TpTe and TpTe/QT: novel markers to predict sudden cardiac death in ESRD? / TpTe e TpTe/QT: novos marcadores para prever morte súbita cardíaca na DRT?

ABSTRACT Introduction: Reliable markers to predict sudden cardiac death (SCD) in patients with end stage renal disease (ESRD) remain elusive, but echocardiogram (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.

RESUMO Introdução: Marcadores confiáveis para predizer morte súbita cardíaca (MSC) em pacientes com doença renal terminal (DRT) permanecem elusivos, mas os parâmetros do ecocardiograma (ECG) podem ajudar a estratificar os pacientes. Devido a seus papéis como marcadores para a dispersão miocárdica, especialmente em populações de alto risco, como aquelas com síndrome de Brugada, nós hipotetizamos que o intervalo pico da onda T ao final da onda T (TpTe) e TpTe/QT são fatores de risco independentes para MSC na DRT. Métodos: Revisão retrospectiva do prontuário foi realizada em uma coorte de pacientes com DRT iniciando a hemodiálise. Os pacientes eram veteranos de guerra americanos que utilizavam os centros médicos do Veterans Affairs para atendimento médico. A idade média de todos os participantes foi de 66 anos e a maioria era do sexo masculino, consistente com uma população veterana dos EUA. ECGs que foram realizados dentro de 18 meses após o início da diálise, e foram avaliados manualmente para TpTe e TpTe/QT. Os desfechos primários foram MSC e mortalidade por todas as causas, e estes foram avaliados até 5 anos após o início da diálise. Resultados: Após o critério de exclusão, foram identificados 205 pacientes, dos quais 94 com TpTe prolongado e 61 com intervalo TpTe/QT prolongado (não mutuamente exclusivo). A mortalidade geral foi de 70,2% em 5 anos e a MSC foi de 15,2%. Nenhuma diferença significativa foi observada nos desfechos primários ao se avaliar o TpTe (MSC: prolongado 16,0% versus normal 14,4%, p = 0,73; mortalidade por todas as causas: prolongado 55,3% vs. normal 47,7%, p = 0,43). Da mesma forma, nenhuma diferença significativa foi encontrada para TpTe/QT (MSC: prolongado 15,4% vs. normal 15,0%, p = 0,51; mortalidade por todas as causas: prolongado 80,7% vs. normal 66,7%, p = 0,39). Conclusões: Em pacientes com insuficiência renal terminal em hemodiálise, TpTe ou TpTe/QT prolongados não foram associados a um aumento significativo da morte súbita ou mortalidade por todas as causas.

Effect of Cardiac Resynchronization Therapy in Patients With Dispersion of Re-polarization and Ventricular Arrhythmia / 中国循环杂志

Objective: To explore the effects of cardiac resynchronization therapy (CRT) in patients with dispersion of re-polarization and ventricular arrhythmia. Methods: A total of 86 consecutive patents with CRT implantation were enrolled. According to weather absolute value of LVEF increased≥10% from baseline at 6 months after CRT implantation, the patients were divided into 2 groups: Response group and Non-response group,n=43 in each group. Dispersion of re-polarization indexes as QRS duration, QTc interval, TpTe interval and the events of ventricular arrhythmia were compared between 2 groups at different time points after CRT. Results:①In Response group, compared with pre-operation, QRS duration and TpTe interval were shorter at 1 year and within 24h after CRT implantation, allP0.05.②During 1 year after CRT implantation, the incidences of PVCs and PVC runs in Response group were much less than those in Non-response group, for lgPVCs: (1.78 ± 0.77) vs (2.73 ± 0.61), for lgPVC runs: (0.64 ± 0.48) vs (1.98 ± 0.72),P Conclusion: CRT ventricular reverse remodeling may reduce dispersion of re-polarization and the risk of ventricular arrhythmia, therefore improve the prognosis in relevant patients; TpTe interval within 24h after CRT had the predictive value for ventricular arrhythmia.

Change in ventricular repolarization among healthy young males exposed to high altitude / 军事医学

Objective To investigate the change in ventricular repolarization at different altitudes and time courses among healthy young males .Methods A total of 143 healthy young men living on the plains were randomly selected as subjects.Their change in relative parameters of ventricular repolarization was measured by the same person at 500 m above sea level,24 hours their ascent to the plateau at an altitude of 3700 m was,after one week′s acclimatization on the 4400 m plateau and after 50 days acclimatization on the 4400 m plateau.Results Compared with 500 m,at 3700 m above sea level in 24 hours and after one week′s acclimatization on the 4400 m plateau,the heart rate(HR),systolic blood pressure(SBP), diastolic blood pressure(DBP), heart rate-corrected-QT (QTc)interval and heart rate-corrected T-peak to T-end (TpTec) on V3 lead were significantly increased(P0.05) after 50 days acclimatization on the 4400 m plateau.Conclusion The ventricular repolarization duration of these young healthy men was significantly increased when they rapidly ascentded to high altitude .With prolonging residence at high alti-tude,the ventricular repolarization duration gradually returned to the level on the plains ,suggesting that the the ventricular repolarization duration will be restored to its level on the sea level by the adaptation and adjustment mechanism of the body .

The Correlation of T peak-T end Interval and Ventricular Arrhythmia in Patients with Acute Myocardial Infarction / 天津医药

Objective To investigate the relationship of T peak-T end (Tp-Te) interval and Tp-Te interval disper-sion (Tp-Ted) in different periods of myocardial ischemia in patients with acute myocardial infarction (AMI), and to assess the clinical significance of Tp-Te and Tp-Ted for prediction of the ventricular arrhythmia (VA). Methods A total of 80 pa-tients with AMI were enrolled in the study. The sizes and changes of Tp-Te and Tp-Ted were observed during the acute phase and recovery phase in patients. The differences of Tp-Te and Tp-Ted were compared between ventricular tachycardia group (A group), ventricular premature beats group (B group) and non- ventricular arrhythmia group (C group). Results The values of Tp-Te and Tp-Ted were obviously longer in acute period [(125.22±17.70) ms and (54.76±13.26) ms] than those in recovery period[ (113.84±17.37) ms and (42.06±13.95)ms] (P<0.01). The values of Tp-Te and Tp-Ted were signifi-cantly longer in A group[ (134.82±19.56) ms and (62.00±15.19) ms] than those in B [(122.94±15.09) ms and (54.09±10.56) ms ]and C group [(110.09±15.21) ms and (45.27±9.85) ms]. The values were higher in B group than those of C group. Con-clusion The Tp-Te interval and Tp-Ted prolongated in acute phase than those of recovery phase in patients with AMI. Tp-Te interval and Tp-Ted can be used as an important index to predict VA in patients with AMI.

The Relativity between Tp-Te interval,Tp-Te/QT Ratio with Heart Rate in Normal Individuals / 医学研究杂志

Objective To compare the relativity between Tp-Te interval,Tp-Te /QT ratio with heart rate(HR)and explore their clinical significance retrospectively.Methods 200 normal individuals' ECG were randomly selected and the Tp-Te interval and Tp-Te/QT ratio were measured in precordial lead V6 retrospectively.The relativity between Tp-Te interval and Heart Rate,Tp-Te/QT ratio and Heart Rate were calculated retrospectively.Results The Tp-Te interval was about(83.17?12.64)ms in precordial lead V6 of normal individuals.The Tp-Te interval decreased linearly with the increase in HR with the range of Tp-Te interval being 56 to 114 milliseconds(Pearson's correlation coefficient r was-0.239,P=0.007 0.01).Conclusion There is an inverse correlation between Tp-Te interva and HR while no correlation between Tp-Te/QT ratio and HR.