The prognostic value of the Tpeak-Tend interval in patients undergoing primary percutaneous coronary intervention for ST-segment elevation myocardial infarction

Retracted: T-peak to T-end Interval Predicts Appropriate Shocks in Patients with Heart Failure Undergoing Implantable Cardioverter Defibrillator Implantation for Primary Prophylaxis

BACKGROUND

T-wave peak to T-wave end interval (Tp-e) correlates with dispersion of ventricular repolarization. The purpose of this study was to assess the ability of Tp-e to predict appropriate implantable cardioverter defibrillator (ICD) shocks and all-cause mortality in patients who underwent ICD implantation for primary prophylaxis.

METHODS

Two hundred twenty-eight patients with left ventricular ejection fraction ≤35% and an ICD implanted were followed-up prospectively. Patients divided into two subgroups according to presence of appropriate ICD shocks (Group 1: 112 patients with ICD shocks, Group 2: 116 patients without shocks). End points were appropriate ICD therapy due to ventricular tachycardia (VT)/ventricular fibrillation (VF), death, and a combined end point of VT/VF or death.

RESULTS

During a mean follow-up of 22.3 ± 7.7 months, appropriate ICD shocks were observed in 112 of 228 patients (49.1%). The mean duration of the Tp-e Group 1 was significantly longer than Group 2 (115.3 ± 22.2 vs 104.7 ± 20.2 ms, P < 0.001). Ischemic etiology and Tp-e duration were found to be independent predictors of ICD therapy. When the patients were divided into two groups based on Tp-e interval, there was no significant difference regarding the mortality between groups (21.2% vs 21.8%, P: 0.186). However, appropriate ICD shocks due to VT/VF (37.5% vs 58.8%, P < 0.001) and combined end point (39.4% vs 64.5%, P: 0.002) were significantly higher in patients with longer Tp-e group.

CONCLUSIONS

Tp-e interval independently predicts appropriate ICD shocks in patients with systolic dysfunction and ICDs implanted for primary prevention.

The value of the 12-lead electrocardiogram in the prediction of sudden cardiac death

Sudden cardiac death (SCD) can be caused by several clinical conditions, overt or misconceived, which recognize different pathophysiologies determining the development of fatal arrhythmic events. In the various forms of structural heart disease such as ischaemic heart disease, cardiomyopathies (e.g. hypertrophic cardiomyopathy, dilated cardiomyopathy, and arrhythmogenic cardiomyopathy), channelopathies (e.g. long-QT syndrome, congenital short QT, Brugada syndrome, early repolarization (ER) syndrome, and idiopathic ventricular fibrillation) but also in the apparently healthy subject, the 12-lead electrocardiogram (ECG) has proved, over the years, to be a reliable and readily available method for stratifying the risk of adverse arrhythmic events and consequently SCD. Several electrocardiographic markers have been shown to be associated with adverse outcomes in different types of patients. Although with different sensitivity and specificity in each clinical condition, depolarization abnormalities, such as QRS fragmentation, Q waves, QRS duration, left posterior fascicular block, low QRS voltage, and left ventricular hypertrophy and similarly repolarization abnormalities as ER pattern, T wave alternans, QT interval, and QT dispersion, have shown significant efficacy in predicting SCD. Despite the advancement of techniques especially in the field of imaging, the correct interpretation of the 12-lead ECG remains, therefore, an effective tool for assessing the possible prognostic outcome in terms of arrhythmic risk and SCD in different types of patients.

A Longer Tpeak-Tend Interval Is Associated with a Higher Risk of Death: A Meta-Analysis

A noninvasive tool for cardiovascular risk stratification has not yet been established in the clinical routine analysis. Previous studies suggest a prolonged Tpeak-Tend interval (the interval from the peak to the end of the T-wave) to be predictive of death. This meta-analysis was designed to systematically evaluate the association of the Tpeak-Tend interval with mortality outcomes. Medline (via PubMed), Embase and the Cochrane Library were searched from 1 January 2008 to 21 July 2020 for articles reporting the ascertainment of the Tpeak-Tend interval and observation of all-cause-mortality. The search yielded 1920 citations, of which 133 full-texts were retrieved and 29 observational studies involving 23,114 patients met the final criteria. All-cause deaths had longer Tpeak-Tend intervals compared to survivors by a standardized mean difference of 0.41 (95% CI 0.23-0.58) and patients with a long Tpeak-Tend interval had a higher risk of all-cause death compared to patients with a short Tpeak-Tend interval by an overall odds ratio of 2.33 (95% CI 1.57-3.45). Heart rate correction, electrocardiographic (ECG) measurement methods and the selection of ECG leads were major sources of heterogeneity. Subgroup analyses revealed that heart rate correction did not affect the association of the Tpeak-Tend interval with mortality outcomes, whereas this finding was not evident in all measurement methods. The Tpeak-Tend interval was found to be significantly associated with all-cause mortality. Further studies are warranted to confirm the prognostic value of the Tpeak-Tend interval.

The relationship between length of stay in intensive care unit and Tpeak-Tend and Tpeak-Tend/QTc ratio in COVID 19 patients with acute coronary syndrome

Background

Patients with coronavirus disease 2019 (COVID-19) can develop cardiac injury resulting in cardiac arrhythmias, myocarditis, and acute coronary syndrome (ACS). In this study, we aimed to investigate whether COVID-19 infection affects ventricular repolarization parameters such as Tpeak-Tend interval (Tp-e), QT interval, corrected QT (QTc), Tp-e/QT, and Tp-e/cQT in patients with ACS.

Methods

The study consisted of two groups. The first group included patients with ACS and COVID-19 (Group 1) (n = 50). Polymerase chain reaction test positive patients were enrolled. The second group included patients with only ACS (Group 2) (n = 100). The risk of ventricular arrhythmias was evaluated on the basis of the measured electrocardiographic Tp-e and QT interval, and QTc, Tp-e/QT, and Tp-e/QTc values.

Results

Tp-e interval, QTc, and Tp-e/QTc were significantly higher in the group1 than group 2 (p < .001, p < .018, and p < .001, respectively). Significant positive correlations were found between Tp-e, D-dimer level, and C-reactive protein (CRP) level in the group1 (p = .002, p = 0 .03, and p = .021, respectively). Univariate and multivariate regression analyses revealed that Tp-e was one of the independent predictor of length of stay in the intensive care unit (ICU). (B = 1.662, p = .006 and B = 1.804, p = .021, respectively).

Conclusions

In the patients with ACS, COVID-19 infection caused increases in QTc, Tp-e, and Tp-e/QTc ratio. In addition, age and prolonged Tp-e were found to be independent predictors of prolonged ICU stay.

Tpeak-Tend Interval during Pregnancy and Postpartum

BACKGROUND

Pregnancy is a condition in which new cardiac arrhythmias can occur or prior undiagnosed arrhythmias may provide symptoms. The occurrence of severe ventricular arrhythmias and polymorphic ventricular tachycardia that may lead to fainting or sudden cardiac death is promoted by the prolongation of the QTc interval. The post-partum adaptation period is the most arrhythmogenic. TpTe (Tpeak-Tend interval) is a novel marker of arrhythmogenesis by many considered a more sensitive marker than QTc.

OBJECTIVE

The aim of our work was to determine the TpTe interval (Tpeak-Tend) in women in the first, second and third trimester of pregnancy and the post-partum period.

MATERIALS AND METHODS

The study group consisted of 128 women in pregnancy or postpartum and a control group of 32 non-pregnant women. A standard 12-lead ECG (electrocardiograph) recording with evaluation of the duration of TpTe and QTc was performed in all patients.

RESULTS

In comparison to the non-pregnant women, higher values of QTc and TpTe were observed starting in the first trimester with highest values observed in the postpartum period. Mean duration of TpTe interval during pregnancy (81.59 ± 5.92 ms) and in the whole study group (pregnancy + postpartum) (85.46 ± 6.45 ms) was significantly longer (p < 0.001) compared to the TpTe interval in the control group (74.06 ± 6.14 ms). During pregnancy and postpartum, the increase in the TpTe interval in comparison to the increase in the QTc parameter (31.10% vs. 4.18%) was significantly higher (p < 0.001).

CONCLUSIONS

The study showed an increase in the duration of the TpTe interval and QTc parameter during pregnancy and postpartum with the highest values in the postpartum period. TpTe interval increase was significantly higher compared to QTc increase during pregnancy and postpartum. Changes of TpTe interval were not associated with any clinical outcome or measure of arrythmia burden. Further studies are needed in order to see the clinical significance of these ECG findings, in particular for larger groups of patients with automatic measurement in correlation with echocardiography.

Prognostic value of infarct-related-lead Tpeak-Tend/QT ratio in patients with ST-segment elevation myocardial infarction

Tpeak-Tend/QT ratio (Tp-e/QT) in patients with ST-segment elevation myocardial infarction (STEMI) is reportedly associated with major adverse cardiac events (MACEs). However, Tp-e/QT measurement methods are controversial, and few studies have clarified the effect of different Tp-e/QT measures on prognosis. Our study is the first to investigate the advantages of the Tp-e/QT measured by infarct-related-lead method in predicting MACEs during hospitalization and long-term mortality in patients with STEMI. A total of 427 STEMI patients undergoing primary percutaneous coronary intervention (PCI) were included in this study. The Tp-e/QT before PCI was measured by traditional 12-lead method and infarct-related-lead method. Outcomes were tested using comparative statistics, logistic regression, receiver operating characteristic (ROC) curve and Kaplan-Meier survival analysis. There were 62 (14.5%) patients who had MACEs in-hospital. Logistic regression showed that the Tp-e/QT in infarct-related-lead was an independent predictor (p < 0.001). The area under the ROC curve (AUC) of the Tp-e/QT in infarct-related-lead was larger than that in the Tp-e/QT in traditional 12-lead (0.889 vs 0.741), and the optimal cutoff value was 0.32. The three-year survival rate of patients in the infarct-related-lead Tp-e/QT < 0.32 group was better than Tp-e/QT ≥ 0.32 group in Kaplan-Meier survival analysis (93.9 vs 87.0%). When stratified according to infarct-related arteries, the results showed that the common odds ratio of patients in Tp-e/QT ≥ 0.32 group occurred MACEs was 1.562, P = 0.038. The infarct-related-lead Tp-e/QT performed better than the traditional 12-lead Tp-e/QT in predicting poor prognosis.

Assessment of QTc and Risk of Torsades de Pointes in Ventricular Conduction Delay and Pacing: A Review of the Literature and Call to Action

BACKGROUND

Assessment of the heart rate-corrected QT-interval on the 12-lead electrocardiogram when prescribing medications known to increase the risk of Torsades de Pointes has become a common part of consultation-liaison psychiatry practice.

OBJECTIVES

Highlighted by a patient who experienced psychiatric decompensation due to inaccurate interpretation of QTc prolongation in the setting of a wide QRS complex, we aimed to describe the approach to QTc interpretation in patients with ventricular conduction delay.

METHODS

We reviewed the current literature on the approach to assessment of prolonged repolarization in patients with ventricular conduction delay due to bundle branch block (BBB) and ventricular pacing.

RESULTS

Physicians of any specialty may perform initial electrocardiogram interpretation and should be proficient in the definition, recognition, and understanding of the basic pathophysiology of electrocardiographic abnormalities. We discuss current approaches to assessment of the QT-interval in patients with a wide QRS complex due to bundle branch block and ventricular pacing, including bivariate QTc modification, univariate QT-interval modifications, and use of the JT-interval.

CONCLUSIONS

The QT-interval is prolonged ipso facto in patients with a wide QRS complex from ventricular conduction delay/ventricular pacing and must be adjusted for QRS duration. Multiple formulae have been proposed to account for wide QRS complex in this setting with no single universally accepted methodology. We suggest the use of either the Bogossian formula or JT-interval followed by Hodges or Framingham heart-rate correction to adjust for a wide QRS complex. It is critical that the C-L psychiatrist be able to identify a wide QRS complex on the electrocardiogram, understand implications for accurate assessment of prolonged depolarization, and apply an appropriate correction methodology.

Body Surface Potential Mapping During Heart Ventricular Repolarization in Male Swimmers and Untrained Persons Under Hypoxic and Hypercapnic Hypoxia

Ivonina, Natalya I., Andrey A. Fokin, and Irina M. Roshchevskaya. Body surface potential mapping during heart ventricular repolarization in male swimmers and untrained persons under hypoxic and hypercapnic hypoxia. High Alt Med Biol. 00:000-000, 2021. Background: In swimmers, as a result of prolonged breath-holding during swimming, first hypoxic hypoxia (HH) and then hypercapnic hypoxia (HCH) occurs, which may influence the electrical activity of the heart (EAH). What type of normobaric hypoxia more strongly affects the EAH-normocapnic HH or HCH? Methods: The electrical activity of swimmers' hearts (n = 7) and untrained persons (n = 10) was studied by using electrocardiography (ECG) and body surface potential mapping (BSPM) during the period of ventricular repolarization at baseline, at normocapnic HH, at HCH, and in the recovery period. Results: HH led to more significant changes in the EAH in all participants in comparison with HCH. There was no change in the amplitude of T wave_ECG at hypoxic and HCH, but a change in the amplitude of the minimum was noted in BSPM. The minimum in athletes changed by the end of the exposure (from -0.40 ± 0.12 mV to -0.26 ± 0.11 mV, p = 0.001); in the control, it decreased earlier (after 8 minutes of exposure to HH, the amplitude of the minimum was -0.24 ± 0.08 mV, p = 0.026). With HH, the duration of the QT interval in athletes was shortened due to the shortening of the J-Tpeak (from 250 to 188 ms, p = 0.001) and the Tpeak-Tend (from 98 to 86 ms) intervals. In controls, the decrease in the QT interval was due to the J-Tpeak shortening only (from 280 to 200 ms, p = 0.026). Conclusions: In the study of the effect of hypoxia on the EAH during ventricular repolarization, the use of the BSPM has proven to be more informative than the use of traditional ECG. When using potential mapping, more significant changes in ventricular repolarization at HH than at HCH were revealed, whereas the parameters changed less in swimmers compared with the baseline than in controls during both exposures.

Effects of Antipsychotics on Arrhythmogenic Parameters in Schizophrenia Patients: Beyond Corrected QT Interval

PURPOSE

Antipsychotic drugs have been implicated as risk factors for QT prolongation, which is a predictor of sudden cardiac death. However, the QT interval is considered an imperfect marker for proarrhythmic risk. Recently, improved methods, namely, QT dispersion (QTD), QTD ratio (QTDR), T wave peak-to-end interval (Tp-e), Tp-e/QT ratio and Tp-e/QTc ratio, have been regarded as proarrhythmic risk markers. We attempted to reevaluate the risk of sudden cardiac death due to antipsychotics use by measuring these improved evaluation methods.

PATIENTS AND METHODS

We retrospectively evaluated QTc, QTD, QTDR, Tp-e, Tp-e/QT ratio and Tp-e/QTc ratio from the medical records of 410 patients with schizophrenia diagnosed by the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision, or 5th Edition. Information on drugs administered was obtained from medical records. We investigated the correlation between each index on ECG and medication, such as antipsychotics, prescribed to participants with linear regression analysis. We also compared each index between 235 healthy controls and 235 patients matched for age and sex.

RESULTS

Positive correlations between QTc and levomepromazine and brexpiprazole were identified. Levomepromazine and lithium were positively correlated with QTD. Levomepromazine, quetiapine, asenapine, clozapine and carbamazepine were positively correlated with QTDR. Levomepromazine, olanzapine, brexpiprazole and lithium were positively correlated with Tp-e. Olanzapine, brexpiprazole and lithium were positively correlated with the Tp-e/QT ratio. Olanzapine, brexpiprazole and lithium were positively correlated with Tp-e/QTc ratio. Significant differences in all indexes were noted between the patients and healthy controls.

CONCLUSION

According to our results, the prediction of the risk of sudden cardiac death by each index was inconsistent. We should evaluate the predictive factor of ventricular arrhythmia according to various electrocardiogram indexes because QTc alone could not identify the risk of sudden cardiac death.

Assessment of Ventricular Repolarization in Sickle Cell Anemia Patients: The Role of QTc Interval, Tp-e Interval and Tp-e/QTc Ratio and Its Gender Implication

Background

Many specific and non-specific electrocardiographic abnormalities including ventricular arrhythmias have been reported in subjects with sickle cell anemia (SCA). In SCA patients, cardiac electrical abnormalities may be the leading cause of increased risk of arrhythmias. The corrected QT (QTc) interval, peak to the end of the T wave (Tp-e) interval and associated Tp-e/QTc ratio are promising measures of altered ventricular repolarization and increased arrhythmogenesis risk.

Aim

This study assessed ventricular repolarization abnormalities in subjects with SCA using the QTc interval, Tp-e interval and Tp-e/QTc ratio, and also evaluated the gender differences in these parameters, as well as their determinants.

Methods

Sixty subjects with SCA and 60 healthy control subjects, matched for age and gender, were studied. All participants underwent physical examination, hematological and biochemical evaluation, and 12-lead electrocardiography (ECG) recording. QT and Tp-e intervals were measured from the ECG, and the QTc interval was calculated using Bazett’s formula. Tp-e/QT and Tp-e/QTc ratios were also derived.

Results

QT and QTc intervals were prolonged in subjects with SCA. Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio were prolonged in male SCA subjects, with a paradoxical shortening in female SCA subjects. Plasminogen activator inhibitor-1 (PAI-1) was an independent determinant of QTc, while body mass index (BMI) was an independent determinant of both Tp-e interval and Tp-e/QTc ratio.

Conclusion

Our results suggest an elevated risk for ventricular arrhythmogenesis in male SCA subjects. Furthermore, increased BMI and PAI-1 level are possible markers of ventricular repolarization abnormalities in SCA subjects.

Tp-e and (Tp-e)/QT ratio as a non-invasive risk factors for malignant ventricular arrhythmia in patients with idiopathic ventricular premature complexes

Background

To evaluate the role of Tp‐e and (Tp‐e)/QT ratio in differentiating benign ventricular premature complex (VPC) and malignant polymorphic ventricular tachycardia (PVT).

Methods

From January 2017 to December 2017, patients with documented polymorphic ventricular tachycardia (PVT) or ventricular fibrillation (VF) were consecutive included and classified as PVT/VF group. Sixty age‐ and sex‐matched healthy individuals were recruited as comparative control and subdivided into non‐VPC and VPC group. Clinical characteristics and Tp‐e and Tp‐e/QT ratio between the three groups were compared.

Results

Tp‐e and (Tp‐e)/QT ratio were significantly higher in patients of PVT/VF group compared with the other two groups (P < .001). Episodes of syncope were more frequent in patients with PVT/VF (P < .05). The sensitivity and specificity of a Tp‐e interval ≥86 ms for malignant arrhythmias triggered by VPCs were 88% and 66%, respectively, while the sensitivity and specificity of the Tp‐e/QT ratio ≥0.24 were 82% and 70%, respectively. Five patients complained recurrence of syncope in the PVT/VF group and 1 patient died with mean follow‐up of 18 months.

Conclusion

Tp‐e interval and the Tp‐Te/QT ratio is significantly increased in patients with PVT/VF and may be used as a novel non‐invasive marker of differentiating malignant and benign VPC.

Correlation between apnea-hypopnea index and Tp-Te interval, Tp-Te/QT, and Tp-Te/QTc ratios in obstructive sleep apnea

Background

Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder associated with important cardiovascular complications including ventricular arrhythmias. Tp‐Te interval, Tp‐Te/QT, and Tp‐Te/QTc ratios are repolarization indices representing ventricular arrhythmogenic potential. These parameters are associated with ventricular arrhythmias and sudden cardiac death. The aim of this study was to investigate the correlation between apnea–hypopnea index and Tp‐Te, Tp‐Te/QT, and Tp‐Te/QTc in OSA.

Methods

We screened a total of 280 patients who underwent overnight polysomnography (PSG) between the years 2012–2017 at our institution. Patients were assigned into four groups based on severity of apnea–hypopnea index: 70 with apnea–hypopnea index (AHI) <5 (control group), 71 with 5 ≤ AHI < 15, 63 with 15 ≤ AHI < 30, and 76 with AHI ≥ 30. Tp‐Te, Tp‐Te/QT, and Tp‐Te/QTc were measured.

Results

Compared to control group, repolarization parameters were significantly prolonged in other groups (Tp‐Te interval: 68.3 ± 6.8, 71.8 ± 6.3, 79.1 ± 5.5, and 85.1 ± 6.4 ms, p < .001; Tp‐Te/QT ratio: 167.5 ± 12.7, 181.7 ± 13.0, 202.2 ± 10.0 and 219.4 ± 13.5, p < .001; Tp‐Te/QTc ratio: 151.1 ± 16.6, 167.6 ± 16.6, 193.7 ± 14.4, and 225.5 ± 17.0, p < .001). There was a significant trend toward higher Tp‐Te, Tp‐Te/QT, and Tp‐Te/QTc across higher AHI categories. In a univariate regression analysis, body mass index, smoking status, Tp‐Te, and Tp‐Te/QTc were significantly associated with the severity of AHI in OSA. Tp‐Te (OR 1.629, 95% CI 1.393–1.906, p < .001), Tp‐Te/QTc (OR 1,333 95% CI 1.247–1.424, p < .001), and smoking status (OR 5.771, 95% CI 1.025–32.479, p = .047) were found to be significant independent predictors of severity of AHI in a multivariate analysis, after adjusting for other risk parameters.

Conclusions

Our study showed that Tp‐Te, Tp‐Te/QT, and Tp‐Te/QTc were prolonged in patients with OSA. There was significant correlation between apnea–hypopnea index and these parameters.

No Association Between T-peak to T-end Interval on the Resting ECG and Long-Term Incidence of Ventricular Arrhythmias Triggering ICD Interventions

Background and Objectives

Potential of using the T-peak to T-end (TpTe) interval as an electrocardiographic parameter reflecting the transmural dispersion of ventricular repolarization (TDR) to identify patients (pts.) with higher risk of malignant ventricular arrhythmias (MVA) for better selection of candidates for implantable cardioverter-defibrillator (ICD) in primary prevention (PP) of sudden cardiac death (SCD) remains controversial. The primary objective of this study was to investigate the relationship between the TpTe interval in patient’s preimplantation resting 12-lead electrocardiogram (ECG) and the incidence of MVA resulting in appropriate ICD intervention (AI). The secondary objective was to assess its relationship to overall mortality.

Methods

A total of 243 consecutive pts. with severe left ventricular (LV) systolic dysfunction after myocardial infarction (MI) with a single-chamber ICD for PP of SCD from one implantation center were included. Excluded were all pts. with any other disease that could interfere with the indication of ICD implantation. Primarily investigated intervals were measured manually in accordance with accepted methodology. Data on ICD interventions were acquired from device interrogation during regular outpatient visits. Survival data were collected from the databases of health insurance and regulatory authorities.

Results

We did not find a significant relationship between the duration of the TpTe interval and the incidence of MVA (71.5 ms in pts. with MVA vs. 70 ms in pts. without MVA; p = 0.408). Similar results were obtained for the corrected TpTe interval (TpTec) and the ratio of TpTe to QT interval (76.3 ms vs. 76.5 ms; p = 0.539 and 0.178 vs. 0.181; p = 0.547, respectively). There was also no significant difference between the duration of TpTe, TpTec and TpTe/QT ratio in pts. groups by overall mortality (71.5 ms in the deceased group vs. 70 ms in the survivors group; HR 1.01; 95% CI, 0.99–1.02; p = 0.715, 76.3 ms vs. 76.5 ms; HR 1.01; 95% CI, 0.99–1.02; p = 0.208 and 0.178 vs. 0.186; p = 0.116, respectively).

Conclusion

This study suggests no significant association of overall or MVA-free survival with ECG parameters reflecting TDR (TpTe, TpTec) in patients with systolic dysfunction after MI and ICD implanted for primary prevention.

Temporal Variability in Electrocardiographic Indices in Subjects With Brugada Patterns

Introduction

Patients with Brugada electrocardiographic (ECG) patterns have differing levels of arrhythmic risk. We hypothesized that temporal variations in certain ECG markers may provide additional value for risk stratification. The present study evaluated the relationship between temporal variability of ECG markers and arrhythmic outcomes in patients with a Brugada pattern ECG. Comparisons were made between low-risk asymptomatic subjects versus high-risk symptomatic patients with a history of syncope, ventricular tachycardia (VT) or ventricular fibrillation (VF).

Methods

A total of 81 patients presenting with Brugada patterns were recruited. Serial ECGs and electronic health records from January 2004 to April 2019 were analyzed. Temporal variability of QRS interval, J point-T_peak interval (JTp), T_peak-T_end interval (Tp-e), and ST elevation (STe) in precordial leads V1-3, in addition to RR-interval from lead II, was assessed using standard deviation and difference between maximum and minimum values over the serial ECGs.

Results

Patients presenting with type 1 Brugada ECG pattern initially had significantly higher variability in JTp from lead V2 (SD: 33.5 ± 13.8 vs. 25.2 ± 11.5 ms, P = 0.009; max-min: 98.6 ± 46.2 vs. 78.3 ± 47.6 ms, P = 0.047) and ST elevation in lead V1 (0.117 ± 0.122 vs. 0.053 ± 0.030 mV; P = 0.004). Significantly higher variability in Tp-e interval measured from lead V3 was observed in the VT/VF group compared to the syncope and asymptomatic groups (SD: 20.5 ± 8.5 vs. 16.6 ± 7.3 and 14.7 ± 9.8 ms; P = 0.044; max-min: 70.2 ± 28.9 vs. 56.3 ± 29.0 and 43.5 ± 28.5 ms; P = 0.011).

Conclusion

Temporal variability in ECG indices may provide additional value for risk stratification in patients with Brugada pattern.

The relationship between T-wave peak-to-end interval and hemodynamic parameters in patients with pulmonary arterial hypertension

BACKGROUND

T-wave peak-to-end interval (TPEI) is a measure of repolarization dispersion on surface electrocardiogram (ECG). TPEI has been reported as a prognostic parameter with heart disorders. In this study, we aimed to evaluate the relationship between echocardiogram-derived right heart parameters, right heart catheterization (RHC) measurements, and TPEI in patients with precapillary pulmonary arterial hypertension (PAH).

METHODS

Thirty-eight patients (29 females and 9 males, mean age of 54.9 ± 10.9 years) who had undergone RHC for a preliminary diagnosis of pulmonary hypertension (PH) were included in the study. We performed transthoracic echocardiography (TTE), and resting 12-lead ECG was recorded before RHC. TPEI was measured from leads of V1-V6, DII, DIII, and aVF, and these values are averaged to obtain the global TPEI.

RESULTS

Duration of TPEI was significantly correlated with mean PAP, pulmonary vascular resistance (PVR), and cardiac index (CI). Longer TPEI was associated with higher N terminal probrain natriuretic peptide (NT pro-BNP) level, lower 6-min walk distance (6MWD), and lower tricuspid annular plane systolic excursion (TAPSE).

CONCLUSION

Prolongation of TPEI could be a new predictor of adverse outcome in PAH and may provide additional prognostic information for patients with PAH.

Effect of angiotensin/neprilysin inhibition on ventricular repolarization and clinical arrhythmogenesis

Background: The most common reason for sudden cardiac death in heart failure is malign ventricular arrhythmias. LCZ 696 improves hospitalization and sudden cardiac death outcomes in heart failure, however mechanisms in preventing sudden cardiac death are still unknown. There is little information available assessing effect of LCZ 696 on Tp-e interval and related calculations. In this study, we aimed to investigate the impact of Sacubitril/valsartan therapy on Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio in heart failure patients and its reflections on clinical arrhythmogenesis. Methods: The study was designed as a prospective observational fashion. 265 patients with implantable cardioverter-defibrillator (ICD), who were on regular follow up at Samsun Training and Research Hospital Outpatient Heart Failure Clinic, were validated for the study. Clinical, echocardiographic, electrocardiogram and device data before initiation and six months after dose optimizing were obtained. Results: Stroke volume, cardiac output and ejection fraction significantly improved after LCZ 696 treatment. T wave related parameters, QT and QTC intervals significantly diminished. Furthermore, there was a negative correlation between baseline Tp-e interval duration and the absolute percentile increase of stroke volume(r:-0.234, p: 0.042) and cardiac output (r: -0.240, p: 0.037). Conclusion: In our study, switching Renin-Angiotensin-Aldosterone-System inhibitor with Angiotensin receptor/neprilysin inhibitor was associated with increase in left ventricle performance and decrease of sustained ventricular arrhythmias that required ICD shocks. These positive findings were accompanied by improvements in surface electrocaridogram changes such as Tp-e and related indices.

Effect of Methadone on Cardiac Repolarization in Japanese Cancer Patients: A Longitudinal Study

INTRODUCTION

Methadone is known to prolong the QT interval, which could induce lethal arrhythmias such as torsades de pointes. To determine the risk of ventricular arrhythmias in cancer patients using methadone, we measured QT dispersion (QTD) and Tpeak-Tend (TpTe) before and after methadone administration and evaluated the correlations between methadone dosage and cardiac repolarization.

METHODS

We conducted a retrospective observational study with 19 patients undergoing follow-up for cancer pain with methadone. Electrocardiogram (ECG) recordings were obtained from the patients at methadone initiation and 1 week, 1 month, and 2 months later. The QT, corrected QT (QTc), QTD, QTc dispersion (QTcD), TpTe, TpTe/QT, and TpTe/QTc were measured manually via ECG records and analyzed using a repeated measures one-way ANOVA. The correlations between these ECG parameters and each methadone dosage were determined using Spearman's rank correlation coefficient.

RESULTS

The QTD, QTcD, TpTe/QT, and TpTe/QTc remained unchanged, while TpTe was prolonged significantly at 2 months (initiation: 82 ± 17 ms; 2 months: 106 ± 20 ms, p = 0.018). In addition, there was a positive correlation between TpTe and methadone dosage (rs = 0.4, p = 0.041).

CONCLUSIONS

The findings suggested that small or modest doses of methadone could exert dose-dependent effects on cardiac repolarization in cancer patients.

TRIAL REGISTRATION

UMIN Clinical Trials Registry, UMIN000034519.

An Observational Study of QTc Prolongation in Critically Ill Patients: Identification of Incidence and Predictors

AIMS

Despite the importance of abnormal QTc interval values in intensive care unit (ICU) patients, there is a paucity of information on this topic. The current study was designed to identify the incidence and predictors of QTc prolongation in medical (M), surgical (S), and emergency (E) ICUs.

MATERIALS AND METHODS

A prospective observational study was conducted for 6 months. Patients more than 18 years old who admitted to MICU, SICU, and EICU were included in the study. Electrocardiogram (ECG) was taken on day 1, 3, and 5 of ICU admission. The QTc intervals >460 ms in male and >470 ms in female and increased >60 ms above baseline were considered QTc prolongation. Comparative analysis was done between two groups of patients (normal vs prolonged QTc). Logistic regression models were carried out to determine the predictors of QTc prolongation.

RESULTS

Incidence of QTc prolongation was 6.5, 9.8, and 15.7% on day 1, 3, and 5 of ICU admission, respectively. On day 1, the history of alcohol addiction and the reason of ICU admission were associated with a prolonged QTc. A significant association was demonstrated between administration of azithromycin and QTc prolongation on day 3. High serum creatinine and hospitalization in EICU were predictors of QTc prolongation on day 5 of ICU admission.

CONCLUSION

The QTc prolongation is relatively common among patients admitted to ICUs and its incidence increases with increasing length of hospital stay. Predictors of QTc prolongation may be affected by the duration of ICU admission. Physicians should consider these predictors particularly before prescribing QTc-prolonging drugs.

HOW TO CITE THIS ARTICLE

Farzanegan B, Hosseinpoor Z, Baniasadi S, Seyyedi SR, Rajabi M. An Observational Study of QTc Prolongation in Critically Ill Patients: Identification of Incidence and Predictors. Indian J Crit Care Med 2020;24(4):270-275.

Effects of Septoplasty on Tp-e Interval and Tp-e/QT Ratio in Patients With Nasal Septal Deviation

OBJECTIVES

There are multiple nasal airway pathologies leading to upper airway obstruction, and one of the most common ones is nasal septum deviation (NSD). Our study aimed to evaluate the effect of nasal septal surgery in patients with NSD on ventricular arrhythmogenesis using the novel electrocardiographic parameters, Tp-e interval, and Tp-e/QT ratio.

METHODS

This retrospective cross-sectional study included 102 consecutive patients diagnosed with NSD. All participants completed a validated outcomes instrument (the NOSE scale), echocardiographic and electrocardiographic evaluation before and 3 months after septoplasty. The degree of nasal septal deviation was evaluated with the Dreher classification.

RESULTS

All of the electrocardiography parameters (except heart rate and QTmin) were significantly decreased with the septoplasty operation. Electrocardiographic parameters have significantly decreased especially in marked NSD patients. (Δ = difference between the preoperative and postoperative values) ΔNOSE was positively correlated both ΔcTp-e (r = 0.348, P < .001) and ΔcTp-e/QT values (r = 0.536, P < .001).

CONCLUSION

Consequently, marked NSD was associated with increased risk of arrhythmogenesis, which were too much improved after septoplasty. So, treatment of especially marked NSD not only reduces otolaryngological complaints, but also leads to improvement of ventricular repolarization parameters.

Handling of Ventricular Fibrillation in the Emergency Setting

Ventricular fibrillation (VF) and sudden cardiac death (SCD) are predominantly caused by channelopathies and cardiomyopathies in youngsters and coronary heart disease in the elderly. Temporary factors, e.g., electrolyte imbalance, drug interactions, and substance abuses may play an additive role in arrhythmogenesis. Ectopic automaticity, triggered activity, and reentry mechanisms are known as important electrophysiological substrates for VF determining the antiarrhythmic therapies at the same time. Emergency need for electrical cardioversion is supported by the fact that every minute without defibrillation decreases survival rates by approximately 7%–10%. Thus, early defibrillation is an essential part of antiarrhythmic emergency management. Drug therapy has its relevance rather in the prevention of sudden cardiac death, where early recognition and treatment of the underlying disease has significant importance. Cardioprotective and antiarrhythmic effects of beta blockers in patients predisposed to sudden cardiac death were highlighted in numerous studies, hence nowadays these drugs are considered to be the cornerstones of the prevention and treatment of life-threatening ventricular arrhythmias. Nevertheless, other medical therapies have not been proven to be useful in the prevention of VF. Although amiodarone has shown positive results occasionally, this was not demonstrated to be consistent. Furthermore, the potential proarrhythmic effects of drugs may also limit their applicability. Based on these unfavorable observations we highlight the importance of arrhythmia prevention, where echocardiography, electrocardiography and laboratory testing play a significant role even in the emergency setting. In the following we provide a summary on the latest developments on cardiopulmonary resuscitation, and the evaluation and preventive treatment possibilities of patients with increased susceptibility to VF and SCD.

Effects of nicorandil infusion on ECG parameters in patients with unstable angina pectoris and percutaneous coronary intervention

Background

Percutaneous coronary intervention (PCI) is effective in treating patients with acute coronary syndrome (ACS) but is associated with some serious complications. Nicorandil is an anti‐anginal agent acting to improve microvascular circulation and to increase coronary blood flow. The objective of this article is to evaluate the effects of intracoronary injection followed with continuous intravenous injection of nicorandil on ECG parameters in patients with unstable angina pectoris (UA) undergoing PCI.

Methods

A single‐center, self‐controlled clinical trial was conducted at the Second Hospital of Tianjin Medical University between January 2019 and April 2019. Sixty‐three consecutive patients with UA who received coronary angiography and selective PCI were enrolled. ECG was recorded and analyzed before and 24 hr after nicorandil infusion.

Results

Patients were divided into three groups: control group (n = 23, aged 63.43 ± 12.55 years), short‐term, and prolonged use with nicorandil group (n = 20 and 20, aged 66.45 ± 8.06 years and 65.80 ± 9.49 years, respectively). Clinical characteristics and ECG parameters were similar before PCI among three groups (p > .05). In nicorandil treatment groups, intervals of QTd and Tp‐e in patients post‐PCI were significantly shorter than that in control and pre‐PCI (p < .05).

Conclusions

Nicorandil infusion reduces QTd and Tp‐e interval in patients with UA. Further studies will be needed to determine whether these electrophysiological changes are associated with a reduction of ventricular arrhythmias and improved outcomes.

Predictive value of Tpeak-Tend interval for ventricular arrhythmia and mortality in heart failure patients with an implantable cardioverter-defibrillator: A cohort study

BACKGROUND

Tpeak-Tend interval (TpTe), a measurement of transmural dispersion of repolarization (TDR), has been shown to predict ventricular tachyarrhythmia in cardiac resynchronization therapy with defibrillator (CRT-D) patients. However, the ability of TpTe to predict ventricular tachyarrhythmia and mortality for heart failure patients with a cardioverter-defibrillator (ICD) is not clear. The purpose of this study was to assess the predictive ability of TpTe in heart failure patients with ICD.

METHODS AND RESULTS

We enrolled 318 heart failure patients treated after ICD. Patients were divided into 3 groups according to their post-implantation TpTe values and were evaluated every 6 months. The primary endpoint was appropriate ICD therapy. The secondary endpoint was all-cause mortality. During long-term follow-up, the TpTe > 110 ms group (n = 111) experienced more VT/VF episodes (45%) and all-cause mortality (25.2%) than the TpTe 90-110 ms group (n = 109) (26.4%, 14.5%) and TpTe < 90 ms group (n = 98) (11.3%, 11.3%) (overall P < .05, respectively). In Cox regression, longer post-implantation TpTe was associated with an increased number of VT/VF episodes [HR: 1.017; 95% CI: 1.008-1.026; P < .001], all-cause mortality [HR: 1.015; 95% CI: 1.004-1.027; P = .010] and the combined endpoint [HR: 1.018; 95%CI: 1.010-1.026; P < .001].

CONCLUSIONS

Post-implantation TpTe was an independent predictor of both ventricular arrhythmias and all-cause mortality in heart failure patients with an implanted ICD.

Comparison of QT interval variability of coronary patients without myocardial infarction with that of patients with old myocardial infarction

BACKGROUND

The significant association of myocardial ischemia with elevated QT interval variability (QTV) has been reported in myocardial infarction (MI) patients. However, the influence of the time course of MI on QTV has not been investigated systematically.

METHOD

Short-term QT and RR interval time series were constructed from the 5 min electrocardiograms of 49 coronary patients without MI and 26 patients with old MI (OMI). The QTV, heart rate variability (HRV), and QT-RR coupling of the two groups were analyzed using various time series analysis tools in the time- and frequency-domains, as well as nonlinear dynamics.

RESULTS

Nearly all of the tested QTV indices for coronary patients with OMI were higher than those for patients without MI. However, no significant differences were found between the two groups in any of the variables employed to assess the HRV and QT-RR coupling. All of the markers that showed statistical significances in univariate analyses still possessed the capabilities of distinguishing between the two groups even after adjusting for studied baseline characteristics, including the coronary atherosclerotic burden.

CONCLUSIONS

The results suggested that the QTV increased in coronary patients with OMI compared to those without MI, which might reflect the influence of post-MI remodeling on the beat-to-beat temporal variability of ventricular repolarization. The non-significant differences in the HRV and QT-RR couplings could indicate that there were no differences in the modulation of the autonomic nervous system and interaction of QT with the RR intervals between the two groups.

Assessment of Tp-Te Interval and Tp-Te/Qt Ratio in Patients with Aortic Aneurysm

BACKGROUND

Arrhythmic disorders in the aortic aneurysm (AA) have been rarely reported.

AIM

The study aimed to assess the repolarisation indices of ventricular arrhythmia (VA) (mainly Tp-Te interval and Tp-Te/QT ratio) in patients with AA.

METHODS

A group of 98 patients with AA and 75 patients as control were recruited. Many of indices of ventricular arrhythmia were assessed.

RESULTS

Many of indices like QT, QTc, QTpc, Tp-Te/QT, Tp-Te/QTc, Tp-Tec/QTc, S-Tp, S-Tpc, S-Te, S-Tec and fQRS were found to be significantly different in AA group (for all P < 0.05). However, QTp, mean Tp-Te and Tp-Tec were not found different (for all P < 0.05). Aortic diameter (Ao-D) was found to have a positive correlation with QTc, QTpc, S-Tp, S-Tpc, S-Te, S-Tec, fQRS (for all P < 0,05) and negative correlation withTp-Te/QT (P = 0.047). The best cut-off level for prediction of Tp-Te ≥100 ms was found the Ao-D > 43.5 mm in ROC analysis (AUC: 0.69; P = 0.151) with sensitivity 60% and specificity 79.6%.

CONCLUSIONS

Although our study did not find any differences for mean Tp-Te interval between groups, many of other indexes of TDR were found to be significantly different. Ao-D was found to have significant correlations with many indices.

Comparing of Tp-Te Interval and Tp-Te/Qt Ratio in Patients with Preserved, Mid-Range and Reduced Ejection Fraction Heart Failure

BACKGROUND

Heart failure (HF) is classified in three class: HF with preserved EF (HFpEF); normal or LVEF ≥ 50%, HF with reduced EF (HFrEF); LEVF < 40% and newly HF mid-range EF (HFmrEF); LVEF 40-49%. On Electrocardiography (ECG) T wave, Tpeak-Tend (Tp-Te) interval reflects transmural dispersion of repolarisation (TDR) which of these indexes have been proposed as predictors of risk for ventricular arrhythmia (VA) in many cardiac diseases.

AIM

Aim of this study to asses these indices of TDR among three HF class.

METHODS

Total of 192 patients were included in this study.

RESULTS

Many of indices like Tp-Te, Tp-Te/QT wasn't different between groups (P > 0.05). But mean Q-Tpeak (QTp), S-Tend (S-Te) and S-Tpeak (S-Tp) were found significantly different between groups (P < 0.05). Again S-Te was found different according to having fragmented QRS (fQRS) on ECG (P = 0.031). Comparing to mitral inflow E/A parameters showed significant differences for Tp-Te, Tp-Tec, Tp-Te/QT, Tp-Te/QTc and Tp-Tec/QTc parameters. Finally, we found correlations between S-Te and white blood cell (WBC) (r = - 0.171; P = 0.037) and S-Tp and WBC (r = - 0.170; P = 0.038) and between S-Te and fQRS (r = 0.158; P = 0.031).

CONCLUSIONS

We didn't find differences for many of indices of TDR like Tp-Te interval between groups except QTp, S-Te, S-Tp intervals. Also, S-Te and fQRS showed significant correlation. For prediction of ventricular arrhythmia and cardiovascular death newer indexes on ECG are needed to be established in the future which will make us facilitate to distinguish high risk patients.

Noninvasive assessment of left-ventricular diastolic electromechanical coupling in hypertensive heart disease

BACKGROUND

There is a need to stratify patients who may develop heart failure because of the current "heart failure pandemic". We hypothesized that noninvasive assessment of diastolic electromechanical coupling by electrocardiography and Doppler echocardiography may be clinically useful for risk stratification of hypertensive patients who may develop heart failure.

METHODS

We measured the time from the peak to end of the T wave (TpTe) as an electrophysiological parameter, and peak early diastolic mitral flow (E) and lateral annular (e') velocities as mechanical parameters in 109 patients with hypertension. Relationships between these parameters and their association with the prognosis were evaluated.

RESULTS

The e' was inversely correlated with TpTe (p < 0.001) and QTc (p < 0.014), whereas E/e' was positively correlated with TpTe (p < 0.001) and QTc (p < 0.001). The TpTe predicted patients with E/e' > 12. There were 24 cardiovascular events during follow-up (57 ± 20 months), and Kaplan-Meier analysis showed that outcome was worse (p = 0.003) in patients with higher E/e' than lower E/e'; however, there was no difference between patients with longer TpTe (≧72 ms) and shorter TpTe (< 72 ms).

CONCLUSION

The correlation of TpTe with e' and E/e' in hypertensive patients suggests that these parameters reflect diastolic ventricular electromechanical coupling. The E/e' predicted outcome, and an elevated E/e' should be suspected when TpTe is prolonged (> 72 ms). Noninvasive evaluation of diastolic electromechanical coupling is clinically useful in patients with hypertension for predicting their outcome.

Progressive increase of the Tpeak-Tend interval is associated with ischaemia-induced ventricular fibrillation in a porcine myocardial infarction model

Aims

Repolarization indices of ECG have been widely assessed as predictors of ventricular arrhythmias. However, little is known of the dynamic changes of these parameters during continuous monitoring in acute ischaemic episodes. The objective of the study was to evaluate repolarization-related predictors of ventricular fibrillation (VF) during progression of experimental myocardial infarction.

Methods and results

Myocardial infarction was induced in 27 pigs by 40-min balloon inflation in the left anterior descending coronary artery, and 12-lead ECG was continuously recorded. Rate-corrected durations of the total Tpeak-Tend intervals measured from the earliest T-wave peak to the latest T-wave end in any lead were determined at baseline and at minute 1, 2, 5, and then every 5th minute of occlusion. There were 7 early (1-3 min) and 10 delayed (15-30 min) VFs in 16 pigs. Baseline Tpeak-Tend did not differ between animals with and without VF. Tpeak-Tend interval rapidly increased immediately after balloon inflation and was greater in VF-susceptible animals at 2-15 min compared with the animals that never developed VF (P < 0.05). Tpeak-Tend was tested as a predictor of delayed VFs. Median Tpeak-Tend at 10th min of occlusion was higher in delayed VF group (n = 10) than in animals without VF (n = 11): 138 [IQR 121-148] ms vs. 111 [IQR 106-127] ms, P = 0.02. Tpeak-Tend  ≥123 ms (10th min) predicted delayed VF episodes with HR = 4.5 95% CI 1.1-17.8, P = 0.031.

Conclusion

Tpeak-Tend prolongation during ischaemia progression predicts VF in the experimental porcine myocardial infarction model and warrants further testing in clinical settings of acute coronary syndromes.

Investigation of the Proarrhythmic Effects of Antidepressants according to QT Interval, QT Dispersion and T Wave Peak-to-End Interval in the Clinical Setting

OBJECTIVE

Some antidepressants have been implicated as risk factors for QT prolongation, which is a predictor of sudden cardiac death. However, the QT interval is considered an imperfect biomarker for proarrhythmic risk. Therefore, we reevaluated the risk of sudden cardiac death due to antidepressants using improved.

METHODS

, namely, QT dispersion (QTD), T wave peak-to-end interval (Tp-e), and Tp-e/QT ratio.

METHODS

We compared the effects of antidepressants on QTc (QT/RR1/3), QTD, Tp-e, and Tp-e/QT ratio in 378 patients with mood disorder. We also compared each index between 165 healthy controls and 215 randomly selected age-matched patients.

RESULTS

Age (p<0.01), sex (p<0.05), tricyclic antidepressant (TCA) use (p<0.05), and clomipramine (p<0.01) and mianserin (p<0.05) use in particular, significantly associated with a prolonged QTc. We also found that age (p<0.01), TCA use (p<0.05), and clomipramine (p<0.01) and mianserin (p<0.05) use in particular, significantly prolonged QTD. However, there was no correlation between each variable and Tp-e or Tp-e/QT ratio. Significant differences in QTc and QTD were found between the patients and healthy controls.

CONCLUSION

From our results, prediction of risk of sudden cardiac death by QTD, Tp-e, or Tp-e/QT ratio was inconsistent. Increased QTD may be more suitable for predicting sudden cardiac death due to antidepressants.

Optimal method of measuring the T-peak to T-end interval for risk stratification in primary prevention

Aims

Several published investigations demonstrated that a longer T-peak to T-end interval (Tpe) implies increased risk for ventricular tachyarrhythmia (VT/VF) and mortality. Tpe has been measured using diverse methods. We aimed to determine the optimal Tpe measurement method for screening purposes.

Methods and results

We evaluated 305 patients with LVEF ≤ 35% and an implantable cardioverter-defibrillator implanted for primary prevention. Tpe was measured using seven different methods described in the literature, including six manual methods and the automated algorithm '12SL', and was corrected for heart rate. Endpoints were VT/VF and death. To account for differences in the magnitude of Tpe measurements, results are expressed in standard deviation (SD) increments. We evaluated the clinical utility of each measurement method based on predictive ability, fraction of immeasurable tracings, and intra- and interobserver correlation. >Over 31 ± 23 months, 82 (27%) patients had VT/VF, and over 49 ± 21 months, 91 (30%) died. Several rate-corrected Tpe measurement methods predicted VT/VF (HR per SD 1.20-1.34; all P < 0.05), and nearly all methods (both corrected and uncorrected) predicted death (HR per SD 1.19-1.35; all P < 0.05). Optimal predictive ability, readability, and correlation were found in the automated 12SL method and the manual tangent method in lead V2.

Conclusion

For the prediction of VT/VF, the utility of Tpe depends upon the measurement method, but for the prediction of mortality, most published Tpe measurement methods are similarly predictive. Heart rate correction improves predictive ability. The automated 12SL method performs as well as any manual measurement, and among manual methods, lead V2 is most useful.

Tpeak-Tend/QT interval predicts ST-segment resolution and major adverse cardiac events in acute ST-segment elevation myocardial infarction patients undergoing percutaneous coronary intervention

Elevated ST-segment and increased Tpeak-Tend interval (Tp-e) were prognostic predictors in major adverse cardiac events (MACEs) in ST-segment elevation myocardial infarction (STEMI). The electrophysiologic relationship between them during percutaneous coronary intervention (PCI) needs to elucidate.Patients with STEMI admitted to hospital were prospectively evaluated. ST-segment resolution (STR) (defined as ≥50% reduction as the complete-STR [CSTR] group, <50% as incomplete-STR [ISTR] group), Tp-e interval, and ratio of Tp-e to QT interval (Tp-e/QT) were measured, calculated and analyzed with MACEs.Tp-ec interval (corrected Tp-e interval, P < .001) and Tp-e/QT ratio (P < .001) were significantly increased by myocardial infarction and partly recovered post-PCI. Patients with ISTR showed more increased Tp-ec interval (P < .001) and Tp-e/QT ratio (P < .001) than those in CSTR groups post-PCI. In multivariate analysis and receiver operating characteristic curves analysis, Tp-e/QT was an independent and strongest predictor for STR. STR and electrocardiogram parameters with a cutoff value for predicting STR showed prognostic value for MACE in STEMI in Kaplan-Meier survival analysis.Both STR and change of Tp-e parameters were not only predictors of arrhythmia, but also prognostic factors of MACE in patients with STEMI after PCI.

Ventricular repolarization wave variations during the amiodarone treatment course

The aim of this study was to assess ventricular repolarization wave variations during the amiodarone treatment course for patients with ventricular arrhythmias and atrial fibrillation.Sixty-nine patients with ventricular arrhythmias and 9 patients with persistent atrial fibrillation were treated with intravenous injection of a 150 mg loading dose of amiodarone, followed by 1 mg/minute for 6 hours and 0.5 mg/minute for 48 hours. After the initial 24 hours of intravenous injection, amiodarone was also administered orally at a dose of 0.2 g tid for 1 week; followed by 0.2 g bid for 1 week and 0.2 g qd for maintenance. During the procedure, the heart rate, QT, QTc, QTd, QTcd TpTe, TpTe-c, TpTe-d, TpTe/QT, and QTp were measured on days 1, 3, 7, 10, 14, 17, and 20 of amiodarone treatment.The control rate of arrhythmias was 91.0% (71/78). The heart rate dropped significantly on the 7th day after treatment initiation and reached the minimal value on day 14. The QT interval was prolonged from day 3; TpTe was prolonged from day 7 to day 14; QTp was prolonged from day 1 to day 20. The longest QT interval (441.2 ± 33.9 ms) and TpTe (95.0 ± 18.0 ms) occurred on day 14. QTc, QTd, QTcd, TpTe-c, TpTe-d, and TpTe/QT showed no significant changes throughout the treatment.Amiodarone lowers the heart rate, prolongs QT and QTp intervals, and transiently prolongs TpTe. However, it has no effects on QTc, QTd, QTcd, TpTe-c, TpTe-d or TpTe/QT. Amiodarone prolongs QT interval evenly, showing no effects on repolarization dispersion. TpTe/QT is a better indicator of ventricular transmural repolarization dispersion compared with TpTe.

TpTe and TpTe/QT: novel markers to predict sudden cardiac death in ESRD?

INTRODUCTION

Reliable markers to predict sudden cardiac death (SCD) in patients with end stage renal disease (ESRD) remain elusive, but electrocardiogram (ECG) parameters may help stratify patients. Given their roles as markers for myocardial dispersion especially in high risk populations such as those with Brugada syndrome, we hypothesized that the Tpeak to Tend (TpTe) interval and TpTe/QT are independent risk factors for SCD in ESRD.

METHODS

Retrospective chart review was conducted on a cohort of patients with ESRD starting hemodialysis. Patients were US veterans who utilized the Veterans Affairs medical centers for health care. Average age of all participants was 66 years and the majority were males, consistent with a US veteran population. ECGs that were performed within 18 months of dialysis initiation were manually evaluated for TpTe and TpTe/QT. The primary outcomes were SCD and all-cause mortality, and these were assessed up to 5 years following dialysis initiation.

RESULTS

After exclusion criteria, 205 patients were identified, of whom 94 had a prolonged TpTe, and 61 had a prolonged TpTe/QT interval (not mutually exclusive). Overall mortality was 70.2% at 5 years and SCD was 15.2%. No significant difference was observed in the primary outcomes when examining TpTe (SCD: prolonged 16.0% vs. normal 14.4%, p=0.73; all-cause mortality: prolonged 55.3% vs. normal 47.7%, p=0.43). Likewise, no significant difference was found for TpTe/QT (SCD: prolonged 15.4% vs. normal 15.0%, p=0.51; all-cause mortality: prolonged 80.7% vs. normal 66.7%, p=0.39).

CONCLUSIONS

In ESRD patients on hemodialysis, prolonged TpTe or TpTe/QT was not associated with a significant increase in SCD or all-cause mortality.

Association of Tp-Te/QT Ratio With Ventricular Tachycardia in Patients With Idiopathic Outflow Tract Ventricular Premature Contraction

BACKGROUND

Idiopathic outflow tract ventricular premature contraction (VPC) can evolve into ventricular tachycardia (VT) via triggered activity mechanism. Transmural dispersion of repolarization (TDR) might play a role in idiopathic outflow tract VT by inducing phase 2 early afterdepolarization (EAD) and serve as the functional substrate for VT. Tp-Te/QT ratio as an arrhythmogenesis index has been reported to be associated with the incidence of ventricular arrhythmia. This study aims to investigate the association between Tp-Te/QT ratio with VT incidence in idiopathic outflow tract VPC.

METHODS

Observational research with cross sectional design was conducted. VT episodes were retrospectively tracked from electrocardiogram (ECG), treadmill test (TMT), Holter monitor and electrophysiology study data in Sardjito Hospital of patients with idiopathic outflow tract VPC during September to October 2017. Tp-Te/QT was defined as the time from the peak of T wave to the intersection between the tangent and isoeectric line, divided with QT interval. Tp-Te/QT ratio measurement was performed in leads V4, V5 and V6 by single observer. Tp-Te/QT ratio was categorized into increased (> 0.25) and normal (< 0.25). Chi-square and logistic regression test were performed.

RESULTS

Out of 46 patients, there were 28 patients who had VT. Increased Tp-Te/QT ratio of lead V4 was found in 11 patients, the increased ratios in leads V5 and V6 were found in 13 patients. The prevalence ratio (PR) of Tp-Te/QT ratio to VT incidence in lead V4 was 2.059 (95% CI: 1.464 - 2.895; P = 0.007), while in leads V5 and V6 was 2.200 (95% CI: 1.514 - 3.197; P = 0.002). Tp-Te/QT ratios in leads V4, V5 and V6 were not significantly different and equally strong in predicting VT events (P < 0.001; 95% CI). Adjustment of confounding factor hypertension with multivariate test gave insignificant results (PR: 1.290; 95% CI: 0.444 - 3.747).

CONCLUSIONS

Increased Tp-Te/QT ratio in idiopathic outflow tract VPC patients was associated with higher prevalence ratio for VT, although this was affected by hypertension. Leads V4, V5 and V6 were equally strong in predicting VT events.

Tpeak-Tend dispersion as a predictor for malignant arrhythmia events in patients with vasospastic angina

BACKGROUND

Tpeak-Tend interval (Tp-e interval) in electrocardiogram (ECG) has been reported to predict malignant arrhythmia events (MAE) in ST-segment elevation myocardial infarction and ion channelopathy. Tp-e interval and other ECG parameters as predictors for MAE was evaluated in patients with vasospastic angina (VA).

METHODS AND RESULTS

Sixty-two patients with VA (Non-MAE group) and 20 patients with VA complicated by MAE (MAE group) were enrolled in our Division of Cardiology between January 2010 and December 2015. Continuous variables were analyzed by t-test and categorical variables by Chi-square analysis. Patients with MAE showed greater QTc (corrected QT interval) dispersion (P=0.005), Tp-ec (corrected Tp-e) interval (P=0.001), Tp-ec dispersion (P<0.001) and Tp-e/QT ratio (P<0.001) than those in non-MAE groups when ST-segment elevated. After elevated ST-segment returned, there were no significant differences in these ECG parameters between two groups (All P>0.05). At univariate binary logistic regression analysis QTc dispersion (odds ratio(OR)=1.133; P=0.013), Tp-ec (OR=1.058; P=0.003), Tp-e/QT (OR=1.403; P=0.001), and Tp-ec dispersion (OR=1.497; P=0.004) were significantly associated with MAE. At multivariable logistic regression analysis, Tp-ec dispersion remained a predictor of MAE. Receiver operating characteristic (ROC) curve analysis showed that only AUC (Area under curve) of Tp-ec dispersion had significant difference with those in QTc dispersion (P<0.001), Tp-ec (P=0.003), and Tp-e/QT ratio (P=0.012), respectively.

CONCLUSIONS

QTc dispersion, Tp-ec, Tp-e/QT and Tp-ec dispersion were significantly increased in VA patients with MAE than those without MAE when coronary spasm was onset. Prolonged Tp-ec dispersion was the best discriminators and a strong independent predictor of MAE in VA patients.

Evaluation of the Tp-Te Interval, QTc and P-Wave Dispersion in Patients With Coronary Artery Ectasia

Background

Coronary artery ectasia (CAE) is defined as a diffuse dilatation of the diameter of the ectatic segment of the coronary artery, 1.5 times greater than that of the adjacent segment. The Tp-Te interval, P-wave and QTc dispersions are relatively new electrocardiographic markers associated with an increased risk of developing arrhythmias. Despite CAE increasing in prevalence in recent years, there is a sparsity of data available about its arrhythmogenic effect. The aim of the study was to evaluate QTc, P-wave dispersion and Tp-Te and Tp-Te/QT ratio in patients with CAE.

Methods

A retrospective comparative study was designed for consecutive age- and sex-matched patients. Twenty patients with isolated CAE (group 1) and 20 control subjects (group 2), with normal coronary arteries, were included. All patients presented with chest pain and coronary angiogram was indicated. Outcome measures included Tp-Te interval, Tp-Te/QT ratio, QTc dispersion and P-wave dispersion. Measurement of electrocardiogram (ECG) parameters was conducted using standardized digital online software. Descriptive and inferential statistics were performed.

Results

Mean Tp-Te (95.5 ± 9.01 ms) and Tp-Te/QT ratio (0.22 ± 0.02) were significantly prolonged in CAE group (Tp-Te: 84 ± 5.62 ms, P = 0.00009; Tp-Te/QT ratio: 0.20 ± 0.01, P = 0.00004). In addition, QTc (31.2 ± 3.71 ms) and P-wave dispersion (31.9 ± 5.46 ms) were significantly increased in comparison to the control group (QTc: 27.6 ± 2.82 ms, P = 0.00532 and 20 ± 3.77 ms, P = 0.00003 respectively). However, there was no difference in ventricular activation time (VAT) between groups.

Conclusions

CAE ECGs were found to be associated with increased Tp-Te, Tp-Te/QT ratio, QTc intervals and P-wave dispersions. This may suggest that CAE existence has a pro-arrhythmogenic nature.

Heart Failure and Sudden Cardiac Death

The Centers for Diseases Control and Prevention estimates that 5.7 million adults in the United States suffer from heart failure and 1 in 9 deaths in 2009 cited heart failure as a contributing cause. Almost 50% of patients who are diagnosed with heart failure die within 5 years of diagnosis. Cardiovascular disease is a public health burden. The prognosis of patients with heart failure has improved significantly. However, the risk for death remains high. Managing sudden death risk and intervening appropriately with primary or secondary prevention strategies are of paramount importance.

The T-peak-to-T-end interval: a novel ECG marker for ventricular arrhythmia and appropriate ICD therapy in patients with hypertrophic cardiomyopathy

INTRODUCTION

Hypertrophic cardiomyopathy (HCM) is associated with an increased risk of sudden cardiac death (SCD) primarily due to ventricular arrhythmia (VA). In patients (pts.) with a high risk of SCD, the implantation of an intracardiac cardioverter defibrillator (ICD) is thus indicated. Previous studies suggest that a prolonged interval between the peak and the end of the T wave, T-peak to T-end (TpTe), is associated with an elevated risk of VA and SCD in various clinical settings. The aim of our study was to evaluate the association between TpTe and VA in HCM pts. with a previously implanted ICD.

METHODS

In 40 HCM pts. (51.4 ± 16.4 years; 62.5% men), TpTe was measured using the baseline digital standard resting 12-lead ECG during sinus rhythm. VA was assessed by device follow-up.

RESULTS

Within 41.8 ± 35.1 months, 7 (17.5%) pts. had VA leading to appropriate therapy (AT), 7 pts. (17.5%) had non-sustained VA, and 26 pts. (65.0%) had no VA. The maximum TpTe was significantly prolonged in pts. with VA leading to AT compared to pts. without VA (101.3 ± 19.6 vs. 79.9 ± 15.3 ms; p = 0.004). Maximum TpTe was associated with an elevated risk of VA leading to AT (hazard ratio per 10 ms increase 1.63; 95% CI 1.04-2.54; p = 0.031) and pts. with a maximum TpTe ≤ 78 ms were without any VA leading to AT during follow-up. There was no correlation of maximum TpTe to other clinical parameters in our patient cohort.

CONCLUSION

A prolonged TpTe is associated with VA and AT in HCM. Our findings suggest that TpTe can possibly serve as a marker for ventricular arrhythmogenesis in pts. with HCM and assessment of TpTe might, therefore, optimize SCD risk stratification.

Prognostic Value of a New Marker of Ventricular Repolarization in Cirrhotic Patients

Background

There is still debate about the relationship between changes in ventricular repolarization on the surface electrocardiogram and cirrhosis severity.

Objective

To study the relationship between variables related to ventricular repolarization and the clinical severity of the cirrhotic disease.

Methods

We selected 79 individuals with hepatic cirrhosis, classified according to the Child-Pugh-Turcotte criteria (Child A, B, and C). We measured the QT and corrected QT (QTc) intervals, and the interval between the peak and the end of the T wave (TpTe), and we identified their minimum, maximum, and mean values in the 12-lead electrocardiogram. We also calculated the dispersion of the QT (DQT) and QTc (DQTc) intervals.

Results

In 12 months of clinical follow-up, nine subjects underwent hepatic transplantation (Child A: 0 [0%]; Child B: 6 [23.1%]; Child C: 3 [18.8%]; p = 0.04) and 12 died (Child A: 3 [12.0%]; Child B: 4 [15.4%]; Child C: 5 [31.3%]; p = 0.002). No significant differences were observed between the cirrhotic groups related to the minimum, maximum, and mean values for the QT, QTc, TpTe, DQT, and DQTc intervals. A minimum TpTe interval ≤ 50 ms was a predictor for the composite endpoints of death or liver transplantation with a sensitivity of 90% and a specificity of 57% (p = 0.005). In the Cox multivariate analysis, the Child groups and a minimum TpTe of ≤ 50 ms were independent predictors of the composite endpoints.

Conclusion

The intervals QT, QTc, DQT, DQTc, and TpTe have similar distributions between different severity stages in cirrhotic disease. The TpTe interval proved to be a prognostic marker in subjects with cirrhosis, regardless of disease severity (NCT01433848).

Low Iron Stores in Otherwise Healthy Children Affect Electrocardiographic Markers of Important Cardiac Events

Both an excess of iron and iron deficiency (ID) may lead to significant cardiac problems. Parameters that represent ventricular repolarization heterogeneity, like QT dispersion (QTd), corrected QT dispersion (QTcd), the interval between the peak and the end of the T wave (Tp-e), and Tp-e dispersion, have not been evaluated in otherwise healthy children with low iron levels before. Here we assessed the effects of low iron storage on P wave dispersion (PWd), QTd, Tp-e intervals, and Tp-e dispersion in otherwise healthy children. We prospectively reviewed 283 patients who were referred to pediatric cardiology department for cardiac evaluation due to murmurs and who were found to have no structural heart disease. The patients were divided into three groups according to their ferritin levels: Group 1: ferritin <15 ng/mL (n = 58); Group 2: ferritin 15-25 ng/mL (n = 80); Group 3: ferritin >25 ng/mL (n = 145). P wave duration (PW), QT and Tp-e intervals, and PW, QT, corrected QT (QTc), and Tp-e dispersions were significantly higher in patients whose ferritin level was <15 ng/mL. A negative correlation was found between ferritin level and QT and QTc intervals, and QT, QTc, and Tp-e dispersions. Our results showed that a low serum ferritin level is associated with changes in some ECG parameters such as prolonged PWd, Tp-e interval, QT, QTc, and Tp-e dispersions in otherwise healthy children, and studies of other populations indicated that these parameters may predict arrhythmias in selected patients. These patients may be considered at some risk of developing arrhythmias. Therefore, careful evaluation of these ECG parameters is necessary in otherwise healthy children with low iron stores.

Age- and sex-based reference ranges for non-invasive ventricular repolarisation parameters

BACKGROUND

Some electrocardiographic parameters are able to assess indirectly ventricular repolarisation homogeneity. It is consequently essential to discriminate between normal and abnormal values in clinical decision-making. Considering there is still not a consensus about normal cut-off values, the aim of this study was to document reference intervals in all age groups of a healthy population, providing for age- and sex-percentile tables, which can be used easily and quickly in clinical practice.

METHODS

We evaluated repolarisation markers in 606 sex-matched participants aged 1 day-94 years. Each subject underwent a 12-lead electrocardiogram at rest, and the following parameters were measured: QT, corrected QT, QTpeak, Tpeak-Tend, Tpeak-Tend dispersion, Tpeak-Tend/QT and QTpeak/QT ratio.

RESULTS

A relationship was demonstrated between age and QTpeak, Tpeak-Tend, QT and QTc. In children, QTpeak, Tpeak-Tend and QT intervals increased linearly with age. In adolescents, all the three parameters remained stable. In adults, QTpeak and QT showed a further significant increase. On the contrary, Tpeak-Tend interval was longer in adults aged between 20 and 64 years than in participants aged 65 years or over, but the difference was not statistically significant. Male vs female participants showed longer Tpeak-Tend intervals; this sex difference was not statistically significant at birth and during childhood, whereas it was in adolescents and in adults.

CONCLUSIONS

Repolarisation parameters showed age- and sex-based variations, which are important to know to differentiate normal from pathological values.