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

Predicting Long-Term Ventricular Arrhythmia Risk in Children with Acute Lymphoblastic Leukemia Using Normal Values of Ventricular Repolarization Markers Established from Japanese Cohort Study

BACKGROUND

Cardiac complications due to anthracycline treatment may become evident several years after chemotherapy and are recognized as a serious cause of morbidity and mortality in cancer patients or childhood cancer survivors.

OBJECTIVES

We analyzed ventricular repolarization parameters in electrocardiography for pediatric acute lymphoblastic leukemia patients during chemotherapy and in long-term follow-up. To establish the reference values of ventricular repolarization parameters in children, we retrospectively summarized the Tpe interval, QT interval, QTc interval, and Tpe/QT ratio in healthy Japanese children.

METHODS

Electrocardiography data recorded from students in 1st and 7th grades were randomly selected from a database maintained by the school-based screening system in the Oita city cohort, Japan. Subsequently, chronological data of the Tpe/QT ratio in 17 pediatric patients with acute lymphoblastic leukemia were analyzed over time.

RESULTS

The mean ± standard deviation of the Tpe interval in 1st and 7th graders was 70 ± 7 and 78 ± 17 ms, respectively, while the mean ± standard deviation of the Tpe/QT ratio was 0.21 ± 0.02 and 0.22 ± 0.02 ms, respectively. During the intensive phase of treatment, the Tpe/QT ratios of 3 high-risk patients among the 17 patients with acute lymphoblastic leukemia exceeded the upper limit.

CONCLUSION

The Tpe/QT ratio has a potential clinical application in predicting the risk of long-term ventricular arrhythmia of cancer patients or childhood cancer survivors from childhood to adulthood.

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.

Age-Related Electrocardiographic Characteristics of Male Junior Soccer Athletes

Introduction

Very limited data exist on normal age-related ECG variations in adolescents and no data have been published regarding the ECG anomalies induced by intensive training, which are relevant in pre-participation screening for sudden cardiac death prevention in the adolescent athletic population. The purpose of this study was to establish normal age-related electrocardiographic measurements (P wave duration, PR interval, QRS duration, QT, and QTc interval) grouped according to 2-year age intervals.

Methods

A total of 2,151 consecutive healthy adolescent Soccer athletes (trained for a mean of 7.2 ± 1.1 h per week, 100% male Caucasians, mean age 12.4 ± 1.4 years, range 7–18) underwent pre-participation screening, which included ECG and transthoracic echocardiography in a single referral center.

Results

Their heart rate progressively slowed as age increased (p < 0.001, ranging from 80.8 ± 13.2 to 59.5 ± 10.2 bpm), as expected. The P wave, PR interval, and QRS duration significantly increased in older age classes (p = 0.019, p = 0.001, and p < 0.001, respectively), and after Bonferroni's correction, the difference remained significant in all age classes for QRS duration. The QTc interval diminished progressively with increasing age (p = 0.003) while the QT interval increased progressively (p < 0.001).

Conclusions

Significant variations in the normal ECG characteristics of young athletes exist between different age groups related to increasing age and training burden, thus, age-specific reference values could be adopted, as already done for echocardiographic measurements, and may help to further discriminate potentially pathologic conditions.

Ventricular Repolarization Parameters and Coronary Involvement in Kawasaki Disease

OBJECTIVES

To evaluate electrocardiogram markers to predict coronary involvement in patients with Kawasaki disease by assessing measures of ventricular repolarization parameters on the 12-lead electrocardiogram.

STUDY DESIGN

This cross-sectional study included 180 Spanish and Japanese patients ≤14 years of age with Kawasaki disease, with or without coronary involvement, from 2011 to 2016. We manually measured the Tp-Te/QT ratio and QTc interval (with Bazett's formula) in 12-lead electrocardiogram in the acute and recovery period and explored their potential association with coronary involvement.

RESULTS

No association was found between Tp-Te/QT ratio obtained manually in V5 and V6 leads and coronary involvement in the acute (V5:0.25 [IQR, 0.21-0.27] vs 0.25 [IQR, 0.20-0.27], P = .80; V6:0.24 [IQR, 0.21-0.27] vs 0.25 [IQR, 0.20-0.27], P = .86) or the recovery (V5: 0.23 [IQR, 0.20-0.25] vs 0.23 [IQR, 0.19-0.25], P = .68; V6: 0.23 [IQR, 0.20-0.25] vs 0.23 [IQR, 0.17-0.25], P = .50) period. By contrast, QTc in V5 and V6 was significantly lower in patients with Kawasaki disease and coronary involvement in the acute period (V5: 378 ms [IQR, 364-395 ms] vs 390 ms [IQR, 371-411 ms], P = .04; V6: 377 ms [IQR, 364-392 ms] vs 390 ms [IQR, 371-410 ms], P = .01). A QTc interval of <385 ms in lead V6 was associated with a 2.5-fold increased risk of coronary involvement (OR, 2.5; 95% CI, 1.2-5.3; P = .02).

CONCLUSIONS

Manually measured QTc interval may be a marker of coronary disease in the acute period of Kawasaki disease.

Association between Tpeak-Tend/QT and major adverse cardiovascular events in patients with Takotsubo syndrome

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.

Tpeak-Tend, Tpeak-Tend dispersion and Tpeak-Tend/QT in children and its relationship with clinical variables

Aim

To characterize the Tpeak-Tend, the Tpeak-Tend dispersion and Tpeak-Tend/QT in children and its relationship with clinical variables.

Methods

Cross-sectional study in 126 children between 9 and 12 years of the Camilo Cienfuegos School in Santa Clara, Cuba. Clinical and anthropometric variables were obtained to determine their relationship with electrocardiographic parameters: Tpeak-Tend V5, Tpeak-Tend dispersion and Tpeak-Tend/QT ratio V5. In addition, laboratory tests were conducted.

Results

Age and systolic blood pressure are associated with an increased probability of having values of Tpeak-Tend/QT V5 ≥75 percentile for both sexes (OR: 1.72, CI 95%: 1.02-2.91; p= 0.043), (OR: 1.08, CI 95%: 1.01-1.16; p= 0.017) respectively. The body mass index and systolic blood pressure are linearly and significantly correlated with the Tpeak-Tend/QT V5 (r= 0.224; p= 0.012) and (r= 0.220; p= 0.014) respectively.

Conclusions

The age of the patients and the systolic blood pressure figures are factors that increase the probability of having values of the Tpeak-Tend/QT V5 ≥75 percentile. There was a significant linear correlation between the Tpeak-Tend/QT V5 with the body mass index and the systolic blood pressure.

Assessment of increased risk of arrhythmia in advanced age pregnancies

Background and Objective:

Cardiovascular deaths usually occur in older pregnancies and arrhythmia is the third most common cause. Our study aimed to determine whether the risk of arrhythmia increases in pregnancy with advanced age.

Methods:

In total, 280 pregnant women, of whom 98 were of advanced age and 182 were under 35 years of age were included in the study. The risk of arrhythmia was evaluated by calculating the electrocardiographic P-wave duration, QT interval, T peak-to-end interval, and the Tp-e/QT ratio.

Results:

Although there were no differences in the Tp-e interval and Tp-e/QTc ratio between the groups, the maximum QTc, minimum QTc, and QTc dispersion values were significantly higher in advanced-age pregnancies compared to the control group. In addition, the P dispersion was greater in advanced-age pregnancies. In correlation analysis, the increased dispersion of QTc and P were positively correlated with maternal age. Multiple linear regression analysis showed that QTc dispersion was independently associated with maternal age.

Conclusion:

Repolarization parameters increase in advanced-age pregnancies even though they remain in the normal range, which should lead to an investigation of whether this is a pathological condition.

Effect of age and gender on the QTc-interval in healthy individuals and patients with long-QT syndrome

Age- and gender-related differences in QTc-interval are most likely the result of changes in sex-specific hormones. Although the exact mechanisms and pathophysiology of sex hormones on the QTc-interval are not known, testosterone appears to shorten the QTc-interval. In females, however, there is a more complex interaction between progesterone and estrogen. In patients with an impaired repolarization, such as long-QT syndrome (LQTS), the effect of these sex hormones on the QTc-interval is more pronounced with a differing sensitivity between the LQTS genotypes.