA and conducted a 1:1 matched cohort study. Patients diagnosed with OSA who met our criteria for the PVC group, and sex- and age-matched patients with OSA who met our criteria for the control group were enrolled in the study. The Tp-e, Tp-e/QT ratio, corrected QT interval (QTc), corrected Tp-e interval (Tp-ec), and QTd were measured, calculated and analyzed. RESULTS: Patients in the PVC group (n = 31) showed a greater Tp-e, Tp-ec, QTc, Tp-e/QT ratio, and QTd than patients in the control group (n = 31). In the univariate binary logistic regression analysis, higher Tp-ec (OR: 1.025; P = 0.042), QTc (OR: 1.014; P = 0.036), Tp-e/QT ratio (OR: 1.675; P < 0.001), and QTd (OR: 1.052; P = 0.012) values were all significantly associated with nocturnal PVCs. In multivariate analysis and receiver operating characteristic analysis, a higher Tp-e/QT ratio (OR: 2.168; 95% CI: 0.762-0.952; P < 0.001) was an independent predictor of nocturnal PVCs. CONCLUSIONS: The QTc, Tp-e/QT ratio, and QTd in patients with OSA with nocturnal PVCs were significantly increased compared with those in patients without nocturnal PVCs. A prolonged Tp-e/QT ratio was an independent predictor of nocturnal PVCs in patients with OSA.

Does the use of proton pump inhibitors in children affect ventricular repolarisation parameters?

Proton pump inhibitors are widely used agents in the treatment of dyspepsia, and their effects on ventricular repolarisation through ion channels are well-known. Our aim is to evaluate the change in ventricular repolarisation parameters on electrocardiogram before and after proton pump inhibitor treatment. This study included 69 patients who had symptoms such as burning stomach pain, bloating, nausea, and heartburn for at least 3 months. Electrolyte levels of the patients were measured before and after treatment, and 12-lead electrocardiograms were taken at the initial and 1st month follow-up visit. Heart rate, QT interval, corrected QT (QTc), QT dispersion (QTd), QTc dispersion (QTcd), Tp-e measurements, and Tp-e/QT ratio were calculated and compared. Thirty-nine of the patients were girls, 30 were boys, and the mean age was 13.16 ± 3.02 years. Electrolyte levels of the patients before and after treatment were within the normal range. There was no statistically significant difference in the QTc, the Tp-e duration, or the Tp-e/QT ratio of the patients before and after treatment. We did not find a significant prolongation in the QTc duration or any other ventricular repolarisation parameters after proton pump inhibitor treatment in children with dyspepsia. We did not observe ventricular arrhythmia in our patients during follow-up. However, different results might be obtained with a larger sample and a longer follow-up period. These patients may have an increased risk of developing ventricular arrhythmias. Therefore, precaution should be taken when using drugs that prolong the QT period, and follow-up with serial electrocardiograms should be planned.

The predictive value of electrocardiographic polarization parameters on appropriate ICD shock in primary prevention heart failure patients.

OBJECT: The effect of frontal QRS-T angle, Tp-e and Tp-e/QT ratio on cardiac events have been shown in many studies. In this study, we aimed to determine the prognostic value of frontal QRS-T angle, TPe and Tp-e/QT ratio on ICD shock in patients who had ICD (Implantable Cardioverter Defibrillator) implanted due to heart failure with reduced ejection fraction (HFrEF). MATERIAL AND METHOD: 158 patients with HFrEF who had previous ICD implantation were retrospectively analyzed. 27 patients were found to have an appropriate shock. Frontal QRS-T angle, Tp-e interval, Tp-e/QT ratio were calculated by evaluating the basal ECG records of the patients. Comparisons of these arrhythmogenic predictors were made in patients with and without ICD shock at follow-up. RESULT: When 158 patients with previous ICD implantation were analyzed in two groups with and without ICD shock, the number of patients with frontal QRS-T angle >120°, Tp-e interval > 105 ms, Tp-e/QT > 0.2 in the shock group (n: 27) was found to be high with a different significance (p:<0.01, p:<0.01, p:<0.01). There was no significant difference between the two groups regarding other ECG parameters such as QRS duration, QT interval, PR interval, fragmented QRS and positive T wave. In addition, more amiodarone use was observed in the shock group, and more hyperlipidemia cases were observed in the non-shocked group (p:0.01; p:<0.01). CONCLUSION: Increased frontal QRS-T angle, Tp-e interval, and Tp-e/QT ratio are arrhythmogenic parameters and predict appropriate ICD shock.

Are Tp-e interval and QT dispersion values important in children with coeliac disease?

OBJECTIVES: Coeliac disease is an autoimmune intestinal disease that develops with permanent intolerance to gluten and similar cereal proteins. It can damage to many tissues, including myocardium, by autoimmune mechanisms. In our study, we aimed to investigate the effect of coeliac disease on cardiac electrical activity by comparing the Tp-e interval and Qt dispersion values of coeliac patients with healthy children. METHODS: Fifty-seven coeliac patients and 57 healthy children were included in the study. Sociodemographic findings, physical examinations, symptoms, laboratory values, dietary compliance, endoscopy, and pathological findings were recorded into a standardised form. Electrocardiogram parameters were calculated, and echocardiography findings were noted. RESULTS: No statistically significant difference was found between the two groups in terms of age, gender, heart rate, electrocardiogram parameters such as p wave, PR interval, QRS complex, QT interval, and QTc values. Tp-e interval, Tp-e / QT ratio, and Tp-e / QTc ratio were statistically significantly higher in the patient group compared to the control group. Ejection fraction and fractional shortening values were significantly lower in the patient group compared to the control group. In the patient group, Tp-e interval, Tp-e / QT ratio, Tp-e / QTc ratio, and QTc dispersion were statistically significantly higher in patients with tissue transglutaminase IgA positive compared to patients with tissue transglutaminase IgA negative. CONCLUSION: Our study gives important findings in terms of detecting early signs of future cardiovascular events in childhood age group coeliac patients.

Assessment of Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios in patients with acromegaly.

BACKGROUND: Cardiovascular complications, including ventricular arrhythmias associated with abnormalities of ventricular repolarization, are the leading cause of morbidity and mortality in patients with acromegaly. Herein, we aimed to investigate ventricular repolarization using Tp-e interval, Tp-e interval/QT, and Tp-e interval/QTc ratios in acromegalic patients compared to healthy subjects. METHODS: A total of 29 patients (aged 51.9 ± 11.2, 65.5% women) with acromegaly and 30 control subjects (aged 47.3 ± 14.4, 63.3% women) were enrolled in the study. Tp-e and QT interval, corrected QT (QTc), Tp-e/QT, and Tp-e/QTc ratios were calculated from the 12-lead electrocardiogram. RESULTS: Tp-e interval (89.28 ± 12.16 vs. 75.97 ± 9.92 ms; p < 0.001), Tp-e/QT ratio (0.237 ± 0.045 vs. 0.212 ± 0.029; p = 0.019), and Tp-e/ QTc ratio (0.218 ± 0.031 vs. 0.195 ± 0.026; p = 0.003) were significantly higher in patients with acromegaly compared to control group. A positive correlation was determined between left atrial volume index (LAVI) and Tp-e interval (r = 0.272, p = 0.039). DISCUSSION: The current study is the first to have shown significantly increased Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio were increased in acromegalic patients. These results may be important for screening malignant arrhythmic events in acromegaly.

Effect of Sodium-Glucose Co-transporter-2 Inhibitors on Ventricular Repolarization Markers in Heart Failure with Reduced Ejection Fraction.

BACKGROUND AND AIM: Sodium-glucose co-transporter-2 (SGLT2) inhibitors added to optimal medical therapy have been shown to reduce the risk of cardiovascular death and recurrent heart failure (HF) hospitalization in HF patients. We aimed to evaluate the effect of SGLT2 inhibitors on the ventricular repolarization markers (VRM) in patients with HF with reduced ejection fraction (HFrEF). METHODS: 51 patients with HFrEF who had symptoms New York Heart Association (NYHA) class II-IV despite optimal medical treatment and were added SGLT2 inhibitors to their treatment were included in the study. Electrocardiography (ECG) and laboratory results obtained before the treatment and at the first-month follow-up visit were compared. QT, QTc (corrected by Bazett formula), QT dispersion (QTd), QTc dispersion (QTc-d), Tpeak to Tend (Tp-e) interval, Tp-e/QT, and Tp-e/QTc ratios were measured and defined as VRM. RESULTS: A significant decrease was observed in HR, QT, QTc intervals, and QTd compared to pre-treatment. While the mean Tp-e interval was 101.5 ± 11.7 ms before treatment, it decreased to 93.1 ± 12.7 ms after treatment (p < 0.001). There was a significant decrease in N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels after treatment [2859 ± 681vs.1266 ± 763, respectively (p < 0.001)] and QTd, Tp-e interval, and Tp-e/QTc ratio was positively correlated with the change in NT-proBNP level. CONCLUSIONS: The addition of SGLT2 inhibitors to optimal medical therapy in HFrEF patients positively changes VRM (QT, QTc, QTd, Tp-e, and Tp-e/QTc).

Correlation between frontal QRS-T angle, Tp-e interval, and Tp-e/QT ratio to coronary artery severity assessed with SYNTAX score in stable coronary artery disease patients.

Background: It is known that a wide frontal QRS-T(f[QRS-T]) angle in the electrocardiography (ECG) is associated with poor cardiovascular outcomes. The Tp-e (the interval from the peak to the end of the T wave) interval and Tp-e/QTc ratio show the dispersion of repolarization, and increased levels lead to ventricular arrhythmogenesis in congenital channelopathies and coronary heart disease. In this study, we aimed to investigate the relationship between f(QRS-T), Tp-e interval, and Tp-e/QTc ratio and SYNTAX score in stable coronary artery disease (SCAD) patients. Methods: A total of 403 patients who performed coronary angiography for SCAD were included. The study population was divided into two groups based on the SYNTAX score. Group 1 included 248 patients (high SYNTAX score > 0), and group 2 included 155 patients (low SYNTAX score = 0). SYNTAX score was calculated using an online SYNTAX score calculator from the coronary angiography images of each patient. The f(QRS-T) angle (QRS angle minus T angle) was calculated from the automated reports of the 12-lead ECG device. Tp-e interval and Tp-e/QTc ratio and other electrocardiographic parameters were recorded. Results: The mean SYNTAX score in group 1 was 8. F(QRS-T) angle, Tp-e duration, Tp-e/QT, and Tp-e/QTc were significantly higher in group 1 compared with group 2. In the multivariate regression analysis, F(QRS-T) angle and Tp-e duration were independent predictors for SYNTAX scores in SCAD patients. Conclusions: Our study showed that Tp-e interval, Tp-e/QTc ratio, and f(QRS-T) angle were increased in patients with higher SYNTAX scores in patients with SCAD patients.

Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios in patients with primary hyperparathyroidism and their relationship with cardiac arrhythmic events.

BACKGROUND: Primary hyperparathyroidism (PHPT) is an endocrine disorder characterized by hypercalcemia caused by excessive parathyroid hormone (PTH) secretion from the parathyroid gland. PHPT was previously shown to increase cardiac arrhythmias. Besides, new indices, such as the Tpeak-Tend (Tp-e) interval, Tp-e interval/QT interval (Tp-e/QT) ratio, and Tp-e interval/corrected QT interval (Tp-e/QTc) ratio may be associated with ventricular arrhythmias and sudden cardiac death. Therefore, we aimed to investigate the relationship between PHPT and the changes to Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio. METHODS: We carried out the study with 41 patients with PHPT and 40 control subjects. We calculated the Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio of the participants from the V5 derivations on their ECG papers. While we defined Tp-e interval as the distance between the peak and the end of the T wave, Tp-e/QT and Tp-e/QTc ratios were calculated by dividing Tp-e by QT and Tp-e by QTc, respectively. RESULTS: Total calcium, albumin-corrected calcium, phosphorus, and PTH levels were significantly higher in patients with PHPT. We also found positive correlations between albumin-corrected calcium and PTH levels and Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio (p < 0.001). DISCUSSION: : Our results suggest that Tp-e may enhance the current knowledge on arrhythmic risk in PHPT patients better than basal ECG. In addition, both high PTH and high calcium levels appear to have the potential to cause arrhythmogenic effects.

Association of Tp-e/QT ratio with SYNTAX score II in patients with coronary artery disease.

Background. The SYNTAX score II (SS) is an angiographic tool, which grades the complexity of coronary artery lesions and predicts short- and long-term events. Tp-e/QT ratio is a novel electrocardiographic marker for the risk of ventricular arrhythmias. We aimed to investigate whether there was a correlation between SS and Tp-e/QT ratio.Methods. A total of 227 consecutive patients who underwent elective coronary angiography were enrolled in this study. Patients who had a lumen diameter >1.5 mm and at least % 50 diameter stenosis on coronary angiogram were determined as coronary artery disease (CAD) group, and others were identified as a control group. The SS was calculated for the CAD group, and SS ≥23 was defined as a high SS group, and SS < 23 was identified as a low SS group. Electrocardiographic indices, such as Tp-e and Tp-e/QT, were measured for all patients. A multivariable logistic regression analysis was performed with variables age, interventricular septum thickness (IVS), hypertension, and Tp-e/QT. Results. Tp-e interval and Tp-e/QT ratio were higher in the CAD group compared with the control group. Tp-e, corrected Tp-e (cTP-e) and Tp-e/QT were higher in the high SS group than in the low SS group. The cTp-e and Tp-e/QT were correlated with SS score. Age, IVS and Tp-e/QT ratio were independent predictors of high SS in the logistic regression analysis. Conclusions. Tp-e/QT ratio was an independent predictor of high SS and might be used for risk stratification in CAD patients.

Optimizing ECG lead selection for detection of prolongation of ventricular repolarization as measured by the Tpeak-end interval.

BACKGROUND: The Tpeak-end(Tp-e) has not been compared in all 12 ECG leads in healthy adults to determine if the Tp-e varies across leads. If there is variation, it remains uncertain, which lead(s) are preferred for recording in order to capture the maximal Tp-e value. OBJECTIVE: The purpose of the current study was to determine the optimal leads, if any, to capture the maximal Tp-e interval in healthy young adults. METHODS: In 88 healthy adults (ages 21-38 years), including derivation (n = 21), validation (n = 20), and smoker/vaper (n = 47) cohorts, the Tp-e was measured using commercial computer software (LabChart Pro 8 with ECG module, ADInstruments) in all 12 leads at rest and following a provocative maneuver, abrupt standing. Tp-e was compared to determine which lead(s) most frequently captured the maximal Tp-e interval. RESULTS: In the rest and abrupt standing positions, the Tp-e was not uniform among the 12 leads; the maximal Tp-e was most frequently captured in the precordial leads. At rest, grouping leads V2-V4 resulted in detection of the maximum Tp-e in 85.7% of participants (CI 70.7, 99.9%) versus all other leads (p < .001). Upon abrupt standing, grouping leads V2-V6 together, resulted in detection of the maximum Tp-e 85.0% of participants (CI 69.4, 99.9% versus all other leads; p < .001). These findings were confirmed in the validation cohort, and extended to the smoking/vaping cohort. CONCLUSION: If only a subset of ECG leads will be recorded or analyzed for the Tp-e interval, selection of the precordial leads is preferred since these leads are most likely to capture the maximal Tp-e value.

Effects of azithromycin on ventricular repolarization in children with COVID-19.

Introduction: Azithromycin is used to treat pediatric COVID-19 patients. It can also prolong the QT interval in adults. This study assessed the effects of azithromycin on ventricular repolarization in children with COVID-19. Method: The study prospectively enrolled children with COVID-19 who received azithromycin between July and August 2020. An electrocardiogram was performed before, one, three, and five days post-treatment. Using ImageJ®, the following parameters were measured: QT max, QT min, Tp-e max, and Tp-e min. The parameters QTc max, QTc min, Tp-ec max, Tp-ec min, QTcd, Tp-ecd, and the QTc/Tp-ec ratio were calculated using Bazett's formula. Results: The study included 105 pediatric patients (mean age 9.8±5.3 years). The pretreatment heart rate was higher than after treatment (before 92 [79-108]/min vs. Day 1 82 [69-108)]/min vs. Day 3 80 [68-92.2]/min vs. Day 5 81 [70-92]/min; p=0.05). Conclusion: Azithromycin does not affect the ventricular repolarization parameters on ECG in pediatric COVID-19 cases.

Introdução: A azitromicina (AZ) é utilizada no tratamento da COVID-19 em pediatria. Como este fármaco pode prolongar o intervalo QT nos adultos, este estudo avaliou os efeitos da AZ na repolarização ventricular de crianças com COVID-19. Método: Este estudo prospetivo incluiu crianças com COVID-19 que foram tratadas com AZ em julho-agosto 2020. Foi efetuado um eletrocardiograma (ECG) antes e um, 3 e 5 dias após o tratamento. Utilizando ImageJ ®, foram medidos os parâmetros seguintes: QT max, QT min, Tp-e max, e Tp-e min. Os parâmetros QTc min, Tp-ec max, Tp-ec min, QTcd, Tp-ecd e QTc/Tp-ec ratio foram calculados utilizando a fórmula Bazett. Resultados: O estudo incluiu 105 doentes pediátricos (idade média 9,8±5,3 anos). A frequência cardíaca no pré-tratamento foi mais elevada do que após o tratamento (antes 92 [79­108]/min versus dia 1 82 [69­108)]/min versus dia 3 80 [68­92,2]/min versus dia 5 81 [70­92]/min; p=0,05). Conclusão: A AZ não afeta os parâmetros de repolarização ventricular no ECG nos casos pediátricos da COVID-19.

Effect of levetiracetam on cardiac repolarization in children with epilepsy.

INTRODUCTION: Epileptic discharges occurring during seizure may affect many systems in the ictal, postictal, and interictal periods. Autonomic dysfunction and its negative impacts on the heart may cause life-threatening clinical manifestations, cardiac arrhythmias, and sudden cardiac death in epileptic patients. This study investigated the impact of levetiracetam (LEV) therapy on cardiac electrical activity in children with epilepsy. MATERIAL AND METHODS: Our study included a total of 120 cases, comprising 40 newly diagnosed epilepsy patients, 40 epilepsy patients who had been receiving LEV therapy for at least 6 months, and 40 healthy individuals. Age at diagnosis, duration of LEV treatment, and familial history of cardiac disease were recorded in a standardized form. Electrocardiogram (ECG) parameters were calculated for all cases, echocardiography (ECHO) findings were noted, and the obtained data were compared using statistical methods. RESULTS: A comparison of the ECG parameters showed that the Tpeak-Tend (Tp-e) interval, and the Tp-e/QT dispersion (QTd) and Tp-e/QTc dispersion (QTcd) ratios, of the newly diagnosed epilepsy patients were statistically significantly increased compared with the other two groups (p = <0.001, p = 0.001, and p = 0.007, respectively). There were no statistically significant differences between the three groups in terms of QTd and QTcd. DISCUSSION: The repolarization differences in children with newly diagnosed epilepsy may have reflected early subclinical findings associated with the disease. We concluded that LEV monotherapy may make a positive contribution to early repolarization differences.

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.