Influence of gender and types of sports training on QT variables in young elite athletes

Athlete's ECG Made Easy: A Practical Guide to Surviving Everyday Clinical Practice

Electrocardiogram modifications in athletes are common and usually reflect structural and electrical heart adaptations to regular physical training, known as the athlete's heart. However, these electrical modifications sometimes overlap with electrocardiogram findings that are characteristic of various heart diseases. A missed or incorrect diagnosis can significantly impact a young athlete's life and potentially have fatal consequences during exercise, such as sudden cardiac death, which is the leading cause of death in athletes. Therefore, it is crucial to correctly distinguish between expected exercise-related electrocardiogram changes in an athlete and several electrocardiogram abnormalities that may indicate underlying heart disease. This review aims to serve as a practical guide for cardiologists and sports clinicians, helping to define normal and physiology-induced electrocardiogram findings from those borderlines or pathological, and indicating when further investigations are necessary. Therefore, the possible athlete's electrocardiogram findings, including rhythm or myocardial adaptation, will be analyzed here, focusing mainly on the differentiation from pathological findings.

Left Ventricular Geometric Pattern Impacts QT Dispersion in Males Athletes and Sedentary Men

AIM

To (1) compare QT dispersion (QTd) and echocardiographic features between athletes with concentric left ventricular (LV) hypertrophy, athletes with eccentric LV hypertrophy, and sedentary controls with a normal LV geometric pattern and (2) quantify associations between QTd and echocardiographic features within these groups.

METHODS

Male athletes competing in different sports and sedentary men were stratified into groups according to their LV geometric pattern. These groups included eccentric LV hypertrophy (LV index > 115 g/m2, relative wall thickness [RWT] < 0.42) consisting of 38 athletes, concentric LV hypertrophy (LV index > 115 g/m2, RWT > 0.42) consisting of 40 athletes, and normal LV geometric pattern (LV index < 115 g/m2, RWT < 0.42) consisting of 40 sedentary controls. Following a cross-sectional design, participants underwent electrocardiographic (ECG) and echocardiographic screening. Data were compared between groups using one-way analyses of variance with Bonferroni post hoc tests. Associations between corrected QTd and echocardiographic variables were quantified using Pearson correlations.

RESULTS

Alongside structural disparities between groups, corrected QTd was significantly (p < 0.001) lower in athletes with eccentric LV hypertrophy compared to athletes with concentric LV hypertrophy and sedentary controls. Significant, moderate-to-very-large correlations were found between corrected QTd and interventricular septal wall thickness in athletes with concentric (r = 0.416, p = 0.008) or eccentric LV hypertrophy (r = 0.734, p < 0.001), and sedentary controls (r = 0.464, p = 0.003).

CONCLUSION

The provided comparative and relationship data may inform the development of more precise approaches for ECG and echocardiographic screening in athletes, particularly in those with concentric LV hypertrophy who may be at greater risk for developing prolonged QTd.

Sport-related differences in QT dispersion and echocardiographic parameters in male athletes

The aim of this study was to compare QT dispersion (QTd) and echocardiographic parameters in male athletes competing across different sports (long-distance running, volleyball, football, powerlifting, and bodybuilding) and a control population. Significant moderate-strong differences (p < 0.001, [Formula: see text] = 0.52-0.71) were found in corrected QTd, intraventricular septal wall thickness (ISWT), posterior wall thickness (PWT), relative wall thickness (RWT) and LV (left ventricular) index between groups. Corrected QTd, ISWT, PWT, and RWT were significantly (p < 0.001) higher in powerlifters and bodybuilders compared to other athlete groups and controls. While all athlete groups displayed a significantly higher LV index (p < 0.05) compared to controls, corrected QTd was significantly lower (p < 0.001) only in long-distance runners, volleyball athletes, and football athletes compared to controls. Normal or eccentric LV hypertrophy (LVH) was observed in most long-distance runners (58% and 33%), volleyball athletes (50% and 50%), and football athletes (56% and 41%). In contrast, concentric LVH was observed in most powerlifters (58%) and bodybuilders (54%). Advanced LVH, predominantly concentric in nature, appears to be accompanied with increased QTd in powerlifters and bodybuilders. On the other hand, runners, volleyball athletes, and football athletes experienced LVH toward the upper threshold of the normal reference range alongside reduced QTd compared to other groups.

Does obesity influence ventricular repolarisation in children?

OBJECTIVE

Ventricular repolarisation changes may lead to sudden cardiac death in obese individuals. We aimed to investigate the relationship between ventricular repolarisation changes, echocardiographic parameters, anthropometric measures, and metabolic syndrome laboratory parameters in obese children.

METHODS

The study involved 81 obese and 82 normal-weight healthy children with a mean age of 12.3 ± 2.7 years. Anthropometric measurements of participants were evaluated according to nomograms. Obese patients were subdivided into two groups; metabolic syndrome and non-metabolic syndrome obese. Fasting plasma glucose, fasting insulin, and lipid profile were measured. QT/QTc interval, QT/QTc dispersions were measured, and left ventricular systolic and diastolic measurements were performed.

RESULTS

Body weight, body mass index, relative body mass index, waist/hip circumference ratio, and systolic and diastolic blood pressures were significantly higher in obese children. QT and QTc dispersions were significantly higher in obese children and also obese children with metabolic syndrome had significantly higher QT and QTc dispersions compared to non-metabolic syndrome obese children (p < 0.001) and normal-weight healthy children (p < 0.001). Waist/hip circumference ratio, body mass index, and relative body mass index were the most important determinant of QT and QTc dispersions. Left ventricular wall thickness (left ventricular posterior wall thickness at end-diastole, left ventricular posterior wall thickness at end-systole, interventricular septal thickness at end-diastole) and left ventricular mass index were significantly higher and ejection fraction was lower in obese children. Left ventricular mass index and interventricular septal thickness at end-diastole were positively correlated with QT and QTc dispersions.

CONCLUSIONS

Our study demonstrated that QT/ QTc interval prolongation and increase in QT and QTc dispersion on electrocardiogram may be found at an early age in obese children.

Elevated LV Mass and LV Mass Index Sign on the Athlete's ECG: Athletes' Hearts are Prone to Ventricular Arrhythmia

OBJECTIVES

Intense exercise elevates all heart chambers' dimensions, left ventricular mass (LV mass), and left ventricular mass index (LV mass index). The relationship between increased ventricular arrhythmias and sudden cardiac death with LV dilatation and elevated LV mass has been previously demonstrated. We investigated whether sports-related LV dilatation and elevated LV mass and LV mass index cause an increase in ventricular repolarization heterogeneity.

PATIENTS AND METHODS

This prospective observational study recruited 565 participants. There were 226 (female: 28) athletes and 339 (female: 45) healthy controls between 17 and 42 years of age. They were evaluated using 12-lead-electrocardiography and transthoracic echocardiography. Electrocardiograms were obtained at a rate of 50 mm/s and an amplitude of 10 mV, including at least 3 QRS complexes for each derivation. They were taken with 12 standard deviations. Transmural dispersion of repolarization indexes (TDR) (Tp-Te interval, Tp-Te/QT ratio and Tp-Te/QTc ratio, Tp-Te(d)) were measured from precordial derivations. Measurements weretakenwith a program which was generated with MATLAB codes.

RESULTS

Tp-Te interval, Tp-Te/QT ratio, Tp-Te/QTc ratio, Tp-Te(d), PW (posterior wall thickness), IVS (interventricular septal thickness), LVEDD (left ventricular end-diastolic diameter), LV mass (left ventricular mass), and LV mass index (left ventricular mass index) for the athlete group were significantly higher than for the control group. Correlation analyses revealed that TDR indexes significantly correlated with PW, IVS, LVEDD, LV mass, and LV mass index.

CONCLUSION

LV mass and LV mass index increase in well-trained athletes, and this increase leads to an increase in TDR indexes. The increased frequency of ventricular arrhythmia and sudden cardiac death may be explained with increasing ventricular repolarization heterogeneity in these individuals.

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.

Potassium Channel Remodeling in Heart Disease

Heart disease produces substantial remodeling of K(+) channels that in general promotes arrhythmia occurrence. In the case of ventricular arrhythmias, K(+) channel remodeling contributes to the arrhythmic risk and increases vulnerability to torsades de pointes with K(+) channel inhibiting drugs. Atrial K(+) channel remodeling caused by atrial fibrillation promotes arrhythmia stability and presents opportunities for the development of new drugs targeting atrial inward rectifier K(+) currents. A better understanding of K(+) channel remodeling will help clinicians to appreciate arrhythmia mechanisms and determinants in a variety of clinical situations and to better manage arrhythmia therapy in patients with heart disease.

Heart Rate-Corrected QT and JT Intervals in Electrocardiograms in Physically Fit Students and Student Athletes

In literature, data on the prevalence of prolonged and shortened corrected QT (QTc) have shown considerable variability. The aim of the study was to compare QTc and JTc intervals of competitive student athletes and noncompetitive sport participants to QTc cutoff points used in athletes. A group of 485 physically fit candidates for the study of kinesiology (139 female and 346 male candidates) aged 18-20 participated in the study. Basic anthropometry, field fitness test, cardiovascular, electrocardiograms measurements, and blood sampling for lipid profile were conducted. The prolonged QTc according to European Society of Cardiology criteria was found in 2.9% of female and 4.3% of male students. When the "Seattle criteria" were used, the proportion of prolonged QTc was 1.44% in female and 0.29% in male students. The shortened QTc according to the Seattle cutoff points was presented in 0.7% of female and 2.0% of male students. The JTc over 400 ms was found in 0.72% of female and 0.29% of male students. The JTc shorter than 320 ms was presented in 0.7% of female and 1.1% of male students. No significant differences were found between students involved in competitive sport and those involved in recreational sporting activities. Female students had lower body mass index and blood pressure values, better blood lipid profile, and lower uric acid concentrations. In conclusion, the Seattle criteria markedly decreased the proportion of prolonged QTc in student athletes, particularly in male students. It seems that the JTc interval could be a better parameter than the QTc interval for the estimation of specific repolarization time in physically fit university students.

Effect of Isometric Exercise on QTc Interval

INTRODUCTION

The QTc interval is affected by heart rate, autonomic nervous system and diseases like diabetes. However, the affect of exercise which alters autonomic nervous system activity, on QTc is not clear. On the other hand, the incidence of sudden cardiac death increases many fold post exercise. These events may be better explained by studying the effect of exercise on QTc.

AIM

This study was designed with an aim to record the QTc interval changes in response to isometric exercise in a group of normal individuals with or without parental history of diabetes mellitus. Also the QTc duration was correlated with the LF-HF ratio.

MATERIALS AND METHODS

Twenty nine, healthy medical students were subjected to isometric hand grip test for 5min. ECG was recorded pre-exercise and at various time intervals post-exercise.

STATISTICAL ANALYSIS

All data are expressed in mean ± SD. Intra group comparison was done using paired t-test and unpaired t-test was used for comparison among group I and group II subjects, and among males and females.

RESULT

The difference in the pre and post exercise QTc values both within and between groups was statistically significant with group I subjects recording lower values. The post exercise LF: HF values were significantly increased when compared to pre exercise values in both the groups. There was no correlation between LF: HF and QTc.

CONCLUSION

A longer than normal QTc interval predisposes to arrhythmia. Exercise brings about detectable changes in the QTc interval after a period of isometric exercise in normal individuals which in high risk individuals may predispose to sudden cardiac death. In addition women may be more susceptible to post-exercise arrhythmia owing to a longer QTc even at rest.