Inhomogeneity Of Repolarization Research Articles

Mechanisms of torsades de pointes: an update.

Torsades de Pointes (TdP) refers to a polymorphic ventricular tachycardia (VT) with undulating QRS axis that occurs in long QT syndrome (LQTS), although the term has been used to describe polymorphic ventricular tachyarrhythmias in which QT intervals are not prolonged, such as short-coupled variant of TdP currently known as short-coupled ventricular fibrillation (VF) and Brugada syndrome. Extensive works on LQTS-related TdP over more than 50 years since it was first recognized by Dessertennes who coined the French term meaning "twisting of the points", have led to current understanding of the electrophysiological mechanism that TdP is initiated by triggered activity due to early afterdepolarization (EAD) and maintained by reentry within a substrate of inhomogeneous repolarization. While a recently emerging notion that steep voltage gradients rather than EADs are crucial to generate premature ventricular contractions provides additions to the initiation mode, the research to elucidate the maintenance mechanism hasn't made much progress. The reentrant activity that produces the specific form of VT is not well characterized. We have conducted optical mapping in a rabbit model of electrical storm by electrical remodeling (QT prolongation) due to chronic complete atrioventricular block and demonstrated that a tissue-island with prolonged refractoriness due to enhanced late Na+ current (INa-L) contributes to the generation of drifting rotors in a unique manner, which may explain the ECG characteristic of TdP. Moreover, we have proposed that the neural Na+ channel NaV1.8-mediated INa-L may be a new player to form the substrate for TdP. Here we discuss TdP mechanisms by comparing the findings in electrical storm rabbits with recently published studies by others in simulation models and human and animal models of LQTS.

Abstract 11663: T Wave Alternans: A Clue in Plain Sight

Introduction: T-wave alternans (TWA) refers to the beat-to-beat variability in T-wave amplitudes or polarity on surface ECGs, and can signify susceptibility to malignant ventricular arrhythmias (VA). Aims: We present a case to emphasize the pathophysiology and clinical significance of this ECG finding. Case description: A 52 year-old female with history of HIV presents with shortness of breath and is treated for heart failure. In the ED, she has witnessed syncope and is found to have VT that progresses to VF. Resuscitation efforts are successful and include amiodarone loading. Figure 1A demonstrates baseline ECG on admission with a QTc of 495 ms. A few days later, an ECG reveals QTc of 696 ms with TWA (figure 1B). Shortly after, she develops polymorphic VT in the setting of long-short sequences and an R on T trigger (figure 1C) that is terminated with cardioversion. Review of pre-admission ECGs reveals that QTc prolongation occurred after initiation of a retroviral regimen that included rilpivirine and worsened with amiodarone. Both medications are discontinued, and she is eventually discharged with a QTc of 450 ms. Early theories for TWA's mechanism hypothesized that dispersion of refractoriness resulted in depolarization through alternating pathways and thus this phenomenon. Recent understanding further suggests that TWA occurs as a result of cellular alternans and variation in action potential duration due to dysregulation of repolarization. If discordant repolarization alternans ensues, whereby neighboring cells repolarize in opposite phases (long-short, short-long), the resultant repolarization gradient and heterogeneity in cellular repolarization serves as the substrate for VA; if a premature beat encounters refractory myocardium and unidirectional block occurs, a re-entrant excitation tachycardia can be initiated. Conclusions: TWA on ECG suggests myocardial electrical instability as a result of cellular repolarization inhomogeneity.

The Diagnostic Value of QT Dispersion for Acute Coronary Syndrome in Patients with Nondiagnostic Initial Electrocardiograms

Introduction: Chest pain is a frequent cause for admission to the emergency department (ED). It can be a sign of various conditions, from a minor disorder to a life-threatening disease such as acute myocardial infarction (AMI). Despite the availability of modern-day tools for the diagnosis of AMI, about 5% of patients with AMI are missed in the ED, with subsequent associated morbidity and mortality. QT dispersion as a marker for arrhythmic potential being a marker of in-homogeneity of ventricular repolarization. The QT dispersion is increased in myocardial ischemia. Aims: This study we hypothesized that QTD could accurately identify patients with the acute coronary syndrome (ACS) who presented with chest pain and nondiagnostic initial electrocardiograms (ECGs). Subjects and Methods: The study population included (50) patients (37 males, 13 females) and (10) chronic stable ischemic patients as a control group, they were all in sinus rhythm on admission. All the studied patients were subjected to: History taking; complete physical examination was performed to rule out any other medical problems, standard 12-lead ECG, cardiac markers, echocardiographic examination. QT interval was calculated. The difference between the maximum and minimum QT intervals, occurring in any of the 12 leads, was measured as QTD. A corrected QT interval (QTc) of >440 ms is defined as abnormal, and the difference between QTc max and QTc min was calculated as QTcD. QT dispersion ≤40 ms was considered normal. Results: In the present study, we found that 26 patients (52%) have prolonged QTD (mean 78.800 ms, standard deviation [SD] ±49.555) and 44 patients (88%) have prolonged cQTD (mean 83.322 ms, SD ± 48.491) For patients who were admitted to the ED with chest pain and nondiagnostic initial ECG but later diagnosed as having ACS. Furthermore, we found that only 6 (12%) of patients have a significant prolongation QTD than normal in initial nondiagnostic ECG with elevated cardiac biomarkers (creatine kinase myocardial band at 0 h 48, mean creatine kinase myocardial band (CK MP) at 12 h was 145.833 ± SD 52.660, creatine phosphokinase (CPK) at 0 h: 635.33, mean CPK at 12 h 2448.66 ± SD 538.744). It has been suggested that the initial QTD level has a low predictive power for new cardiac events but that QTD can be more helpful for low-risk patients. Conclusion: Hence, in this study, we found that QTD and QTcD values are higher for ACS patients than for patients without ACS with nondiagnostic initial ECG.

Comparison of QT dispersion in patients with ST elevation acute myocardial infarction (STEMI) before and after treatment by streptokinase versus primary percutaneous coronary intervention (PCI)

BackgroundQT dispersion (QTD) represents inhomogeneous ventricular repolarization such that an increased QTD may predispose the heart to malignant ventricular arrhythmias (VAs). This study was conducted to compare QTD in patients with ST-elevation myocardial infarction (STEMI) before and after treatment by streptokinase (SK) versus primary percutaneous coronary intervention (PCI).MethodsThe present case–control study was conducted on 185 STEMI patients who received SK (115 cases) or underwent primary PCI (70 cases). QTD and QT corrected dispersion before and 24 h after treatment. Likewise, they were also found to correct fatal arrhythmias (VT and VF) during the first 24 h after admission, and ejection fraction (EF) 24 h after treatment was evaluated.ResultsQTD decreased in the primary PCI group, though no significant difference was seen between the two studied groups (P > 0.05). A significant increase was detected in the EF mean values for the primary PCI-treated patients (P = 0.022). Moreover, there was a significant reduction in QTD of patients with fatal arrhythmias in the primary PCI group (P = 0.022).ConclusionAn overall QTD reduction in the primary PCI group and a significant decrease in QTD of patients with fatal arrhythmias in the primary PCI group show that this treatment strategy is more efficient than thrombolytic therapy. As an important indicator of proper myocardial function, EF can independently predict improved myocardial function in the primary PCI group.

Spotlights on some electrocardiographic paradigms: How should we evaluate normal reference values of Tp–Te interval, Tp–Te dispersion and Tp–Te/QT ratio?

Experimental and clinical studies evaluating the Tp-Te interval and Tp-Te/QT ratio have reported conflicting data. The overlap between normal Tp-Te/QT ratios (0.17 ±0.02-0.27 ±0.06 ms) and pathological values (0.20 ±0.03-0.30 ±0.06 ms) measured in earlier studies has raised questions about this ECG measurement technique. To analyze normal values of the Tp-Te interval, Tp-Te dispersion Tp-Te(d) and the Tp-Te/QT ratio based on electrocardiographic (ECG) assessment across sex and age groups in a healthy Turkish population. A total of 1,485 healthy participants (723 men) were enrolled into the study. The age of the participants ranged 17-75 years and they did not have either any cardiovascular/systemic disorders or risk factors for atherosclerosis which were detected with physical examination and laboratory tests. The Tp-Te interval, Tp-Te(d) and Tp-Te/QT ratio were determined from V1-V6 derivations. For the entire study, the median Tp-Te interval was 66.0 (64.0-70.0) ms, the Tp-Te(d) was 15.0 (10.0-20.0) ms, and the Tp-Te/QT ratio was 0.18 (0.17-0.19). The Pearson's correlation test demonstrated that the Tp-Te/QT ratio significantly correlated with older age (r = 0.297; p < 0.0001), left ventricular (LV) end-diastolic diameter (LVEDD; r = 0.481; p < 0.0001), body mass index (BMI; r = 0.421; p < 0.0001), body surface area (BSA; r = 0.191; p < 0.0001), LV end-diastolic volume (LVEDV; r = 0.484; p < 0.0001), LVEDV index (r = 0.450; p < 0.0001), LV mass (r = 0.548; p < 0.0001), and LV mass index (r = 0.539; p < 0.0001). The reference values for Tp-Te interval, Tp-Te(d) and Tp-Te/QT ratio are associated with age, BMI, BSA, LVEDV, LVEDV index, LV mass, and LV mass index. These structural elements should be considered when using these ECG parameters for assessing repolarization inhomogeneity. These findings may guide further studies assessing healthy and diseased populations.

Body Surface Mapping of Ventricular Repolarization Heterogeneity: An Ex-vivo Multiparameter Study.

BackgroundIncreased heterogeneity of ventricular repolarization is associated with life-threatening arrhythmia and sudden cardiac death (SCD). T-wave analysis through body surface potential mapping (BSPM) is a promising tool for risk stratification, but the clinical effectiveness of current electrocardiographic indices is still unclear, with limited experimental validation. This study aims to investigate performance of non-invasive state-of-the-art and novel T-wave markers for repolarization dispersion in an ex vivo model.MethodsLangendorff-perfused pig hearts (N = 7) were suspended in a human-shaped 256-electrode torso tank. Tank potentials were recorded during sinus rhythm before and after introducing repolarization inhomogeneities through local perfusion with dofetilide and/or pinacidil. Drug-induced repolarization gradients were investigated from BSPMs at different experiment phases. Dispersion of electrical recovery was quantified by duration parameters, i.e., the time interval between the peak and the offset of T-wave (TPEAK-TEND) and QT interval, and variability over time and electrodes was also assessed. The degree of T-wave symmetry to the peak was quantified by the ratio between the terminal and initial portions of T-wave area (Asy). Morphological variability between left and right BSPM electrodes was measured by dynamic time warping (DTW). Finally, T-wave organization was assessed by the complexity of repolarization index (CR), i.e., the amount of energy non-preserved by the dominant eigenvector computed by principal component analysis (PCA), and the error between each multilead T-wave and its 3D PCA approximation (NMSE). Body surface indices were compared with global measures of epicardial dispersion of repolarization, and with local gradients between adjacent ventricular sites.ResultsAfter drug intervention, both regional and global repolarization heterogeneity were significantly enhanced. On the body surface, TPEAK-TEND was significantly prolonged and less stable in time in all experiments, while QT interval showed higher variability across the interventions in terms of duration and spatial dispersion. The rising slope of the repolarization profile was steeper, and T-waves were more asymmetric than at baseline. Interventricular shape dissimilarity was enhanced by repolarization gradients according to DTW. Organized T-wave patterns were associated with abnormal repolarization, and they were properly described by the first principal components.ConclusionRepolarization heterogeneity significantly affects T-wave properties, and can be non-invasively captured by BSPM-based metrics.

Does obesity have an effect on the ECG in children?

This review summarizes current data on influences of childhood obesity on the 12-lead electrocardiogram (ECG). Studies on obese adults showed a higher risk of cardiovascular complications and also, partly pathological, ECG alterations. Data on ECG alterations in obese children is rare. In current studies, no pathological findings were found. All alterations, which mimic the later pathological phenomena in obese adults, were within normal ranges. Studies reported significantly longer P-wave time and P-wave dispersion (Pd) in obese children [Üner A, Doğan M, Epcacan Z, Epçaçan S. The effect of childhood obesity on cardiac functions. J Pediatr Endocr Met 2014;27:261-71.], no correlation of heart rate, P-wave, or QT dispersions (QTd) [Akyüz A, Alpsoy S, Akkoyun DC, Nalbantoǧlu B, Tülübaș F, et al. Effect of overweight on P-wave and QT dispersions in childhood. Turk Kardiyol Dern Ars 2013;41:515-21.], significantly higher QTd in obese children [Yildirim S, Binnetoglu FK, Battal F, Aylanc H, Nazan Kaymaz N, et al. Relation between QT variables and left ventricular geometry in athletes and obese children. Acta Med Port 2016;29:95-100.], no significant association between obesity and QTc interval (QTc), but longer PR intervals, wider QRS duration and left axis shifting of frontal P-wave, QRS and T-wave axes [Sun G, Li Y, Zho X, Guuo X, Zhang X, et al. Association between obesity and ECG variables in children and adolescents: a cross-sectional study. Exp Ther Med 2013;6:1455-62.], significant prolongation of QTc, T peak-to-end, and QTd in the obese children [Paech C, Liebold A, Gebauer RA, Wagner F, Vogel M, et al. Relative QT interval prolongation and electrical inhomogeneity of cardiac repolarization in childhood obesity. Prog Pediatr Cardiol 2017;47:64-7.], slight shift to the left in the QRS axis (with no changes in the P axis), increased amplitudes of the left-sided leads in obese children, and no correlation of the heart rate with the weight [Paech C, Anhalt M, Gebauer RA, Wagner F, Vogel M, et al. New normal limits for pediatric ECG in childhood obesity? Influence of childhood obesity on the ECG. Prog Pediatr Cardiol 2018;48:119-23.]. Altogether, the study results are inconsistent. Clearly, pathological phenomena in the ECG of obese children were not reported: only preliminary stages like QTc prolongation within the norm were found. The pathological alterations seen in adult obese patients are not (yet) seen in childhood. The slight changes reported in childhood obesity are likely to manifest later and to develop into pathological phenomena in obese adults and, therefore, might increase the risk of cardiovascular events like arrhythmia and sudden cardiac death in adulthood.

Endothelin receptors in the brain modulate autonomic responses and arrhythmogenesis during acute myocardial infarction in rats

AimsEndothelin has been implicated in various processes in the brain, including the modulation of sympathetic responses. The present study examined the pathophysiologic role of brain endothelin-receptors in the setting of acute myocardial infarction, characterized by high incidence of ventricular tachyarrhythmias. Main methodsWe investigated the effects of intracerebroventricular administration of antagonists of endothelin-receptors ETA, ETB, or both, during a 24 h-observation period post-coronary ligation in (n = 70) rats. Continuous recording was performed via implanted telemetry transmitters, followed by arrhythmia-analysis and calculation of autonomic indices derived from heart rate variability. The regional myocardial electrophysiologic properties were assessed by monophasic action potentials and multi-electrode recordings. Key findingsSympathetic-activity was decreased and vagal-activity was enhanced after intracerebroventricular ETA-receptor blockade, thus attenuating regional myocardial repolarization inhomogeneity. As a result, the incidence of ventricular tachyarrhythmias was markedly lower in this group. Such effects were also observed after intracerebroventricular blockade of ETB-, or both, ETA- and ETB-receptors, although to a lesser extent. SignificanceETA-receptors in the brain modulate sympathetic and vagal responses and alter arrhythmogenesis during evolving myocardial necrosis in rats. These findings provide insights into arrhythmogenic mechanisms during acute myocardial infarction and call for further investigation on the role of endothelin in the central autonomic network.

P1504Impact of myocardial ischemia induced by exercise stress echocardiography on the QT dispersion in patients with the left bundle branch block

Abstract Background/Introduction ECG has always provided very useful information that can be used to diagnosis, treatment and prevention of cardiovascular events, but ECG changes is not useful to the detection of myocardial ischemia in patients with left bundle branch block (LBBB). QT dispersion (QTd) is a measure of inhomogeneous repolarization of myocardium. Abnormally high QTd has been correlated with risk of cardiac death in coronary patients. Purpose The aim of this study was to establish the impact of myocardial ischemia induced by exercise stress echocardiography on the QT dispersion in patients with the left bundle branch block. Methods The study involved 123 patients with LBBB, average age 52.7 years. In all subjects clinical examination, standard ECG and exercise stress echocardiography, were performed. The criterion for myocardial ischemia was the appearance of transient segmental wall motion abnormality. The first ECG was done before the exercise stress echocardiography and the second one was done immediately after exercise, with calculation of corrected QT dispersion (QTdc). Results During exercise stress echocardiography, in 45 (36.6%) subjects wall motion abnormality occurred (group with myocardial ischemia: MI), and 78 (63.4%) subjects were without ischemia (group without myocardial ischemia: NMI). Before starting the exercise stress echocardiography, MI group patients had significantly higher values of QTdc (61.2±17.6 vs 43.6±15.4 ms; p&lt;0.001) in comparison to NMI group patients. During the exercise stress echocardiography, the QTdc significantly increased in MI group from 61.2±17.6 to 87.4±20.3 ms (p&lt;0.001). In the NMI group there were no significant changes in the values QTdc during exercise stress echocardiography (from 43.6±15.4 to 46.5±19.8 ms (p - NS). Conclusions Significant increase of QT dispersion is associated with the occurrence of myocardial ischemia during exercise stress echocardiography in patients with LBBB. This new diagnostic approach, of using QT dispersion, significantly improves the clinical usefulness of exercise stress echocardiography in detecting myocardial ischemia in patients with LBBB.

Evaluation of the QTc internal and QT dispersion in patients with newly detected clinical hypothyroidism

Background: Thyroid hormones play an important role in the orchestration of various metabolic functions in the body and thus thyroid dysfunction can produce dramatic cardiovascular effects. Electrocardiographic changes such as bradycardia, low voltage complexes, and varying degrees of heart block are commonly recognized in hypothyroid patients. Hypothyroidism has been found to be associated with increased cardiovascular morbidity and mortality. Hence, it is important to investigate the ECG profile in these patients. The present study was aimed at evaluating the QTc interval and QT dispersion, an indicator of inhomogeneity of ventricular repolarisation and cardiac autonomic modulation in patients with newly detected clinical hypothyroidism.Methods: 50 patients with newly detected clinical hypothyroidism and 50 healthy controls were included in the study. The ECG was recorded and the heart-rate, QTc interval and QT dispersion were calculated.Results: The mean heart-rate was found to be significantly (p &lt;0.05) reduced in hypothyroid patients when compared to healthy controls. The mean QTc interval and QT dispersion were significantly increased in hypothyroid patients when compared to controls. QTmin and QTmax of cases and controls also showed a statistically significant difference.Conclusion: Thus, the present study confirms the role of thyroid hormones on the cardiovascular system, particularly on ventricular repolarisation and cardiac autonomic modulation. Hence, early and prompt therapy with levothyroxine may help to prevent the adverse events resulting from cardiovascular dysfunction.

Prevalence and significance of notched T-waves in elite professional cyclists

ObjectivesTo identify the frequency and significance of notched T-waves (NTW) in elite endurance athletes. MethodsProfessional cyclists were followed for 4 years with a clinical, electrocardiographic and echocardiographic assessment. Electrocardiograms were classified according to the presence or absence of NTWs; clinical and echocardiographic correlates were assessed. Results42 Caucasian male cyclists were included. NTW were detected in 8 (19%) cyclists who showed significantly longer QT (461 ± 15 vs 422 ± 33 ms, p < 0.01) and QTc intervals (434 ± 19 vs 383 ± 21 ms, p < 0.01), a larger left ventricular end-diastolic volume (163 ± 27 vs 137 ± 23 mL, p = 0.014), end-diastolic volume index (84 ± 13 vs 73 ± 11 mL, p = 0.037) and end-diastolic apex-to-base length (9.9 ± 0.7 vs 9.3 ± 0.5 mm. p = 0.035). There were no detected arrhythmic events, and echocardiography did not reveal any abnormalities. ConclusionsThis is to our knowledge the first study reporting a high prevalence of NTW in athletes. In our small cohort of cyclists NTW were associated with QT interval prolongation and left ventricular changes. This may be indicative of underlying inhomogeneity of repolarisation. Expanding on this research could reveal a role for NTW in identifying ventricular morphological changes.

Complex electrophysiological remodeling in postinfarction ischemic heart failure

Heart failure (HF) following myocardial infarction (MI) is associated with high incidence of cardiac arrhythmias. Development of therapeutic strategy requires detailed understanding of electrophysiological remodeling. However, changes of ionic currents in ischemic HF remain incompletely understood, especially in translational large-animal models. Here, we systematically measure the major ionic currents in ventricular myocytes from the infarct border and remote zones in a porcine model of post-MI HF. We recorded eight ionic currents during the cell's action potential (AP) under physiologically relevant conditions using selfAP-clamp sequential dissection. Compared with healthy controls, HF-remote zone myocytes exhibited increased late Na+ current, Ca2+-activated K+ current, Ca2+-activated Cl- current, decreased rapid delayed rectifier K+ current, and altered Na+/Ca2+ exchange current profile. In HF-border zone myocytes, the above changes also occurred but with additional decrease of L-type Ca2+ current, decrease of inward rectifier K+ current, and Ca2+ release-dependent delayed after-depolarizations. Our data reveal that the changes in any individual current are relatively small, but the integrated impacts shift the balance between the inward and outward currents to shorten AP in the border zone but prolong AP in the remote zone. This differential remodeling in post-MI HF increases the inhomogeneity of AP repolarization, which may enhance the arrhythmogenic substrate. Our comprehensive findings provide a mechanistic framework for understanding why single-channel blockers may fail to suppress arrhythmias, and highlight the need to consider the rich tableau and integration of many ionic currents in designing therapeutic strategies for treating arrhythmias in HF.

Relation of homeostasis model of insulin resistance and body mass index with cardiac repolarization inhomogeneity in overweight and obese patients

In obese individuals, asymptomatic minimal myocardial dysfunction can be encountered even in the absence of structural of functional cardiac alterations. Novel electrocardiographic (ECG) parameters are used to predict arrhythmias related to this situation. We aimed to evaluate body mass index (BMI) and homeostasis model of insulin resistance (HOMA-IR) levels and investigate their relationship with the novel ECG parameters. The study was conducted with 250 individuals in five groups (normoweight, overweight, class I obese, class II obese, and class III obese) each including 50 subjects. The ECGs of the individuals were retrospectively reviewed. Corrected QT (QTc), QTc dispersion (QTcd), Tpeak-Tend (Tp-e) interval, Tp-e dispersion (Tp-ed), and Tp-e/QT and Tp-e/QTc ratios were calculated and their relationship with BMI and HOMA-IR was investigated. ECG parameters indicating ventricular repolarization inhomogeneity were significantly different in overweight individuals compared with the normoweight individuals. Comparing overweight and obese subjects, it was determined that QTc, QTcd and Tp-ed parameters were significantly associated with obesity and showed positive correlations with BMI and HOMA-IR. There was a positive relationship of BMI and HOMA-IR with the novel parameters indicating ventricular repolarization abnormality. Novel and simple ECG parameters including QTc, QTcd, and Tp-ed might be beneficial in monitoring of such patients for critical cardiac events, such as ventricular tachycardia or sudden cardiac death.

Relative QT interval prolongation and electrical inhomogeneity of cardiac repolarization in childhood obesity

ObjectiveStudies in adults demonstrated an association of obesity with prolongation of cardiac repolarization and an increased risk of ventricular arrhythmia and sudden cardiac death. The aim of this study was to evaluate potential alterations in cardiac repolarization in obese children. Methods83 lean and 132 obese consecutive healthy pediatric volunteers from the LIFE Child Study cohort were prospectively enrolled and their ECGs were analyzed. ResultsThere was a significant prolongation of corrected QT interval (p=0.001), T peak-to-end (p=0.001) and QT dispersion (p=0.001) in obese compared to lean children. The QT interval prolongation was more pronounced in girls than in boys (p=0.002), whereas there were no significant sex dependent differences in QT dispersion (p=0.18) or T peak-to-end (p=0.39). ConclusionChildhood obesity seems to be associated with a cardiac electrical inhomogeneity with the hypothetical potential for an increased arrhythmogenic risk. Furthermore, it causes a relative prolongation of the QTc interval compared to lean children with a more evident effect in females, yet without prolongation beyond the upper limits of normal.

Usefulness of QT dispersion in clinical practice

The measurement of QT dispersion in the surface electrocardiogram has been proposed as a non invasive method for assessing inhomogeneity of myocardial repolarization and has been linked to an increased risk of arrhythmic cardiac death. Several studies have evaluated the use of QTd in a wide variety of cardiac diseases and have reached conflicting conclusions regarding its clinical significance.

Evaluation of inhomogeneities of repolarization in patients with psoriasis vulgaris.

IntroductionThe arrhythmia potential has not been investigated adequately in psoriatic patients. In this study, we assessed the ventricular repolarization dispersion, using the Tp-e interval and the Tp-e/QT ratio, and investigated the association with inflammation.Material and methodsSeventy-one psoriasis vulgaris patients and 70 age- and gender-matched healthy individuals were enrolled in the study. The severity of the disease was calculated using Psoriasis Area and Severity Index scoring. The QTd was defined as the difference between the maximum and minimum QT intervals. The Tp-e interval was defined as the interval from the peak of the T wave to the end of the T wave. The Tp-e interval was corrected for heart rate. The Tp-e/QT ratio was calculated using these measurements.ResultsThere were no significant differences between the groups with respect to basal clinical and laboratory characteristics (p > 0.05). The Tp-e interval, the corrected Tp-e interval (cTp-e) and the Tp-e/QT ratio were also significantly higher in psoriasis patients compared to the control group (78.5 ±8.0 ms vs. 71.4 ±7.6 ms, p < 0.001, 86.3 ±13.2 ms vs. 77.6 ±9.0 ms, p < 0.001 and 0.21 ±0.02 vs. 0.19 ±0.02, p < 0.001 respectively). A significant correlation was detected between the cTp-e time and the Tp-e/QT ratio and the PASI score in the group of psoriatic patients (r = 0.51, p < 0.001; r = 0.59, p < 0.001, respectively).ConclusionsIn our study, we detected a significant increase in the Tp-e interval and the Tp-e/QT ratio in patients with psoriasis vulgaris. The Tp-e interval and the Tp-e/QT ratio may be predictors for ventricular arrhythmias in patients with psoriasis vulgaris.

Transmural dispersion of repolarization: a complementary index for cardiac inhomogeneity.

We thank Dr Dogan and his team for his thoughtful comments and suggestions. The first comment to our study relates to the percentage of defective cQTD patients that was higher in our study as compared to previous studies.[1]–[3] We would like to point out that defective cQTD occurred in 40% while recovery of cQTD occurred in the majority of patients (60%). Also, the mean cQTD in the overall population significantly decreased after transcatheter aortic valve implantation (TAVI) (47 to 40 ms, P = 0.049). We do agree, however, that cQTD determination to assess ventricular inhomogeneity and arrhythmia risk suffers from (technical) measurement difficulties resulting in increased inter- and intra-observer variabilities and imperfect estimates of the true ventricular repolarization inhomogeneity. Therefore, a different methodological perspective such as measurement of T-peak to T-end wave dispersion should also be investigated in patients undergoing TAVI albeit that this method is also likely to suffer from measurement difficulties when assessing the end of the T wave (especially in lead V1, V2 or aVF). We agree that further research is indeed needed to investigate whether repolarization dispersion measurements correlate with sudden death and arrhythmia risk as suggested by Dogan et al. with methods that include or correct for the different electrical properties of the different myocardial cells.

OP-028 Changing the Repolarization Processes of the Ventricles in Patients with Arterial Hypertension

In recent years, much attention is paid to the study of dispersions of (QTd) QT interval values in patients with arterial hypertension (AH) - the marker of repolarization inhomogeneity and the predictor of ventricular arrhythmias (VA).

CRT-115 Qt Dispersion Correlation to St Segment Resolution In STEMI Patients

QT dispersion (Qtd) is defined as the difference between the maximal and the minimal values of the QT through the peripheral and precordial leads. It is considered as an arrhythmogenic indice and reflects the inhomogeneity of repolarization. To investigate the effect of revascularization on

Chronic Hyperglycemia and Inhomogenous Ventricular Repolarisation - an Electrophysiological Approach

The QT interval expresses the myocardial depolarization and repolarisation time. QTd is regarded as an index of myocardial electrical activity. Present study was done to investigate the differences in QTd between non-diabetics, well controlled diabetes patients and poorly controlled diabetics. The study group comprised of 60 type 2 diabetes patients within the age group of 40–60 years coming to diabetic clinic and those hospitalized in medicine wards, They were further classified in to two sub-groups(n = 30 in each group), Type2 diabetes patients with good glycemic control (HbA1c 7). Glycosylated hemoglobin level was detected by calorimetric method (spectronic -2). The control group consisted of 30 age matched healthy subjects (volunteers). After thorough examination of the subjects as per the proforma, 12 lead ECG was taken with (Montara instrument ELI 250), QT interval was measured on the 12 lead resting ECG. QTd was calculated manually. The value of QT dispersion was significantly high (p < 0.01) in Type2 Diabetes mellitus patients with poor glycemic control compared to well controlled diabetics and healthy subjects. Chronic hyperglycemia is associated with high QT dispersion which suggests that such patients have a greater inhomogeneity of repolarization and therefore they are more prone for adverse cardiovascular events.