INTRODUCTION: Repolarization dispersion in the right ventricular outflow tract (RVOT) contributes to the type-1 electrocardiographic (ECG) phenotype of Brugada syndrome (BrS), while data on the significance and feasibility of mapping repolarization dispersion in BrS patients are scarce. Moreover, the role of endocardial repolarization dispersion in BrS is poorly investigated. We aimed to assess endocardial repolarization patterns through an automated calculation of activation recovery interval (ARI) estimated on unipolar electrograms (UEGs) in spontaneous type-1 BrS patients and controls; we also investigated the relation between ARI and right ventricle activation time (RVAT), and T-wave peak-to-end interval (Tpe) in BrS patients. METHODS: Patients underwent endocardial high-density electroanatomical mapping (HDEAM); BrS showing an overt type-1 ECG were defined as OType1, while those without (latent type-1 ECG and LType1) received ajmaline infusion. BrS patients only underwent programmed ventricular stimulation (PVS). Data were elaborated to obtain ARI corrected with the Bazett formula (ARIc), while RVAT was derived from activation maps. RESULTS: 39 BrS subjects (24 OType1 and 15 LTtype1) and 4 controls were enrolled. OType1 and post-ajmaline LType1 showed longer mean ARIc than controls (306 ± 27.3 ms and 333.3 ± 16.3 ms vs. 281.7 ± 10.3 ms, p = .05 and p < .001, respectively). Ajmaline induced a significant prolongation of ARIc compared to pre-ajmaline LTtype1 (333.3 ± 16.3 vs. 303.4 ± 20.7 ms, p < .001) and OType1 (306 ± 27.3 ms, p < .001). In patients with type-1 ECG (OTtype1 and post-ajmaline LType1) ARIc correlated with RVAT (r = .34, p = .04) and Tpec (r = .60, p < .001), especially in OType1 subjects (r = .55, p = .008 and r = .65 p < .001, respectively). CONCLUSION: ARIc mapping demonstrates increased endocardial repolarization dispersion in RVOT in BrS. Endocardial ARIc positively correlates with RVAT and Tpec, especially in OType1.
Action Potentials , Algorithms , Brugada Syndrome , Electrocardiography , Electrophysiologic Techniques, Cardiac , Endocardium , Heart Rate , Predictive Value of Tests , Humans , Male , Female , Middle Aged , Brugada Syndrome/physiopathology , Brugada Syndrome/diagnosis , Endocardium/physiopathology , Adult , Time Factors , Case-Control Studies , Ajmaline/administration & dosage , Automation , Ventricular Function, Right , Cardiac Pacing, Artificial , Aged , Signal Processing, Computer-Assisted
The most common cause of death in patients with Duchenne muscular dystrophy (DMD) is cardiomyopathy. Our aim was to investigate the relationship between the Tpeak-Tend (Tp-e) interval and the premature ventricular contraction (PVC) burden and therefore early arrhythmic risk and cardiac involvement in DMD patients. Twenty-five patients with DMD followed by pediatric cardiology were included in the study. Those with a frequency of <1% PVC in the 24 h Holter were assigned to Group 1 (n = 15), and those with >1% were assigned to Group 2 (n = 10). Comparisons were made with healthy controls (n = 27). Left ventricular ejection fraction (LVEF) was lowest in Group 2 and highest in the control group (p < 0.001). LV end-diastolic diameter was greater in Group 2 than in Group 1 and the control group (p = 0.005). Pro-BNP and troponin levels were higher in Group 1 and Group 2 than in the control group (p = 0.001 and p < 0.001, respectively). Tp-e interval was longer in Group 2 compared to Group 1 and the control group (p < 0.001). The LVEF (OR 0.879, 95% CI 0.812-0.953; p = 0.002) and Tp-e interval (OR 1.181, 95% CI 1.047-1.332; p = 0.007) were independent predictors of PVC/24 h frequency of >1%. A Tp-e interval > 71.65 ms predicts PVC > 1%, with a sensitivity of 80% and a specificity of 90% (AUC = 0.842, 95% CI (0.663-1.000), p = 0.001). Determination of Tp-e prolongation from ECG data may help in the determination of cardiac involvement and early diagnosis of arrhythmic risk in DMD.
Abstract Purpose: The Tpeak-Tend interval of the T wave has emerged as a new electrocardiographic marker of increased transmural dispersion of ventricular repolarization. We aimed to determine the presence of cardiac conduction system disorders in patients with systemic arterial hypertension (SAH) who have altered Tpeak-Tend interval of the T wave. Methods: The 67 patients with SAH were divided into two groups. Those with prolonged (≥ 77 ms) Tpeak-Tend intervals, 21 (31%) patients were in the study group. Those with normal (< 77 ms) Tpeak-Tend intervals, 46 (69%) patients were in the control group. Alteration of ventricular repolarization manifested as a prolongation of the Tpeak-Tend interval was detected by computerized electrocardiographic analysis tools. Results: The median value of QRS complex duration was significantly wider in the study group as compared to the control group (110 ± 12 ms vs. 94 ± 8 ms p < 0.001). There was a significantly greater incidence of left anterior hemiblock in the study group (14% vs. 0% p < 0.04). The median value of the QTc interval was significantly greater in the study group (440 ± 26 vs. 422 ± 15 p < 0.01). There was a significantly greater incidence of patients with prolonged QTc interval in the study group (33% vs. 11% p < 0.02). The median value of the Tpeak-Tend interval was significantly greater in the study group (84 ± 5 ms vs. 65 ± 4 ms p < 0.001), as well as, the Tpeak-Tend/QTc ratio in the study group (0.19 ± 0.1 vs. 0.16 ± 0.1 p < 0.001). Conclusion: There is a significantly greater ventricular repolarization disorders and abnormalities of the cardiac conduction system in SAH patients who possess altered Tpeak-Tend interval of the T wave.
Resumen Objetivo: El intervalo Tpico-Tfinal de la onda T es un marcador electrocardiográfico de la dispersión transmural aumentada de la repolarización ventricular. Investigamos la presencia de trastornos del sistema de conducción cardíaca en pacientes con hipertensión arterial sistémica (HA) que poseen alterado el intervalo Tpico-Tfinal de la onda T. Métodos: Los 67 pacientes con HA fueron divididos en dos grupos. Aquellos con intervalos de Tpico-Tfinal prolongados (≥ 77 ms), 21 (31%) pacientes (grupo de estudio). Aquellos con intervalos normales (< 77 ms) Tpico-Tfinal, 46 (69%) pacientes (grupo control). Los intervalos Tpico-Tfinal fueron medidos por herramientas de análisis electrocardiográfico computarizado. Resultados: El valor mediano de la duración del complejo QRS fue significativamente más amplio en el grupo de estudio (110 ± 12 ms vs. 94 ± 8 ms p < 0.001). Hubo una incidencia significativamente mayor de hemibloqueo anterior izquierdo en el grupo de estudio (14% vs. 0% p < 0.04). El valor mediano del intervalo QTc fue significativamente mayor en el grupo de estudio (440 ± 26 vs. 422 ± 15 p < 0.01). Hubo una incidencia significativamente mayor de pacientes con intervalo QTc prolongado en el grupo de estudio (33% vs. 11% p < 0.02). El valor mediano del intervalo Tpico-Tfinal fue significativamente mayor en el grupo de estudio (84 ± 5 ms vs. 65 ± 4 ms p < 0.001), así como el cociente Tpico-Tfinal/QTc (0.19 ± 0.1 vs. 0.16 ± 0.1 p < 0.001). Conclusión: Existe una alteración de la repolarización ventricular significativamente mayor y anomalías del sistema de conducción cardíaca en pacientes con HA que poseen alteración del intervalo Tpico-Tfinal de la onda T.
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.
PURPOSE: The Tpeak-Tend interval of the T wave has emerged as a new electrocardiographic marker of increased transmural dispersion of ventricular repolarization. We aimed to determine the presence of cardiac conduction system disorders in patients with systemic arterial hypertension (SAH) who have altered Tpeak-Tend interval of the T wave. METHODS: The 67 patients with SAH were divided into two groups. Those with prolonged (≥ 77 ms) Tpeak-Tend intervals, 21 (31%) patients were in the study group. Those with normal (< 77 ms) Tpeak-Tend intervals, 46 (69%) patients were in the control group. Alteration of ventricular repolarization manifested as a prolongation of the Tpeak-Tend interval was detected by computerized electrocardiographic analysis tools. RESULTS: The median value of QRS complex duration was significantly wider in the study group as compared to the control group (110 ± 12 ms vs. 94 ± 8 ms p < 0.001). There was a significantly greater incidence of left anterior hemiblock in the study group (14% vs. 0% p < 0.04). The median value of the QTc interval was significantly greater in the study group (440 ± 26 vs. 422 ± 15 p < 0.01). There was a significantly greater incidence of patients with prolonged QTc interval in the study group (33% vs. 11% p < 0.02). The median value of the Tpeak-Tend interval was significantly greater in the study group (84 ± 5 ms vs. 65 ± 4 ms p < 0.001), as well as, the Tpeak-Tend/QTc ratio in the study group (0.19 ± 0.1 vs. 0.16 ± 0.1 p < 0.001). CONCLUSION: There is a significantly greater ventricular repolarization disorders and abnormalities of the cardiac conduction system in SAH patients who possess altered Tpeak-Tend interval of the T wave.
OBJETIVO: El intervalo Tpico-Tfinal de la onda T es un marcador electrocardiográfico de la dispersión transmural aumentada de la repolarización ventricular. Investigamos la presencia de trastornos del sistema de conducción cardíaca en pacientes con hipertensión arterial sistémica (HA) que poseen alterado el intervalo Tpico-Tfinal de la onda T. MÉTODOS: Los 67 pacientes con HA fueron divididos en dos grupos. Aquellos con intervalos de Tpico-Tfinal prolongados (≥ 77 ms), 21 (31%) pacientes (grupo de estudio). Aquellos con intervalos normales (< 77 ms) Tpico-Tfinal, 46 (69%) pacientes (grupo control). Los intervalos Tpico-Tfinal fueron medidos por herramientas de análisis electrocardiográfico computarizado. RESULTADOS: El valor mediano de la duración del complejo QRS fue significativamente más amplio en el grupo de estudio (110 ± 12 ms vs. 94 ± 8 ms p < 0.001). Hubo una incidencia significativamente mayor de hemibloqueo anterior izquierdo en el grupo de estudio (14% vs. 0% p < 0.04). El valor mediano del intervalo QTc fue significativamente mayor en el grupo de estudio (440 ± 26 vs. 422 ± 15 p < 0.01). Hubo una incidencia significativamente mayor de pacientes con intervalo QTc prolongado en el grupo de estudio (33% vs. 11% p < 0.02). El valor mediano del intervalo Tpico-Tfinal fue significativamente mayor en el grupo de estudio (84 ± 5 ms vs. 65 ± 4 ms p < 0.001), así como el cociente Tpico-Tfinal/QTc (0.19 ± 0.1 vs. 0.16 ± 0.1 p < 0.001). CONCLUSIÓN: Existe una alteración de la repolarización ventricular significativamente mayor y anomalías del sistema de conducción cardíaca en pacientes con HA que poseen alteración del intervalo Tpico-Tfinal de la onda T.
Arrhythmias, Cardiac , Long QT Syndrome , Humans , Heart Conduction System , Cardiac Conduction System Disease , Electrocardiography , Long QT Syndrome/complications
Background and Objectives: Early repolarization pattern (ERP) has recently been shown to be related with an increased risk of ventricular arrhythmias in susceptible individuals. Materials and Methods: We studied the ERP-associated ECG changes, with potential clinical relevance, in 220 young (age 22.1 ± 1.6 years), healthy, male subjects using 12-lead ECG recordings. A total of 38 subjects (17.3%) fulfilled the diagnostic criteria for ERP, and a total of 90 ECG characteristics were compared between the groups of subjects with and without ERP. Results: None of the ECGs were pathological, and 22 ECG parameters differed significantly (p < 0.05) between the subjects with and without ERP. Among them, the P wave-related parameters (e.g., average P wave duration: 101.5 ± 9.2 ms vs. 106.8 ± 9.9 ms, p = 0.004) and the presence of fragmented QRS complexes (67.6% vs. 92.1%, p = 0.002) revealed a potential propensity for atrial and ventricular arrhythmogenesis. The time-domain parameters of repolarization, those not corrected for QRS duration, showed shorter values (e.g., Tpeak-Tend interval: 70.9 ± 8.1 ms vs. 67.8 ± 8.0 ms, p = 0.036), reflecting the accelerated repolarization. Conclusions: Certain ECG characteristics seem to be more associated with ERP. The clinical significance of this finding at the individual level needs further prospective investigations.
Arrhythmias, Cardiac , Electrocardiography , Adult , Arrhythmias, Cardiac/diagnosis , Humans , Male , Young Adult
Background: it has been shown that vitamin B12 deficiency, which can cause hematological and neuropsychiatric disorders, may also be associated with cardiac autonomic dysfunction, heart rate variability, endothelial dysfunction, and a decrease in myocardial deformation. Aims: the aim of our study is to evaluate the relationship between vitamin B12 levels and electrocardiographic repolarization disorders, which are indicators of arrhythmogenic predisposition in healthy individuals. Methods: our study population consisted of 214 healthy adults. Considering the distribution of vitamin B12 levels and accepting 25 % and 75 % percentiles as the cut-off values, the participants were divided into 3 groups. Laboratory, echocardiography and electrocardiography (ECG) measurements were compared between three groups. ECG measurements were performed manually and Tpeak-Tend (Tp-e), Tp-e corrected (Tp-ec), QT and QT corrected (QTc) intervals were calculated. Results: the patients in Group 1 (vitamin B12 < 253 pg/ml) were found to have significantly higher QT and QTc dispersions, Tp-e interval, Tp-e/QT and Tp-e/QTc ratios when compared to those in Group 2 (253 pg/ml < vitamin B12 > 436 pg/ml) and Group 3 (vitamin B12 > 436 pg/ml). On the other hand, a negative significant correlation was detected between vitamin B12 levels and Tp-e, Tp-e/QT, Tp-e/QTc ratios, QT and QTc dispersions. Conclusion: a low level of vitamin B12 in healthy individuals can be a significant indicator of arrhythmogenic susceptibility. A close follow-up of these subjects in terms of arrhythmogenic predisposition can be useful (AU)
Fundamento: se ha demostrado que la deficiencia de vitamina B12, que puede causar trastornos hematológicos y neuropsiquiátricos, también puede estar asociada con disfunción autonómica cardíaca, variabilidad de la frecuencia cardíaca, disfunción endotelial y disminución de la deformación miocárdica. Objetivos: el objetivo de nuestro estudio es evaluar la relación entre los niveles de vitamina B12 y los trastornos de repolarización electrocardiográfica que son indicadores de predisposición arritmogénica en individuos sanos. Métodos: la población del estudio fue de 214 adultos sanos. Considerando la distribución de los niveles de vitamina B12 y aceptando los percentiles del 25 % y 75 % como valores de corte, los participantes se dividieron en 3 grupos. Se compararon las mediciones de laboratorio, ecocardiografía y electrocardiografía (ECG) entre tres grupos. Las mediciones del ECG se realizaron manualmente y se calcularon los intervalos Tpeak-Tend (Tp-e), Tp-e corregido (Tp-ec), QT y QT corregido (QTc). Resultados: se encontró que los pacientes del grupo 1 (vitamina B12 < 253 pg/ml) tenían dispersiones QT y QTc, intervalo Tp-e, cocientes Tp-e/QT y Tp-e/QTc significativamente más altos cuando se compararon con los del grupo 2 (253 pg/ml < vitamina B12 > 436 pg/ml) y el grupo 3 (vitamina B12 > 436 pg/ml). Por otro lado, se detectó una correlación significativa negativa entre los niveles de vitamina B12 y las relaciones Tp-e, Tp-e/QT, Tp-e/QTc, dispersiones QT y QTc.Conclusión: el bajo nivel de vitamina B12 en los individuos sanos puede ser un indicador significativo de susceptibilidad arritmogénica. Un seguimiento estrecho de estos sujetos en términos de predisposición arritmogénica podría ser útil (AU)
Humans , Male , Female , Adult , Middle Aged , Aged , Electrocardiography , Vitamin B 12/blood , Ventricular Function/physiology , Arrhythmias, Cardiac/blood , Reference Standards , Retrospective Studies , Heart Rate , Biomarkers
BACKGROUND: The use of electrocardiography (ECG) is a practical method to evaluate the response to cardiac resynchronization therapy (CRT) implantation, as it is easily performed and saves time. AIM: This study aimed to assess the predictive value of the T-wave duration and Tpeak-Tend (Tp-e) interval following the CRT implantation administered to heart failure patients. METHODS: Sixty-seven patients with left ventricular ejection fraction ≤35, New York Heart Association (NYHA) class II-III, ambulatory class IV, normal sinus rhythm, who have complete left bundle branch block on ECG and treated with CRT were included in this study. Patients who have manifested a ≥10% improvement in ejection fraction following CRT implantation, were categorized as "responders", and the remaining patients were categorized as "non-responders". ECGs and echocardiograms were evaluated both six months before and after CRT implantation. RESULTS: The post-CRT QRS duration (P = 0.01), cQT interval (P = 0.005), T-wave (P <0.001), and Tp-e interval (P <0.001) were found to be significantly reduced in the responder group compared to the non-responder group. The receiver operating characteristics curve analyses revealed that the predictive optimal cut-off of the T-wave was <182 ms (P <0.001), and that of the Tp-e interval was <92 ms (P <0.001). CONCLUSIONS: T-wave and Tp-e interval may be independent predictors of a favorable CRT response in heart failure patients.
Cardiac Resynchronization Therapy , Heart Failure , Bundle-Branch Block/therapy , Electrocardiography , Heart Failure/therapy , Humans , Prognosis , Stroke Volume , Treatment Outcome , Ventricular Function, Left
BACKGROUND: Conflicting results have been described in the scientific literature regarding the relationship between electrocardiographic parameters and complications in patients with Takotsubo syndrome (TTS). Aim of the present study was to investigate whether there is an association between markers of ventricular repolarization and major adverse cardiovascular events (MACE) during hospitalisation. METHODS: A retrospective chart review was conducted on a sample of patients with diagnosis of TTS, based on the fulfilment of the revised Mayo Clinic criteria. MACE included acute heart failure, cardiogenic shock, sustained ventricular tachycardia, ventricular fibrillation, and death. The following parameters, assessed on the admission electrocardiogram, were analysed: ST-segment elevation, ST-segment depression, T wave inversion, presence of Q waves, QT interval, QT interval corrected for heart rate, QT-dispersion, Tpeak-Tend (Tpe) interval, Tpe dispersion, Tpe/QT ratio, and QTpeak/QT ratio. RESULTS: Patients with MACE, compared to patients without MACE, showed more commonly anterior ST-segment elevation and had significantly higher values of Tpe/QT ratio. Low ejection fraction and Tpe/QT ratio > 0.27 identified a sub-population of patients more likely to have MACE during hospitalisation. CONCLUSIONS: Tpe/QT ratio represents a useful electrocardiographic parameter in the acute phase of TTS.
Takotsubo Cardiomyopathy , Arrhythmias, Cardiac , Electrocardiography , Humans , Retrospective Studies , Takotsubo Cardiomyopathy/complications , Takotsubo Cardiomyopathy/diagnosis , Takotsubo Cardiomyopathy/epidemiology , Ventricular Fibrillation
We report a 77-year-old human on renal dialysis for end-stage renal disease with heart failure and atrial fibrillation (AF) complicated by a high ventricular frequency. The underlying disease was thought as tachycardia-induced-cardiomyopathy. Intravenous infusion of amiodarone was initiated, and direct current cardioversion succeeded in converting AF to sinus rhythm. Then, excessive increases in the QT and Tpeak-Tend (Tp-e) intervals were seen and hypokalemia induced by hemodialysis led to the development of numerous episodes of torsades de pointes (TdP). Magnesium repletion was effective in preventing TdP, while Tp-e intervals returned to the previous values 2 days after the discontinuation of amiodarone.
Amiodarone/adverse effects , Anti-Arrhythmia Agents/adverse effects , Cardiomyopathies/drug therapy , Torsades de Pointes/chemically induced , Aged , Amiodarone/therapeutic use , Anti-Arrhythmia Agents/therapeutic use , Electrocardiography/methods , Humans , Male , Torsades de Pointes/diagnosis
Repolarization heterogeneity (RH) is an intrinsic property of ventricular myocardium and the reason for T-wave formation on electrocardiogram (ECG). Exceeding the physiologically based RH level is associated with appearance of life-threatening ventricular arrhythmias and sudden cardiac death. In this regard, an accurate and comprehensive evaluation of the degree of RH parameters is of importance for assessment of heart state and arrhythmic risk. This review is devoted to comprehensive consideration of RH phenomena in terms of electrophysiological processes underlying RH, cardiac electric field formation during ventricular repolarization, as well as clinical significance of RH and its reflection on ECG parameters. The formation of transmural, apicobasal, left-to-right and anterior-posterior gradients of action potential durations and end of repolarization times resulting from the heterogenous distribution of repolarizing ion currents and action potential morphology throughout the heart ventricles, and the different sensitivity of myocardial cells in different ventricular regions to the action of pharmacological agents, temperature, frequency of stimulation, etc., are being discussed. The review is focused on the fact that RH has different aspects - temporal and spatial, global and local; ECG reflection of various RH aspects and their clinical significance are being discussed. Strategies for comprehensive assessment of ventricular RH using different ECG indices reflecting various RH aspects are presented.
BACKGROUND: Precordial T-wave inversion (TWI) is an important diagnostic criterion for arrhythmogenic right ventricular cardiomyopathy (ARVC). OBJECTIVE: This study aimed to characterize the initial repolarization features of definite ARVC in patients who first presented with right ventricular outflow tract ventricular arrhythmia (RVOT-VA) and TWI. METHODS: Patients who presented with RVOT-VA and TWI ≥ V2 were retrospectively assessed. The initial characteristics of repolarization between patients with and without a final diagnosis of definite ARVC during follow-up were compared. RESULTS: TWI ≥ V2 was observed in 61 of 553 patients (mean age: 44.1 ± 14.7 years; 14 men) with RVOT-VAs. After an average follow-up time of 54.9 ± 33.7 months, 31 (50.8%) patients were classified into the definite ARVC group and 30 (49.2%) into the non-definite ARVC group. The disappearance of precordial TWI ≥ V2 was observed in eight (13.1%) patients after the elimination of RVOT-VAs. In a multivariate analysis of the initial electrocardiogram features, only fragmented QRS [odds ratio (OR): 15.45, 95% confidence interval (CI): 1.61-148.26, p = 0.02] and precordial V2 TpTe interval (OR: 1.03, 95% CI: 1.01-1.06, p = 0.02) could independently predict definite ARVC during longitudinal follow-up. An initial V2 TpTe cutoff value > 88.5 ms could predict the final diagnosis of definite ARVC, with a sensitivity and specificity of 74.2% and 78.6%, respectively. CONCLUSIONS: Despite the high risk of ARVC in RVOT-VAs and TWI ≥ V2, "normalization" of TWI was observed after ventricular arrhythmia elimination in 13.1% of the patients. Fragmented QRS and longer V2 TpTe interval were associated with definite ARVC during longitudinal follow-up.
AIMS: To establish the indication for programmed ventricular stimulation (PVS) for asymptomatic patients with Brugada syndrome (BrS), we evaluated the prognostic significance of PVS based on abnormal electrocardiogram (ECG) markers. METHODS AND RESULTS: One hundred and twenty-five asymptomatic patients with BrS were included. We performed PVS at two sites of the right ventricle with up to three extrastimuli [two pacing cycle lengths and minimum coupling interval (MCI) of 180 ms]. We followed the patients for 133 months and evaluated ventricular fibrillation (VF) events. Fragmented QRS (fQRS) and Tpeak-Tend (Tpe) interval were evaluated as ECG markers for identifying high-risk patients. Fragmented QRS and long Tpe interval (≥100 ms) were observed in 66 and 37 patients, respectively. Ventricular fibrillation was induced by PVS in 60 patients. During follow-up, 10 patients experienced VF events. Fragmented QRS, long Tpe interval, and PVS-induced VF with an MCI of 180 ms or up to two extrastimuli were associated with future VF events (fQRS: P = 0.015, Tpe ≥ 100 ms: P = 0.038, VF induction: P < 0.001). However, PVS-induced VF with an MCI of 200 ms was less specific (P = 0.049). The frequencies of ventricular tachyarrhythmia events during follow-up were 0%/year with no ECG markers and 0.1%/year with no VF induction. The existence of two ECG factors with induced VF was strongly associated with future VF events (event rate: 4.4%/year, P < 0.001), and the existence of one ECG factor with induced VF was also associated (event rate: 1.3%/year, P = 0.011). CONCLUSION: We propose PVS with a strict protocol for asymptomatic patients with fQRS and/or long Tpe interval to identify high-risk patients.
Brugada Syndrome , Brugada Syndrome/diagnosis , Electrocardiography , Heart Ventricles , Humans , Prognosis , Ventricular Fibrillation/diagnosis
INTRODUCTION: In patients with early repolarization patterns on ECG, many researchers have studied to find predictors of fatal arrhythmia. However, there are no satisfying clinical predictors. We evaluated the value of the Tpeak -Tend interval on pseudo-ECG in canine myocardial wedge preparation models of early repolarization syndrome. METHODS AND RESULTS: Transmural pseudo-ECG and endocardial/epicardial action potentials were recorded from coronary-perfused canine left ventricular wedge preparations (n = 34). The Ito agonist NS5806 (8-10 µM), the calcium channel blocker verapamil (3 µM) and acetylcholine (2-3 µM) were used to mimic the disease model. A ventricular arrhythmia induction test was performed. QTpeak , QTend , Tpeak -Tend , and Tpeak -Tend /QTend were measured at 15 to 20 minutes after the provocative agent infusion. Polymorphic ventricular tachycardias (pVT) developed in 23 of the 34 preparations (67%). The maximal values of Tpeak -Tend and Tpeak -Tend /QTend were recorded just before pVT induction. At baseline, without the provocative agents, Tpeak -Tend and Tpeak -Tend /QTend were not different between pVT-induced and pVT-noninduced preparations. The Tpeak -Tend of the pVT-induced preparations was longer than that of non-induced preparations (58 ± 26.8 msec vs 33 ± 6.8 msec, P < .001). The Tpeak -Tend /QTend of pVT- induced preparations was larger than that of noninduced preparations (0.220 ± 0.1017 vs 0.128 ± 0.0312, P < .001). The transmural and epicardial dispersion of repolarization of pVT-induced preparations were larger than those of pVT-noninduced preparations. The transmural dispersion of repolarization showed a positive correlation with Tpeak -Tend . CONCLUSION: Tpeak -Tend predicted malignant ventricular arrhythmias in early repolarization syndrome models. Tpeak -Tend reflects the repolarization heterogeneity of ventricular myocardium.
Action Potentials , Electrocardiography , Heart Rate , Heart Ventricles/physiopathology , Tachycardia, Ventricular/diagnosis , Time Factors , Ventricular Fibrillation/diagnosis , Acetylcholine , Animals , Death, Sudden, Cardiac/etiology , Disease Models, Animal , Dogs , Endocardium/physiopathology , Female , Male , Pericardium/physiopathology , Predictive Value of Tests , Reproducibility of Results , Risk Factors , Tachycardia, Ventricular/chemically induced , Tachycardia, Ventricular/physiopathology , Ventricular Fibrillation/chemically induced , Ventricular Fibrillation/physiopathology , Verapamil
INTRODUCTION: Changes in thyroid hormone level can affect the cardiovascular system. The aim of this study was to show how the Tpeak -Tend (Tpe) interval, which is a new marker of ventricular arrythmia, is affected in patients who have become euthyroid following Levothyroxine treatment for hypothyroidism, as this has not been examined previously in literature. MATERIALS AND METHODS: This, cross-sectional study included a total of 119 females aged 18-45 years, separated into 3 groups as hypothyroid, euthyroid and control groups. For evaluation of the QTc and Tpe intervals, examination on precordial V5 lead was made of all the ECGs taken routinely on presentation of the patients. RESULTS: The Tpe and QTc intervals of the hypothyroid group were determined to be significantly prolonged compared to those of the euthyroid and control groups (p < 0.001) and the values of the euthyroid and control groups were similar. A positive correlation was determined between TSH levels and Tpe and QTc intervals. Tpe interval AUC = 0.801 (%95 CI: 0.719 - 0.884) was higher than that of QTc AUC = 0.689 (%95 CI: 0.591 - 0.786). CONCLUSIONS: The Tpe duration was evaluated in respect of the risk of arrythmia in hypothyroid patients. In patients who had become euthyroid, the Tpe interval was found to be similar to that of healthy individuals and was more predictive than QTc. In the light of these findings it can be recommended that measurement of the Tpe interval should be preferred to QTc as a marker of the arrythmogenic effect in hypothyroid patients.
Arrhythmias, Cardiac/blood , Hypothyroidism/drug therapy , Thyrotropin/blood , Thyroxine/therapeutic use , Adolescent , Adult , Arrhythmias, Cardiac/etiology , Case-Control Studies , Cross-Sectional Studies , Female , Humans , Hypothyroidism/blood , Hypothyroidism/complications , Middle Aged , Young Adult
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 (â§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.
Echocardiography, Doppler , Electrocardiography , Heart/diagnostic imaging , Hypertension/diagnostic imaging , Aged , Arrhythmias, Cardiac/epidemiology , Cardiovascular Diseases/mortality , Cerebral Infarction/epidemiology , Diastole , Female , Follow-Up Studies , Heart/physiopathology , Heart Failure/epidemiology , Humans , Hypertension/physiopathology , Male , Middle Aged , Myocardial Infarction/epidemiology , Percutaneous Coronary Intervention
AIMS: Prolonged Tpeak-Tend interval has been shown to be markers of arrhythmogenesis in various cardiac disorders. However, its dynamicity is one of the obstacles to predict fatal ventricular arrhythmia. This study investigated whether Tpeak-Tend interval during therapeutic hypothermia (TH) is associated with ventricular fibrillation (VF) inducibility and clinical arrhythmia in subjects with aborted arrhythmic sudden cardiac death (SCD). METHODS AND RESULTS: The study group included 31 patients (24 males, age 39.1 ± 17.6 years) presenting with arrhythmic SCD in whom Tpeak-Tend interval and J-wave amplitude were measured in electrocardiogram (ECG) of the earliest medical contact and during TH; these patients underwent programmed ventricular stimulation. The summation of J-wave amplitude and QTc interval increased during TH. However, it was not associated with VF inducibility. Patients with inducible VF showed a small Tpeak-Tend interval dispersion in the baseline 12-lead ECG (68.8 ± 24.7 vs. 94.0 ± 55.6 ms, P = 0.044) and a marked increase of the dispersion during the TH (36.2 ± 51.2 vs. -6.1 ± 45.5 ms, P = 0.039). Twenty-four patients underwent implantable cardioverter defibrillator (ICD) implantation. Among them, the patients with long QTc, Tpeak-Tend, and precordial Tpeak-Tend during the TH developed VF more frequently (QTc, 511.9 ± 53.71 ms vs. 566.5 ± 56.08 ms, P = 0.038; Tpeak-Tend interval, 145.6 ± 38.4 ms vs. 185.7 ± 49.95 ms, P = 0.048; precordial Tpeak-Tend interval, 139.3 ± 35.11 ms vs. 185.7 ± 49.95 ms, P = 0.018). The initial VF inducibility was not related with the VF development in follow-up. CONCLUSION: In patients with aborted arrhythmic SCD, long Tpeak-Tend interval and QTc interval during TH could predict VF development in their follow-up.
Arrhythmias, Cardiac/therapy , Death, Sudden, Cardiac/prevention & control , Electrocardiography , Hypothermia, Induced , Tachycardia, Ventricular/diagnosis , Ventricular Fibrillation/diagnosis , Action Potentials , Adult , Arrhythmias, Cardiac/complications , Arrhythmias, Cardiac/diagnosis , Arrhythmias, Cardiac/physiopathology , Death, Sudden, Cardiac/etiology , Defibrillators, Implantable , Electric Countershock/instrumentation , Electrophysiologic Techniques, Cardiac , Female , Heart Rate , Humans , Hypothermia, Induced/adverse effects , Male , Middle Aged , Predictive Value of Tests , Risk Factors , Signal Processing, Computer-Assisted , Tachycardia, Ventricular/etiology , Tachycardia, Ventricular/physiopathology , Tachycardia, Ventricular/therapy , Time Factors , Treatment Outcome , Ventricular Fibrillation/etiology , Ventricular Fibrillation/physiopathology , Ventricular Fibrillation/therapy , Young Adult
INTRODUCTION: Effects of cardiac resynchronization therapy (CRT) on arrhythmogenicity and sudden death have not been fully ascertained. CRT has been shown to increase transmural dispersion of repolarization (TDR) immediately on implantation, which may favorably remodel on long-term follow-up. However, such a hypothesis has not been prospectively evaluated. METHODS AND RESULTS: We included 35 consecutive patients who underwent CRT implantation between September 2013 and August 2014 (mean age 56.8 ± 11.09 years; 71.43% males). QT and Tpeak-Tend (Tp-e) intervals were measured during endocardial (RVendoP), epicardial (LVepiP), and biventricular pacing (BiVP) at CRT implantation and 1-year follow-up. Compared to RVendoP (130.41 ± 16.75 ms), Tp-e was significantly prolonged during BiVP (142.06 ± 21.98 ms; P < 0.001) and LVepiP (183.45 ± 27.87 ms; P < 0.001) at baseline. There was a significant decrease in Tp-e during BiVP on follow-up (117.93 ± 15.03 ms; P < 0.001). High responders had significantly lower Tp-e at 1 year compared to low responders (113.16 ± 14.3 ms vs 129.59 ± 9.75 ms, P = 0.004). Tp-e at 1 year had strong negative correlation with reduction in LV end-systolic volumes (r = - 0.51; P = 0.003). Seven patients with sustained ventricular arrhythmias during follow-up had significantly longer baseline Tp-e compared to those without arrhythmias (158.19 ± 17.59 ms vs 139.72 ± 20.94 ms, P = 0.043). A baseline Tp-e value of ≥ 148 ms had a specificity of 75% and sensitivity of 71% to predict ventricular arrhythmias. CONCLUSIONS: Baseline TDR is greater during BiVP and LV epiP compared with RVendoP in patients with heart failure. However, BiVP causes a significant reduction in TDR reflective of reverse electrical remodeling on long-term follow-up.
Cardiac Resynchronization Therapy , Heart Failure/physiopathology , Heart Failure/therapy , Ventricular Remodeling/physiology , Electrocardiography , Female , Humans , India , Male , Middle Aged , Prospective Studies , Treatment Outcome
BACKGROUND: The aim of the study was to differentiate the effect of dispersion of repolarization (DOR) and action potential duration (APD) on T-wave parameters being considered as indices of DOR, namely, Tpeak-Tend interval, T-wave amplitude and T-wave area. METHODS: T-wave was simulated in a wide physiological range of DOR and APD using a realistic rabbit model based on experimental data. A simplified mathematical formulation of T-wave formation was conducted. RESULTS: Both the simulations and the mathematical formulation showed that Tpeak-Tend interval and T-wave area are linearly proportional to DOR irrespectively of APD range, while T-wave amplitude is non-linearly proportional to DOR and inversely proportional to the minimal repolarization time, or minimal APD value. CONCLUSION: Tpeak-Tend interval and T-wave area are the most accurate DOR indices independent of APD. T-wave amplitude can be considered as an index of DOR when the level of APD is taken into account.
Action Potentials/physiology , Electrocardiography , Heart Conduction System/physiology , Animals , Body Surface Potential Mapping , Models, Cardiovascular , Models, Statistical , Rabbits
Objective To analyze the changes of Tpeak-Tend interval (Tp-Te) in patients with type 2 diabetes mellitus (T2DM),and to explore the relationship between the changes of Tp-Te and ventricular arrhythmias. Methods A total of 112 patients with T2DM were selected from the Department of endocrinology of our hospital from June 2014 to May 2016 (T2DM group),and 65 subjects underwent healthy physical examination in our hospital were selected as the normal control group (NC group) during the same period.The general data,fasting plasma glucose (FPG),glycosylated hemoglobin (HbA1c),Tp-Te,Tp-Te dispersion (Tp-Ted) were compared between the two groups.The changes of Tp-Te in patients with or without ventricular arrhythmia in T2DM group were also analyzed. Results The FPG,HbA1c,LDL-C,TC and heart rate were significantly higher in T2DM group than in the NC group (P<0.05).Compared with the control group,V5 lead Tp-Te and Tp-Ted in T2DM group was significantly prolonged (P<0.05).IN T2DM group,V5 lead Tp-Te and Tp-Ted were significantly longer in patients with ventricular arrhythmias than in patients without ventricular arrhythmia (P<0.05).Multiple logistic regression analysis showed that the increase of HbA1c and FPG were independent risk factors for prolonged Tp-Ted,and Tp-Ted was an independent risk factor for ventricular arrhythmia. Conclusion Patients with T2DM are more likely to have prolonged Tp-Ted.The prolonged Tp-Te and Tp-Ted could increase the incidence of ventricular arrhythmias.
