Ventricular Repolarization Parameters Research Articles

T-wave peak-end interval and ratio of T-wave peak-end and QT intervals: novel arrhythmogenic and survival markers for dogs with myxomatous mitral valve disease

Introduction/objectivesIn the past few years, novel markers such as the interval between the peak and the end of T-wave (Tpte) and Tpte/QT ratio have been shown to have high sensitivity for ventricular arrhythmias and mortality. We analyzed these and other parameters of ventricular repolarization, such as QT interval, QT interval corrected for heart rate (QTc), and QT dispersion (QTd) in dogs with myxomatous mitral valve disease (MMVD). Additionally, we investigated their relationship with the progression of the disease, echocardiographic parameters, and ventricular arrhythmias and assessed their prognostic value with development of clinical signs or mortality as the final outcome. Animals, materials and methodsEpidemiological, clinical, echocardiographic, and electrocardiographic data were obtained from 236 dogs with MMVD and 15 healthy dogs. Prognostic and survival information was also recorded for the MMVD group. All ventricular repolarization indices were measured in 10 lead electrocardiographic recordings. ResultsWith the exception of the QT interval, most repolarization markers increased along with the frequency of arrhythmias and with the progression of MMVD. The parameters that best identified ventricular arrhythmias (AUC > 0.7) were Tpte (aVR, rV2, average rV2–V10, average rV2–V4) and Tpte/QT (II, aVR, rV2). In survival analysis, statistically significant markers with the highest differences in median survival were Tpte (maximum of any lead, maximum rV2–V10), QTc aVR, and Tpte rV2. ConclusionTpte and Tpte/QT are good non-invasive markers for clinical risk stratification in dogs with MMVD.

Tp-Te interval prolongs in hypertension independent of the left ventricular geometry

Background/Aim: Hypertension (HT) may modulate left ventricular (LV) geometry. Electrocardiographic Tp-Te, QT and QTc interval, and Tp-Te/QTc ratio are among the parameters of ventricular repolarization (VR) that may predict ventricular arrhytmogenic potential and possess prognostic significance. It is well known that left ventricular hypertrophy is associated with increase in the parameters of VR; however, little is known about the association of these parameters with other forms of LV geometry in HT. Our aim was to assess this association. Methods: A total of 162 newly diagnosed essential HT patients were enrolled and divided into those with concentric LV remodeling (n=79) and those with normal LV geometry (n=83). Healthy normotensive subjects (n=76) comprised the control group. Data were gathered retrospectively from electrocardiographic, echocardiographic, and demographic records. Results: QT interval, P-wave duration, and QRS duration were similar among the 3 groups (P>0.05). Tp-Te, QTc and Tp-Te/QTc were greater in the HT group compared with the controls (P 0.05). There was no correlation between Tp-Te interval, LV mass and LV mass index among the study population. Conclusion: Tp-Te may be useful in prognostic stratification of HT. Regardless of the LV geometry, HT patients have prolonged Tp-Te and QTc intervals, and increased Tp-Te/QTc ratio compared to the healthy subjects. Our findings may suggest possible utilization of Tp-Te as HT-related end-organ damage in the future.

Cardiovascular risk assessment in children and adolescents with congenital solitary kidneys.

Patients with solitary kidneys (SKs) are at risk of hypertension (HT) and associated end‐organ damage. The authors aimed to evaluate whether children with congenital SKs (CSKs) have higher office, ambulatory, or central blood pressure (BP), increased arterial stiffness or left ventricular mass index, or any risk for arrhythmia. With this purpose, patients with CSK and healthy controls being followed up between January 2018 and June 2019 were enrolled in the study. Demographic, biochemical, and office blood pressure (BP) data were recorded. Then, ambulatory blood pressure monitoring (ABPM) and measurements of central BP (cBP), pulse wave velocity (PWV), and augmentation index (AIx@75) were obtained. Ventricular repolarization parameters were acquired by 12‐lead electrocardiography. Left ventricular mass index (LVMI) and abdominal aortic stiffness parameters including strain, pressure strain elastic modulus (Ep), and normalized Ep (Ep*) were calculated with echocardiographic measurements. Finally, 36 children with CSK and 36 healthy controls were included. Serum creatinine, uric acid, total cholesterol levels, ABPM parameters, cBP levels, and PWV values were significantly higher, and eGFR levels were significantly lower in the CSK group. VR parameters, abdominal aortic stiffness indices, and LVMI were similar between the groups. CSK increased the risk of HT in ABPM (HTABPM) by 6 times. PWV was significantly correlated with Ep and Ep* in cases with CSK. Determination of cBP and PWV along with 24‐hour ABPM would be a useful tool in children with CSK.

The prognostic value of T-peak T-end among patients with implantable cardiac defibrillator for secondary prevention

Aim: Cardiac death due to ventricular arrhyhtmias can occur in patients with ICD (implantable cardioverter defibrillator) for secondaryprevention. The aim of this study is to assess the prognostic value of electrocardiographic ventricular repolarization parameters inpatients with secondary prevention.Materials and Methods: Sixty five patients with ICD for secondary prevention after sustained ventricular tachycardia, ventricularfibrillation or sudden cardiac death were enrolled to the study retrospectively. Patients were divided into groups according tomortality during a follow up period of 4,5 years (48 patients alive and 17 dead). Heart rate, QT, QTc and T peak T end (Tp-e) durationwere measured from 12 derivations ECG electronically.Results: Mean age of the study population was 70.6±11.9 years. Ventricular repolarization parameters such as QT, QTc, Tp-e durationand Tp-e index values were found to be similar between deaths and live patient groups. Patients who died during the follow-up hadadvanced age (68.7±12.5 vs 76.8±10.3 years, p=0.009), lower left ventricular ejection fraction percentage (LVEF %) (37.6±13.3 vs26.9±9.2, p=0.003) and lower estimated glomerular filtration rate (81.2±22.5 vs 61±34.3 ml/min/m2, p=0.03). Arrhythmic deathpatients only had lower LVEF % than non-arrhythmic death patient’s group.Conclusions: In patients with ICD for secondary prevention QT, QTc, Tp-e duration and Tp-e index were not related to mortality.

Association between Ventricular Repolarization Parameters and Cardiovascular Death in Patients of the SWISS-AF Cohort

Association between Ventricular Repolarization Parameters and Cardiovascular Death in Patients of the SWISS-AF Cohort

Effects of serum vitamin D level on ventricular repolarization in children and adolescents.

Low levels of vitamin D are known to increase cardiovascular mortality due to different risks. We aimed to examine whether low vitamin D levels in children and adolescents cause ventricular repolarization changes. Sixtyseven healthy cases aged between 3.5 and 17 years were included. According to levels of vitamin D, cases were grouped as sufficient (n=44), insufficient (n=13) and deficiency (n=10). Ventricular repolarization parameters were measured manually. Levels of vitamin D were different for cases with insufficiency and deficiency compared to sufficiency ones (102±54.9 vs 24.4±7 ng/ml, p<0.001 and 102±54.9 vs 16.6±8.3 ng/ml, respectively, p<0.001). In the insufficient group the following parameters were different from sufficient group: QTmean (357.8±25.3 vs 332±29.9 ms, p=0.012), JTc (310.8±20.2 vs 331.6±21 ms, p=0.005) and Tpe/QT (0.2±0.02 vs 0.22±0.02, p=0.02). It was found that the level of serum vitamin D correlated with JTc (r=-0.37, p=0.002), Tp-e (r=-0.29, p=0.015) and Tp-e/QT (r=-0.24, p=0.047). In the linear regression analysis, it was found that dropping level of vitamin D below normal was an independent risk factor for prolonged duration of JTc (p=0.015). Decline in vitamin D levels causes ventricular repolarization anomaly. As the decrease in vitamin D levels deepens, repolarization times become longer. These results could indicate that decrease in vitamin D levels can increase sensitivity to ventricular arrhythmias (Tab. 3, Ref. 45). Text in PDF www.elis.sk Keywords: adolescent, arrhythmia, child, vitamin D, ventricular repolarization.

Ventricular arrhythmias in mitral valve prolapse syndrome and their relationship with electrocardiographic repolarization parameters.

The aim of present study is to compare ventricular and supraventricular arrhythmia incidences in subjects with and without mitral valve prolapse (MVP) syndrome and to examine if an association exists between ventricular arrhythmias and repolarization parameters in patients with MVP syndrome. This cross-sectional study involved 41 subjects with MVP Syndrome and 41 subjects with palpitation but without MVP (control group). All subjects were subjected to lead-electrocardiogram, transthoracic echocardiography, and 24-h Holter monitoring to identify repolarization abnormalities, structural abnormalities, and supraventricular and ventricular arrhythmias. The QRS width, QTC interval, and Tpeak-Tend intervals were measured for each participant. The number of subjects who had premature ventricular contractions (PVCs), couplets, and non-sustained ventricular tachycardia (NSVTs) was significantly higher in the MVP group compared to the control group. Left ventricular end-systolic diameter (LVESD) and left ventricular end-diastolic diameter (LVEDD) and left atrial diameter were also significantly higher in the MVP group than the control group. QRS width and Tpeak-Tend interval were also significantly higher in subjects with MVP than the controls. Correlation analysis showed a positive correlation between the severity of mitral regurgitation (MR) and the number of PVCs and couplets, while there was a significant correlation between left atrium (LA) diameter and the number of the PVCs and NSVTs. Subjects with MVP experience ventricular arrhythmias more often including PVCs, couplets, and NSVTs compared to subjects without MVP. LVESD, LVEDD, LA diameter, QRS width, and Tpeak-Tend interval were increased in MVP subjects than those without MVP. There is an association between the severity of the MR and the frequency of the PVCs, couplets, or NSVTs.

Ventricular Repolarization Parameters In Hospitalized Patients With COVID-19

Objective: Coronavirus disease-2019 (COVID-19) may cause atrial and/or ventricular arrhythmias and sudden cardiac deaths, especially in severe cases. In this study, we aimed to investigate whether COVID-19 affects the ventricular repolarization parameters. Materials and Methods: In this study, 152 hospitalized patients with COVID-19 were included retrospectively. Age and sex-matched 151 healthy subjects were assigned as the control group. QT, QTc, Tpe, Tpe/QT, and Tpe/QTc values of all participants were determined and compared between both groups. The relationship between high sensitive-troponin I (hsTnI) and the parameters mentioned was analyzed using the Spearman correlation test. Results: Mean age, male gender and comorbidity rates were similar in both groups (p>0.05 for each). Heart rate, QTc, Tpe, Tpe/QT, and Tpe/QTc values were higher in the study group (p 0.05 for each). There were positive correlations between hsTnI and QT (rho=0.218, p=0.008), QTc (rho=0.308, p<0.001), Tpe (rho=0.646, p<0.001), Tpe/QT (rho=0.571, p<0.001), and Tpe/QTc (rho=0.608, p<0.001). Conclusion: In patients with COVID-19, QTc, Tpe, Tpe/QT, and Tpe/QTc values are higher than the control group and these parameters correlate positively with hsTnI. Therefore, ECG follow-up may be beneficial in preventing arrhythmic events, especially in patients with acute cardiac injuries. [ FROM AUTHOR] Copyright of Erciyes Medical Journal / Erciyes Tip Dergisi is the property of KARE Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all Abstracts.)

Comparison of ventricular repolarization parameters including Tp-e, Tp-e/QTc, JTc and JTd during low-flow and high-flow desflurane anesthesia in gynecologic laparoscopic surgery

Objectives: Low-flow anesthesia (LFA) gained reasonable popularity as it provides many advantages including physiological, ecological, economical issues. Desflurane is a preferable anesthetic in low-flow anesthesia practice however, the relation between QTc, QTd, and QTcd prolongation and management of anesthesia with desflurane has been previously demonstrated. We aimed to compare the effects of low-flow (LFA) and high-flow (HFA) desflurane anesthesia on hemodynamic changes and ventricular repolarization markers in gynecologic laparoscopy.&#x0D; Methods: 58 patients were randomized into group L (LFA, n=30) and group H (HFA, n=28). ECG was recorded before anesthesia and 60th minute of anesthesia in both groups.&#x0D; Results: JTc-0 values were lower than JTc-1 values within both group L and H (p=0.001 for both groups). JTcd-0 and JTd-1 values were lower than JTcd-1 within group H (p=0.042 and 0.002, respectively). QTc-0 values were lower than QTc-1 within both group L and group H (p=0.001 and 0.002, respectively). QTcd-0 values were lower than QTcd-1 within group H (p=0.021). QTd-0 values were lower than QTd-1 within-group H (p=0.026). Tpe-0 and Tpe-1 values were lower in group L (p=0.001 and 0.002 respectively). Also, JTc-0 values were lower than JTc-1 values within both group L and H (p=0.021 and 0.027, respectively). Tpe/QTc-1 ratio was significantly lower in group L (p= 0.010). The difference between Tpe/QTc-0 and Tpe/QTc-1 ratios within group H was significant (p=0.028).&#x0D; Conclusion: Our study showed that there was no significant difference between LFA and HFA in terms of ECG repolarization markers, which may predict the possibility of torsadogenity.

The bradycardic agent ivabradine decreases conduction velocity in the AV node and in the ventricles in-vivo

Ivabradine blocks hyperpolarisation-activated cyclic nucleotide-gated (HCN) channels, thereby lowering the heart rate, an action that is used clinically for the treatment of heart failure and angina pectoris. We and others have shown previously that ivabradine, in addition to its HCN channel blocking activity, also inhibits voltage-gated Na channels in vitro at concentrations that may be clinically relevant. Such action may reduce conduction velocity in cardiac atria and ventricles.Here, we explore the effect of administration of ivabradine on parameters of ventricular conduction and repolarization in the surface ECG of anesthetized mice. We found that 5 min after i.p. administration of 10 mg/kg ivabradine spontaneous heart rate had declined by ~13%, which is within the range observed in human clinical studies. At the same time a significant increase in QRS duration by ~18% was observed, suggesting a reduction in ventricular conduction velocity. During transesophageal pacing at heart rates between 100 and 220 beats/min there was no obvious rate-dependence of ivabradine–induced QRS prolongation. On the other hand, ivabradine produced substantial rate-dependent slowing of AV nodal conduction. We conclude that ivabradine prolongs conduction in the AV-node and in the ventricles in vivo.

Acute effects of electronic cigarette smoking on ventricular repolarization in adults.

Electronic cigarette (e-cigarette) use is constantly increasing. However, the association between e-cigarette use and ventricular arrhythmia is unknown. Thus, in this study, we aimed to evaluate the markers of ventricular repolarization such as QT interval, corrected QT (QTc), QT dispersion (QTd), peak-to-end interval of the T wave (Tp-e), corrected Tp-e and Tp-e/QT ratios in e-cigarette users. The study population consisted 36 e-cigarette users and 40 healthy subjects. Ventricular repolarization parameters were obtained from 12-lead resting electrocardiogram. Ventricular repolarization parameters of the groups were compared. Basal demographic and laboratory data were similar in both groups. According to the electrocardiographic parameters, the Tp-e interval, corrected Tp-e, and Tp-e/QT ratio were significantly higher in individuals using e-cigarettes than in control subjects [74.9±6.4 milliseconds (ms) vs. 80.1±4.1ms, <0.001; 82.9±7.5 ms vs. 87.8±6.3 ms, p=0.003; 0.20±0.01 vs. 0.21±0.01, p=0.002; respectively]. This is the first study to show the disruption of ventricular repolarization properties in e-cigarette users. E-cigarette use in terms of public health leads to augmentation of transmural dispersion of repolarization, which may be potential indicator of ventricular arrhythmogenesis.

Evaluation of early electrocardiographic changes after successful percutaneous stent implantation to isolated coarctation of aorta

BackgroundCoarctation of aorta (CoA) is a congenital obstructive lesion characterized by narrowing of the aorta in which concludes as increase in afterload. Percutaneous stent implantation to CoA is a treatment of choice in older children and adults. Pathology related to CoA mainly caused by increased afterload and left ventricular hypertrophy. Electrocardiographic (ECG) findings are also related to left ventricular hypertrophy (LVH). Evidence shows that, in variety of diseases, the correction of the pathology might normalize ECG findings and ventricular dysfunction related to increase in afterload. Therefore the aim of this study was to compare the pre- and postprocedural ECG findings of the patients who underwent percutaneous intervention for isolated CoA. MethodsAfter exclusion criterion was applied, 30 patients were included into study, retrospectively. ECG records before the procedure and 3 months after the procedure of the patients were evaluated. The parameters related to LVH, ventricular and atrial conduction were evaluated and compared between pre- and post-procedural ECG records. ResultsThe findings showed that parameters of atrial conduction including P wave maximum duration (p < 0.001) and p wave dispersion (p < 0.001) were significantly decreased after stent implantation. Additionally, ventricular repolarization parameters including QT duration (p = 0.039), Tpe interval (p < 0.001), Tpe / QT (p = 0.038) and Tpe / QTc (p = 0.003) were significantly decreased after stent implantation. Sokolow-Lyon criteria (p < 0.003) and voltage in selected leads were significantly decreased after intervention. ConclusionPercutaneous intervention to CoA might regress LVH parameters in ECG and improve atrial and ventricular repolarization in ECG, which might lead to decreased event of atrial and ventricular arrhythmias in patients with isolated CoA.

Impaired repolarization parameters may predict fatal ventricular arrhythmias in patients with hypertrophic cardiomyopathy (from the CILICIA Registry)

BackgroundHypertrophic cardiomyopathy (HCM) is significantly associated with high risk of fatal ventricular arrhythmias (VAs). Increased frontal QRST angle (fQRSTa), Tpe interval, and Tp-e/QTc ratio are described as ventricular repolarization parameters which are related to arrhythmias. In this study, we aimed to investigate the predictive value of these repolarization parameters for fatal VAs in patients with HCM. MethodsA total of 127 HCM patients (mean age: 47.9 ± 12.6 years; male:79) were enrolled in this retrospective study. All patients underwent transthoracic echocardiography. Moreover, the last electrocardiograms within 3 months prior to the fatal VA documentation were assessed. The primary outcome was the occurrence of fatal VAs including sustained ventricular tachycardia and ventricular fibrillation which were documented from implantable cardioverter defibrillator records. ResultsThere were documented fatal VAs in 37 (29.1%) patients during a mean follow-up time of 70.1 ± 22.6 months. The prevalence of fatal VAs was significantly higher in patients with fQRSTa ≥140 degrees (67.4 vs. 7.4%; p < 0.001) and in patients with Tp-e/QTc ratio ≥ 0.19 (61.5 vs. 6.7%; p < 0.001) as compared to others. High Tp-e/QTc ratio (hazard ratio: 1.564; 95% confidence interval: 1.086–4.796; p = 0.032) and high fQRSTa (hazard ratio: 1.864; 95% confidence interval: 1.106–8.745; p = 0.002) were found to be independent predictors of fatal VAs in HCM patients. ConclusionsWider fQRSTa, prolonged Tp–e interval, and increased Tp–e/QTc ratio may be associated with fatal VAs in HCM patients. In addition to traditional risk factors, these simple ECG parameters may provide valuable information during evaluation of sudden cardiac death risk in HCM patients.

Association of Mild Hyperbilirubinemia with Decreased ECG-Based Ventricular Repolarization Parameters in Young Men.

Hyperbilirubinemia is associated with protection against various oxidative stress-mediated diseases. We aimed to investigate the association between bilirubin and novel electrocardiography (ECG)-based ventricular repolarization parameters. We enrolled 201 healthy men with mild hyperbilirubinemia (group 1) and 219 healthy men with normal bilirubin levels (group 2). The Tpeak-Tend (Tp-e) interval (defined as the interval from the peak of the T wave to the end of the T wave), corrected (c) Tp-e interval, QT interval, cQT interval, and Tp-e interval/QT interval ratio were measured from leads V5 and V6 with 20 mm/mV amplitude and 50 mm/second rate. The Tp-e interval, cTp-e interval, and Tp-e interval/QT interval ratio were significantly lower in group 1 compared with group 2. The cTp-e interval showed a significant negative correlation with total bilirubin, conjugated bilirubin, and unconjugated bilirubin. The cTp-e interval (odds ratio [OR], 0.900; P =.002) and Tp-e interval/QT interval ratio (OR, 0.922; P =.04) were significantly associated with mild hyperbilirubinemia. We showed the association of mild hyperbilirubinemia with decreased novel ECG-based ventricular repolarization parameters.

Evaluation of electrocardiographic markers of cardiac arrhythmic events and their correlation with cardiac iron overload in patients with β-thalassemia major.

Iron overload is associated with an increased risk of atrial and ventricular arrhythmias. Data regarding the relationship between electrocardiographic parameters of atrial depolarisation and ventricular repolarisation with cardiac T2* MRI are scarce. Therefore, we aimed to investigate these electrocardiographic parameters and their relationship with cardiac T2* value in patients with β-thalassemia major. In this prospective study, 52 patients with β-thalassemia major and 52 age- and gender-matched healthy patients were included. Electrocardiographic measurements of QT, T peak to end interval, and P wave intervals were performed by one cardiologist who was blind to patients' data. All patients underwent MRI for cardiac T2* evaluation. Cardiac T2* scores less than 20 ms were considered as iron overload. P wave dispersion, QTc interval, and the dispersions of QT and QTc were significantly prolonged in β-thalassemia major patients compared to controls. Interestingly, we found prolonged P waves, QT and T peak to end dispersions, T peak to end intervals, and increased T peak to end/QT ratios in patients with T2* greater than 20 ms. No significant correlation was observed between electrocardiographic parameters and cardiac T2* values and plasma ferritin levels. In conclusion, our study demonstrated that atrial depolarisation and ventricular repolarisation parameters are affected in β-thalassemia major patients and that these parameters are not correlated with cardiac iron load.

Clinical Implications of Ventricular Repolarization Parameters on Long-Term Risk of Atrial Fibrillation - Longitudinal Follow-up Data From a General Ambulatory Korean Population.

This study investigated 12-lead electrocardiogram (ECG) predictors associated with atrial fibrillation (AF) or flutter (AFL), specifically whether ventricular repolarization abnormalities in surface ECG (i.e., non-specific ST-T abnormalities [NSSTTA], QT prolongation, early repolarization [ER]) were associated with the development of AF or AFL.Methods and Results:This study included 16,793 ambulatory Koreans (mean age 48.2 years, 62.3% male) who underwent medical check-ups at Asan Medical Center in 2002 (NSSTTA, n=1,037 [6.2%]; ER, n=1,493 [8.9%]). The primary outcome was the incidence of ECG-documented AF or AFL. During follow-up, new-onset AF or AFL was documented in 334 subjects (2.0%). The incidence of AF or AFL at the 10-year follow-up was higher in patients with than without NSSTTA (3.5% vs. 1.6%; hazard ratio [HR] 1.79, 95% confidence interval [CI] 1.28-2.50). The QT interval was associated with a higher risk of AF or AFL (HR 1.12 [95% CI 1.07-1.17] per 10 ms), and the risk was even higher in patients with multiple-region NSSTTA (HR 2.30; 95% CI 1.64-3.21) and NSSTTA with QT prolongation (HR 4.06; 95% CI 2.14-7.69). ER was not associated with a higher risk of AF or AFL (HR 1.02; 95% CI 0.71-1.46). NSSTTA and QT prolongation, but not ER, were associated with a higher risk of future AF or AFL in a general ambulatory population after adjusting for parameters of atrial depolarization.

Evaluation of TP-E Interval and TP-E/QT Ratio in Panic Disorder.

Background and Objectives: The autonomic nervous system (ANS) is involved in panic disorders. ANS dysfunction has been shown to be associated with ventricular arrhythmia and increased heterogeneity of ventricular repolarization. However, there remains limited evidence of the relationship between panic disorders and ventricular depolarization markers, including the Tp-e interval and Tp-e/QT ratio. This study aimed to evaluate ventricular repolarization parameters in patients with panic disorder. Materials and Methods: In total, 40 patients with panic disorder, diagnosed using the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria, were included in the study group. The control group comprised of 50 age- and sex-matched healthy individuals. A standard 12 lead electrocardiogram was recorded on all participants, and heart rate, QT interval, QRS duration, Tp-e interval, and Tp-e/QT ratio were measured. Results: QRS durations and QT intervals were similar in the study and control groups. Compared to the control group, QTd, Tp-e, and cTp-e intervals as well as Tp-e/QT and Tp-e/QTc ratios were significantly increased in patients with panic disorder (p < 0.05 for all). In the study group, the Severity Measure for Panic Disorder—Adult score had a significant positive correlation with the Tp-e interval (r = 0.369, p < 0001), cTp-e interval (r = 0.531, p < 0.001), Tp-e/QT ratio (r = 0.358, p = 0.001), and Tp-e/QTc ratio (r = 0.351, p = 0.001). Conclusion: These findings indicate that panic disorders are associated with increased ventricular repolarization heterogeneity, which may be attributed to ANS dysregulation.

Melatonin Prevents 1A Phase Ventricular Fibrillation in Porcine Acute Myocardial Infarction Model

IntroductionVentricular fibrillation (VF) is a frequent complication of acute myocardial ischemia. Its prevention necessitates development of an antiarrhythmic cardioprotective strategy, and melatonin is considered to be a candidate antiarrhythmic agent. Though mechanisms of its action are largely unclear, generation of reactive oxygen species are thought to be its probable target. The objective of the present study was to find out an electrophysiological parameter subject to modification by melatonin and associated with VF incidence.MethodsAcute ischemia was induced in 25 anesthetized pigs by a 40‐min ligation of the left anterior descending coronary artery. After tightening the ligature, 12 animals were given melatonin (4 mg/kg, i.v.) and 13 placebo (control group). Intramyocardial unipolar electrograms were led from flexible electrodes (a total of 48 leads) positioned across ventricular walls and interventricular septum (IVS). Local activation times (AT, dV/dt min during QRS), end of repolarization times (RT, dV/dt max during T wave) and activation‐repolarization intervals (ARI, difference between RT and AT) were measured. After experiments, the hearts were excised, and parameters of oxidative stress were determined in the ischemic and nonischemic zones of ventricular myocardium.ResultsIn the control group, VFs were typically clustered during occlusion in 1A (1–5 min, 4 episodes) and 1B (17–40 min, 4 episodes) phases. Melatonin prevents development of 1A VFs (0 episodes, p=0.016) but did not modify occurence of 1B VFs (4 episodes). In the base of IVS (border ischemic zone), ATs in the period corresponding to 1A phase arrhythmias were shorter in the melatonin group as compared to the control group (Mean ± SD: 22±11 ms vs 39±18 ms, p=0.026, respectively) and were associated with VF incidence (OR 1.05 95% CI 1.01–1.10, p=0.023), while parameters of ventricular repolarization and oxidative stress did not differ between the treated and untreated animals.In conclusion, melatonin treatment improves conduction in the border ischemic zone and thereby prevents early ischemic VFs independently of oxidative stress development.Support or Funding InformationThe study was supported by Russian Science Foundation (RSF 18‐15‐00309).

Effect of anti-TNFα treatment on Tp-e interval and Tp-e/QT ratio in patients with ankylosing spondylitis: A case-control study

Aim: Ankylosing spondylitis (AS) is an axial spondyloarthropathy with multisystemic involvement. Anti-TNFα agents play a significant role in treatment options of this disease. In the literature, there is contradictory data about the effects of AS disease and anti-TNFα therapy on ventricular repolarization parameters. In this present study, we examined whether electrocardiographic parameters which reflect ventricular repolarization like QT, QTc, Tp-e, Tp-e/QT and Tp-e/QTc are different in AS patients than the control group and the effect of anti-TNFα agents on these parameters. Methods: Sixty patients diagnosed with AS (33 patients treated with anti-TNFα, 27 patients treated with non-anti-TNFα) and 60 healthy subjects were included in the study. Demographic, biochemical, electrocardiographic, and echocardiographic parameters of the study and control groups were compared. Tp-e interval was measured as the time interval between the T wave’s peak point and down slope tangent intersecting with the isoelectric line. Results: Heart rate, QT, QTc, and QRS were similar in both groups (P=0.232, P=0.660, P=0.220, and P=0.846, respectively); Tp-e (P=0.013), Tp-e/QT (P=0.006), and Tp-e/QTc (P=0.041) values were higher in the study group. Comparison analysis performed between groups treated with anti-TNFα and non-anti-TNFα showed no statistically significant difference in terms of heart rate, QT, QTc, QRS, Tp-e, Tpe/QT, and Tp-e/QTc values (P=0.916, P=0.655, P=0.335, P=0.999, P=0.731, P=0.848, and P=0.901, respectively). Conclusion: Although QT and QTc values were similar between AS patients and the control group, Tp-e, Tp-e/QT, and Tp-e/QTc values were higher in AS patients. Additionally, anti-TNFα treatment had a neutral effect on these parameters.

Akut Pankreatitli Hastalarda Tp-e Aralığı, Tp-e/QT Oranı and Tp-e/QTc Oranı’nın Değerlendirilmesi

Aim: Acute pancreatitis may affect cardiovascular system regardless of etiology. Electrocardiographic parameters such as QT interval, corrected QT interval (QTc), Tp-e interval and Tp-e/QT, Tp-e/QTc ratio can be used to evaluate myocardial repolarization. We aimed to investigate the effects of acute pancreatitis on the cardiovascular system and the relationship between ventricular repolarization parameters and the severity of the disease.Methods: Ventricular repolarization parameters (QT interval, QTc interval, Tp-e/QT, Tp-e/QTc ratio) of the patients who were included in the study and diagnosed with acute pancreatitis were compared with the control group patients. In addition, these parameters and Ranson, APACHE II and amylase values were taken into account in all patients in the pancreatitis group and the relationship between the severity of the disease and cardiac parameters was investigated.Results: 60 patients (30 acute pancreatitis and 30 control) were examined. Tp-e interval, Tp-e/QT and Tp-e/QTc ratios were significantly higher in the acute pancreatitis group compared to the control. In addition, Tp-e interval, Tp-e/QT and Tp-e/QTc ratios showed a positive correlation with the Ranson and APACHE II scores and Tp-e interval displayed a positive correlation with amylase levels.Conclusions: Tp-e interval, Tp-e/QT and Tp-e/QTc ratios can be used as a marker for the detection of ventricular arrhythmia risk in acute pancreatitis patients and Tp-e/QT and Tp-e/QTc ratios increased depending on the severity of AP and Tp-e interval increased in parallel with higher levels of amylase. Amylase level alone could be an indicator for increased risk of ventricular arrhythmia in patients with acute pancreatitis.