Noninvasive cardiac screening in young athletes with ventricular arrhythmias

Clinical Considerations for Competitive Sports Participation for Athletes With Cardiovascular Abnormalities: A Scientific Statement From the American Heart Association and American College of Cardiology

This American Heart Association/American College of Cardiology scientific statement on clinical considerations for competitive sports participation for athletes with cardiovascular abnormalities or diseases is organized into 11 distinct sections focused on sports-specific topics or disease processes that are relevant when considering the potential risks of adverse cardiovascular events, including sudden cardiac arrest, during competitive sports participation. Task forces comprising international experts in sports cardiology and the respective topics covered were assigned to each section and prepared specific clinical considerations tables for practitioners to reference. Comprehensive literature review and an emphasis on shared decision-making were integral in the writing of all clinical considerations presented.

Clinical Considerations for Competitive Sports Participation for Athletes With Cardiovascular Abnormalities: A Scientific Statement From the American Heart Association and American College of Cardiology

This American Heart Association/American College of Cardiology scientific statement on clinical considerations for competitive sports participation for athletes with cardiovascular abnormalities or diseases is organized into 11 distinct sections focused on sports-specific topics or disease processes that are relevant when considering the potential risks of adverse cardiovascular events, including sudden cardiac arrest, during competitive sports participation. Task forces comprising international experts in sports cardiology and the respective topics covered were assigned to each section and prepared specific clinical considerations tables for practitioners to reference. Comprehensive literature review and an emphasis on shared decision-making were integral in the writing of all clinical considerations presented.

Ventricular arrhythmias in association with athletic cardiac remodelling

Athletes are predisposed to atrial arrhythmias but the association between intense endurance exercise training, ventricular arrhythmias (VAs), and sudden cardiac death is less well established. Thus, it is unclear whether the 'athlete's heart' promotes specific arrhythmias or whether it represents a more general pro-arrhythmogenic phenotype. Whilst direct causality has not been established, it appears possible that repeated exposure to high-intensity endurance exercise in some athletes contributes to formation of pro-arrhythmic cardiac phenotypes that underlie VAs. Theories regarding potential mechanisms for exercise-induced VAs include repeated bouts of myocardial inflammation and stretch-induced cellular remodelling. Small animal models provide some insights, but larger animal and human data are sparse. The current clinical approach to VAs in athletes is to differentiate those with and without structural or electrical heart disease. However, if the athlete's heart involves a degree of pro-arrhythmogenic remodelling, then this may not be such a simple dichotomy. Questions are posed by athletes with VAs in combination with extreme remodelling. Some markers, such as scar on magnetic resonance imaging, may point towards a less benign phenotype but are also quite common in ostensibly healthy athletes. Other clinical and invasive electrophysiology features may be helpful in identifying the at-risk athlete. This review seeks to discuss the association between athletic training and VAs. We will discuss the potential mechanisms, clinical significance, and approach to the management of athletes with VAs.

Brazilian Guideline for Exercise Testing in Children and Adolescents - 2024

CLASSES OF RECOMMENDATION

LEVELS OF EVIDENCE

Classification of Premature Ventricular Contractions in Athletes During Routine Preparticipation Exams

BACKGROUND

Large-scale data on incidental premature ventricular contraction (PVC) prevalence and morphologies have been lacking, leaving many providers without guidance on further cardiac testing for patients with incidental PVCs on ECG. Athletes offer an intriguing cohort to understand the clinical significance, prevalence, and common morphologies of incidental PVCs because they often undergo ECG screening during preparticipation exams.

METHODS

Digital ECGs were obtained from 10 728 screened athletes aged 14 to 35 years during mass screenings in schools and professional sports teams between 2014 and 2021. A retrospective analysis of ECGs with PVCs was performed using the simultaneous display of frontal (limb) and horizontal (precordial) plane leads. PVCs were coded for morphology and categorized as benign or nonbenign using recommended criteria.

RESULTS

Twenty-six athletes (0.24%) were found to have at least 1 PVC. Among these, 50% were female, 65% were White, 8% were Asian, 4% were Hispanic, and 23% were Black. Nineteen of the 26 (73%) ECGs had PVCs with a left bundle branch block pattern compared with 7 (27%) with a right bundle branch block pattern. Twenty-four ECGs (96%) had PVCs with benign patterns, including 18 with right ventricular outflow tract, 5 with left anterior fascicle, and 2 with left posterior fascicle morphology.

CONCLUSIONS

There is a low prevalence of PVCs on routine ECG screening of young athletes, and most PVCs are of benign morphology in this population. This study highlights the value of using digital ECG recorders with simultaneous lead display to guide decision-making about further cardiac testing and referrals in young athletes with PVCs. Using our results and review of the literature, we propose methods and algorithms of PVC evaluation on screening ECGs to help guide many providers with risk stratification and decision-making about further cardiac testing and electrophysiology referrals in young athletes with PVCs.

Idiopathic Premature Ventricular Contraction Catheter Ablation, Sedentary Population vs. Athlete's Populations: Outcomes and Resumption of Sports Activity

There are no investigations about the outcomes of idiopathic PVC catheter ablation (CA) in athletes compared to the sedentary population. We conducted a prospective single-centre observational study. The primary and secondary procedural outcomes were the post-ablation reduction of premature ventricular contractions (PVCs) in an athletes vs. non-athletes group and in agonist vs. leisure-time athletes. The third was the evaluation of the resumption of physical activity and the improvement of symptoms in agonist and leisure-time athletes. From January 2020 to October 2022 we enrolled 79 patients with RVOT/LVOT/fascicular PVC presumed origin. The median percentage of decrease between the pre-procedure and post-procedure Holter monitoring in the non-athletes group was 96 (IQR 68-98) and 98 in the athletes group (IQR 92-99) (p = 0.08). Considering the athletes, the median percentage of decrease in the number of PVCs was 98 (IQR 93-99) and 98 (IQR 87-99), respectively, in leisure-time and agonistic athletes (p = 0.42). Sixteen (70%) leisure time and seventeen (90%) agonist athletes (p = 0.24) have resumed physical activity 3 months after PVC CA; among agonistic athletes, 59% have resumed competitive physical activity. Many leisure-time (88%) and agonist (70%) athletes experienced an improvement in symptoms after ablation. PVC CA was effective and safe in both groups, reducing symptoms and allowing a quick and safe return to sports activities in athletes.

Ventricular arrhythmias recorded on 12-lead ambulatory electrocardiogram monitoring in healthy volunteer athletes and controls: what is common and what is not

AIMS

Premature ventricular beats (PVBs) in athletes are often benign, but sometimes they may be a sign of an underlying disease. We evaluated the prevalence, burden, and morphology of PVBs in healthy voluntary athletes and controls with the main purpose of defining if certain PVB patterns are 'common' and 'training related' and, as such, are more likely benign.

METHODS AND RESULTS

We studied 433 healthy competitive athletes [median age 27 (18-43) years, 74% males] and 261 age- and sex-matched sedentary subjects who volunteered to undergo 12-lead 24 h ambulatory electrocardiogram (ECG) monitoring (24H ECG), with a training session in athletes. Ventricular arrhythmias (VAs) were evaluated in terms of their number, complexity [i.e. couplet, triplet, or non-sustained ventricular tachycardia (NSVT)], exercise inducibility, and morphology. Eighty-six percent of athletes and controls exhibited a total of ≤10 PVBs/24 h, and >90% did not show any couplets, triplets, or runs of NSVT > 3 beats. An higher number of PVBs correlated with increasing age (P < 0.01) but not with sex and level of training. The most frequent morphologies among the 36 athletes with >50 PVBs were the infundibular (44%) and fascicular (22%) ones. In a comparison between athletes and sedentary individuals, and male and female athletes, no statistically significant differences were found in PVBs morphologies.

CONCLUSION

The prevalence and complexity of VAs at 24H ECG did not differ between athletes and sedentary controls and were not related to the type and amount of sport or sex. Age was the only variable associated with an increased PVB burden. Thus, no PVB pattern in the athlete can be considered 'common' or 'training related'.

Asymptomatic cardiac tumour with premature ventricular contraction in an athlete: case report

Cardiac fibromas are the second most common benign primary tumour of the heart in the children; the clinical features include chest pain, arrhythmia, low cardiac output due to outflow tract obstruction, and sudden cardiac death. Sports are associated with an increased risk for sudden death in athletes who are affected by cardiovascular conditions predisposing to life-threatening arrhythmias. We present a case report of 10-year-old asymptomatic boy who was referred to the paediatric cardiology department by his general practitioner for cardiac examination before participation in competitive sports. The electrocardiogram showed premature ventricular contractions originated from inferior of left ventricle. A mass was detected by 2D transthoracic echocardiography, and it was found to be compatible with fibroma on MRI. In some cases, cardiac tumours are asymptomatic as in our patient. Electrocardiogram abnormalities require detailed cardiac imaging with echocardiogram, and if necessary CT/MRI. In this article, we emphasise that detailed cardiac examination of individuals before participating in competitive sports is vital.

Role of Cardiac Magnetic Resonance Imaging in the Evaluation of Athletes with Premature Ventricular Beats

Premature ventricular beats (PVBs) in athletes are not rare. The risk of PVBs depends on the presence of an underlying pathological myocardial substrate predisposing the subject to sudden cardiac death. The standard diagnostic work-up of athletes with PVBs includes an examination of family and personal history, resting electrocardiogram (ECG), 24 h ambulatory ECG (possibly with a 12-lead configuration and including a training session), maximal exercise testing and echocardiography. Despite its fundamental role in the diagnostic assessment of athletes with PVBs, echocardiography has very limited sensitivity in detecting the presence of non-ischemic left ventricular scars, which can be revealed only through more in-depth studies, particularly with the use of contrast-enhanced cardiac magnetic resonance (CMR) imaging. The morphology, complexity and exercise inducibility of PVBs can help estimate the probability of an underlying heart disease. Based on these features, CMR imaging may be indicated even when echocardiography is normal. This review focuses on interpreting PVBs, and on the indication and role of CMR imaging in the diagnostic evaluation of athletes, with a special focus on non-ischemic left ventricular scars that are an emerging substrate of cardiac arrest during sport.

Recommendations for participation in leisure-time physical activity and competitive sports of patients with arrhythmias and potentially arrhythmogenic conditions. Part 2: ventricular arrhythmias, channelopathies, and implantable defibrillators

This paper belongs to a series of recommendation documents for participation in leisure-time physical activity and competitive sports by the European Association of Preventive Cardiology (EAPC). Together with an accompanying paper on supraventricular arrhythmias, this second text deals specifically with those participants in whom some form of ventricular rhythm disorder is documented, who are diagnosed with an inherited arrhythmogenic condition, and/or who have an implanted pacemaker or cardioverter defibrillator. A companion text on recommendations in athletes with supraventricular arrhythmias is published in the European Journal of Preventive Cardiology. Since both texts focus on arrhythmias, they are the result of a collaboration between EAPC and the European Heart Rhythm Association (EHRA). The documents provide a framework for evaluating eligibility to perform sports, based on three elements, i.e. the prognostic risk of the arrhythmias when performing sports, the symptomatic impact of arrhythmias while performing sports, and the potential progression of underlying structural problems as the result of sports.

Back somersault-induced atrioventricular nodal reentrant tachycardia - A case of a 15-year-old promising gymnast

A male 15-year-old promising gymnast suffered palpitations, which emerged only after landing a round-off back somersault. The performance induced an attack of regular narrow QRS complex tachycardia that was highly reproducible. Not a single element of the performance, but a whole sequence of round-off back somersault was required to induce the attack. An electrophysiologic study revealed an intra-nodal dual pathway causing atrioventricular nodal reentrant tachycardia (AVNRT). A complication of a tiny atrial septal defect (ASD) was incidentally detected, thus we initially suspected a causal relation of ASD as the platypnea-orthodeoxia syndrome. However, it was denied as the major mechanism of attack because of a very faint shunt flow and no-induction of hypoxemia during a round-off back somersault. The major triggering mechanisms of a whole sequence of round-off back somersaults were speculated to be related to transient atrial overload and autonomic imbalance induced by a swift postural-axial change together with an intense Valsalva maneuver with the maximal level of breath holding. The AVNRT attack was successfully treated by radiofrequency catheter ablation and has never recurred even by a whole sequence of round-off back somersaults. Currently he is a healthy and active gymnast with no symptoms. <Learning objective: The individual trigger of an atrioventricular nodal reentrant tachycardia (AVNRT) attack varies. The unique and sole trigger of the attack in the present gymnast case was a whole sequence of round-off back somersaults. A swift postural-axial change together with an intense Valsalva maneuver with the maximal level of breath holding increased the atrial overload with stretching the atrial wall, which might have induced atrial extrasystole and played a trigger role initiating the AVNRT attack.>.

Sudden Death in the Young: Information for the Primary Care Provider

There are multiple conditions that can make children prone to having a sudden cardiac arrest (SCA) or sudden cardiac death (SCD). Efforts have been made by multiple organizations to screen children for cardiac conditions, but the emphasis has been on screening before athletic competition. This article is an update of the previous American Academy of Pediatrics policy statement of 2012 that addresses prevention of SCA and SCD. This update includes a comprehensive review of conditions that should prompt more attention and cardiology evaluation. The role of the primary care provider is of paramount importance in the evaluation of children, particularly as they enter middle school or junior high. There is discussion about whether screening should find any cardiac condition or just those that are associated with SCA and SCD. This update reviews the 4 main screening questions that are recommended, not just for athletes, but for all children. There is also discussion about how to handle post-SCA and SCD situations as well as discussion about genetic testing. It is the goal of this policy statement update to provide the primary care provider more assistance in how to screen for life-threatening conditions, regardless of athletic status.

Clinical management of young competitive athletes with premature ventricular beats: A prospective cohort study

BACKGROUND

Premature ventricular beats (PVBs) are not an unusual finding and their interpretation is sometimes challenging. Unfortunately, few data on the characteristics of PVBs that correlate with the risk of an underlying heart disease are available in athletes.

OBJECTIVES

The aim of this prospective study was to investigate the diagnostic and prognostic value of PVBs characteristics in competitive athletes.

METHODS

From a cohort of 1751 athletes evaluated at our sports cardiology centre, we enrolled 112 competitive athletes <40 years of age (mean age 21 ± 10 years) and with no known heart disease referred for PVBs. All athletes underwent physical examination, ECG, 12‑lead ambulatory ECG monitoring, exercise testing, and echocardiography. Further investigations including cardiac magnetic resonance were performed for abnormal findings at first-line evaluation or for specific PVBs characteristics.

RESULTS

The majority (79%) of athletes exhibited monomorphic PVBs with a fascicular or infundibular pattern (common morphologies). A definitive diagnosis of cardiac disease was reached in 26 athletes (23% of the entire population) and correlated with uncommon PVBs morphology (p < 0.001) and arrhythmia complexity (p < 0.001). The number of PVBs/24-h was lower in athletes with cardiac disease than in those with normal heart (p < 0.05). During the follow-up a spontaneous reduction of PVBs and no adverse events were observed.

CONCLUSIONS

Infundibular and fascicular PVBs were the most common morphologies observed in athletes with ventricular arrhythmias referred for cardiological evaluation. Morphology and complexity of PVBs, but not their number, predicted the probability of an underlying disease. Athletes with PVBs and negative investigation showed a good prognosis.

Ventricular arrhythmias and risk stratification of cardiac sudden death in athletes

Sudden cardiac death (SCD) of young athletes is an unexpected and tragic event that could occur during sport activities and is frequently related to ventricular arrhythmias. Identifying athletes at risk of SCD remains a major challenge. While specific characteristics of premature ventricular contractions are considered common and benign, other "uncommon" features should require more accurate investigations, in order to determine eligibility for competitive sports. The most common type of idiopathic premature ventricular contractions originates from ventricular outflow tract and is characterized by an ECG pattern with left bundle branch block and inferior QRS axis (infundibular pattern). Another pattern associated with a good prognosis is the "fascicular" morphology, characterized by a typical right bundle branch block, superior QRS axis morphology and QRS duration <130 ms. Conversely, other morphological features (such as left bundle branch block /intermediate or superior axis or right bundle branch block/intermediate or superior axis and wide QRS) correlate to an underlying substrate. In risk stratification setting, cardiac magnetic resonance plays a key role allowing an accurate identification of myocardial tissue abnormalities, which could affect athletes' prognosis. This review focuses on characteristics of premature ventricular contractions characteristics in terms of morphology, distribution, complexity and response to exercise and describes the possible underlying myocardial substrates. This review also critically analyzes the evaluation process of athletes with premature ventricular contractions necessary for an accurate risk stratification.

How to evaluate premature ventricular beats in the athlete: critical review and proposal of a diagnostic algorithm

Although premature ventricular beats (PVBs) in young people and athletes are usually benign, they may rarely mark underlying heart disease and risk of sudden cardiac death during sport. This review addresses the prevalence, clinical meaning and diagnostic/prognostic assessment of PVBs in the athlete. The article focuses on the characteristics of PVBs, such as the morphological pattern of the ectopic QRS and the response to exercise, which accurately stratify risk. We propose an algorithm to help the sport and exercise physician manage the athlete with PVBs. We also address (1) which athletes need more indepth investigation, including cardiac MRI to exclude an underlying pathological myocardial substrate, and (2) which athletes can remain eligible to competitive sports and who needs to be excluded.

Monomorphic Ventricular Arrhythmias in Athletes

Ventricular arrhythmias are challenging to manage in athletes with concern for an elevated risk of sudden cardiac death (SCD) during sports competition. Monomorphic ventricular arrhythmias (MMVA), while often benign in athletes with a structurally normal heart, are also associated with a unique subset of idiopathic and malignant substrates that must be clearly defined. A comprehensive evaluation for structural and/or electrical heart disease is required in order to exclude cardiac conditions that increase risk of SCD with exercise, such as hypertrophic cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy. Unique issues for physicians who manage this population include navigating athletes through the decision of whether they can safely continue their chosen sport. In the absence of structural heart disease, therapies such as radiofrequency catheter ablation are very effective for certain arrhythmias and may allow for return to competitive sports participation. In this comprehensive review, we summarise the recommendations for evaluating and managing athletes with MMVA.

Assessment of premature ventricular beats in athletes

INTRODUCTION

Premature ventricular complexes (PVC) are generally considered as a benign electrocardiographic abnormality in the athletic population. However it may be indicative of underlying heart disease which may increase the risk of sudden death. This implies the need for cardiological evaluation before indicating the ability to practice competitive sports.

AIM

The aim of this study was to evaluate an athlete population with PVC and establish underlying etiologies in order to take a decision regarding practicing sports.

METHODS

This is a prospective study which included athletes examined in the Tunisian National Centre of Sports Medicine and Sports Science (TNCSM) from January 2013 to June 2015 who presented PVC on an electrocardiogram.

RESULTS

Five thousand seven hundred and ninety eight athletes were referred to the TNCSM. We identified 42 athletes having PVC with a prevalence of 1.8%. The average age of the study population was 21.6±5.99 years. 83% were men. 88% were asymptomatic. The electrocardiogram was considered normal in 62% of the athletes according to the Seattle criteria. At the Holter monitoring, the average number of PVC was 920 PVC/24hours. Thirteen athletes had doublets and 11 had triplets. One patient had polymorphic PVC and an R/T phenomenon. The transthoracic echocardiography (TTE) was normal in 71% of cases. Three athletes had hypertrophic cardiomyopathy (HCM). All patients underwent a stress test. The PVC disappeared in 12% of athletes MRI was performed in 10 athletes confirming the three cases of HCM and revealing a case of arrhythmogenic right ventricular dysplasia and a case of compression of the right ventricle by pectus exacavatum.

CONCLUSION

After this assessment, five athletes were not allowed to practice sport. This study shows the necessity of a thorough cardiological assessment of athletes with ventricular arrhythmia in order to detect underlying heart disease and prevent sudden death in this young apparently healthy population.

Premature ventricular beats in the athlete: management considerations

INTRODUCTION

Premature ventricular beats (PVBs) in competitive athletes are incidentally found during pre-participation ECG screening. Their clinical significance remains debatable with several studies suggesting they are a benign reflection of athlete's heart, and others proposing they may indicate underlying structural heart disease and heightened risk for sudden cardiac death (SCD). Areas covered: Effective management of athletes with PVBs may best be accomplished using an algorithmic approach for risk stratification with a goal of differentiating benign PVBs from those reflective of underlying cardiomyopathies. Current AHA/ACC consensus recommendations provide a platform for determining optimal medical and invasive therapeutic strategies for symptom control and management of long-term complications without erroneously restricting an athlete's ability to play. Utilizing a shared decision-making model is an optimal method for managing expectations and guiding exercise recommendations. Expert commentary: Though pre-participation ECG screening as the standard of care for competitive athletes remains controversial in the United States, a 12-lead ECG is often the first indication of underlying structural heart disease in athletes with PVBs and can therefore identify athletes at greater risk of SCD. Advancements in non-invasive imaging continue to improve in diagnostic potential and prognostication. Invasive therapies provide a curative strategy for refractory PVBs and PVB-induced cardiomyopathy.

Young athletes with ventricular premature beats: Continuing or not intense training and competition?

Isolated ventricular premature beats (VPBs) are commonly found during pre-participation screening in athletes. Currently, the debate about the role of detraining in reducing the number of VPBs is still open. This study evaluated the arrhythmic risk in a population of young competitive athletes who showed VPBs during eligibility evaluation and that did not undergo detraining but continued practicing competitive sports. 3746 consecutive subjects underwent pre-participation screening. Athletes who showed VPBs were selected and underwent second level evaluation (Echocardiogram, 24 hour Holter ECG and Exercise test). Athletes were re-evaluated after a follow-up period (6-48 months) while they continued practicing competitive sports. 5.3% of the whole population showed ventricular arrhythmias. 73% of the subjects showed isolated VPBs. 88% of the subjects showed monomorphic VPBs, and 12% of athletes showed polymorphic VPBs. At echocardiogram, there was not any pathology which contraindicated competitive sport activity. At 24 hour Holter ECG recording, mean number of daily VPBs was 1592±3217 (range 0-16678). At holter ECG follow-up (16±12 months), the median number of VPBs decreased from 93 (IQR 20-3065) to a new value of 72 (IQR 2-1299). Continuing competitive sport in subjects with ventricular arrhythmias even though frequent but with a low grade of complexity and without structural cardiomyopathy does not increase sudden death risk.

Exercise-induced Ventricular Tachycardia/Ventricular Fibrillation in the Normal Heart: Risk Stratification and Management

Exercise-induced ventricular tachycardia (VT) rarely occurs in the absence of organic heart disease. Idiopathic monomorphic VT has an excellent prognosis. The main aspect of the risk stratification process is recognizing subtle forms of organic heart disease, particularly arrhythmogenic right ventricular cardiomyopathy. Exercise-induced polymorphic VT is potentially malignant. Exercise-induced polymorphic VT has also been seen in mitral valve prolapse. Some patients with stable coronary disease, and even healthy athletes, sometimes have short bursts of polymorphic VT during exercise tests but these arrhythmias are usually not reproducible during repeated testing and have unknown long-term clinical significance.

Syncope as a Warning Symptom of Sudden Cardiac Death in Athletes

Clinical evaluation of syncope in the athlete remains a challenge. Although benign mechanisms predominate, syncope may be arrhythmic and precede SCD. Exercise-induced syncope should be regarded as an important alarming symptom of an underlying cardiac disease predisposing to arrhythmic cardiac arrest. All athletes with syncope require a focused and detailed workup for underlying cardiac causes, either structural or electrical. Major aim is to identify athletes at risk and to protect them from SCD. Athletes with potentially life-threatening etiologies of syncope should be restricted from competitive sports.

Screening of athletes: An electrocardiogram is not enough

Professional and amateur athletic training can cause tremendous overload of the cardiovascular system and thus become a trigger of serious and often fatal cardiac events in athletes with a previously undetected underlying cardiovascular disease. Therefore, every athlete should undergo a specialized diagnostic and qualification screening before a training program is prescribed or continued. However, it is still an unresolved issue which of the accessible diagnostic tools should be routinely applied in order to increase the safety of extreme physical training and reduce the risk of sudden cardiac death. Pre-participation athlete evaluation including a standard electrocardiogram (ECG), physical examination, and familial history of cardiovascular diseases is important, but does not always guarantee high diagnostic accuracy. Hence, the aim of this review article is to discuss the controversy over the usefulness of ECG for the detection of cardiovascular diseases in athletes as well as the views on athlete screening methods in Europe and the USA. Differential diagnostic options and screening schemes are also described in particular groups of athletes in reference to their age, cardiovascular risk factors, as well as intensity and type of sport discipline.

Usefulness of ventricular premature complexes in asymptomatic patients ≤21 years as predictors of poor left ventricular function

Although ventricular premature complexes (VPCs) have been shown to correlate with decreased cardiac function in adults, the correlation of left ventricular (LV) function to VPCs in asymptomatic children remains unclear. The aim of this study was to determine the correlation of VPC burden with LV function in asymptomatic pediatric patients with structurally normal hearts. This was a retrospective analysis of patients aged ≤21 years with echocardiograms and 24-hour Holter monitors with ≥0.5% VPCs completed within 60 days of each other. LV fractional shortening (FS) was compared with VPC burden and VPC characteristics. Normal LV function was defined as FS ≥28%. Correlation between VPC burden and LV function was determined by regression analysis. Wilcoxon's rank-sum test was used to compare LV function with VPC characteristics. This study included 123 patients (77 male [63%]). The median age was 11.6 years (interquartile range 5.8 to 14.3). The median VPC burden was 11.2% (interquartile range 4.8% to 18.9%), and median FS was 36% (interquartile range 33% to 38%). There was no significant correlation between VPC burden and LV FS (p = 0.50). The presence of uniform versus multiform VPCs (p = 0.29), ventricular couplets (p = 0.37), or runs of ventricular ectopy (p = 0.19) were not associated with a decrease in LV FS. Twenty-two patients (18%) had VPC burden >24%, none of which had decreased LV FS. In conclusion, there was no significant relation between VPC burden or VPC characteristics and LV systolic function in this pediatric population with structurally normal hearts.

A 24-hour ambulatory ecg monitoring in assessment of qt interval duration and dispersion in rowers with physiological myocardial hypertrophy

Myocardial hypertrophy (MH) due to cardiac pathology is characterized by an increase in QT interval duration and dispersion, while the findings for exercise-induced myocardial hypertrophy are contradictory. The majority of published research findings have not explored this relationship, but there have only been a few conducted studies using 24-hour ECG monitoring. The aim of the study was to determine the QT interval duration and dispersion in short-term and 24-hour ECG in endurance athletes with myocardial hypertrophy and without it.

METHODS

A total of 26 well-trained rowers underwent a resting 12-lead ECG, 24-hour ECG monitoring and echocardiography.

RESULTS

Athletes with MH (n = 7) at rest did not show any increase in QTc interval duration and dispersion, or mean and maximal QTc duration in Holter monitoring compared to athletes without MH (n = 19). Left ventricular mass was not significantly correlated with any QTc characteristics. Furthermore, athletes with MH had significantly longer mean QT (P = 0.01) and maximal QT (P = 0.018) intervals in Holter monitoring and higher 24-hour heart rate variability indexes due to stronger vagal effects.

CONCLUSIONS

The present study demonstrated that athlete's heart syndrome with myocardial hypertrophy as a benign phenomenon does not lead to an increase in QT interval duration, or increases in maximal and mean duration in a 24-hour ECG. An increase in QT interval duration in athletes may have an autonomic nature.

Metallo-beta-lactamases: two binding sites for one catalytic metal ion?

During the past few years the results from molecular biological, biochemical, chemical, physical and theoretical approaches expanded the knowledge about metallo-beta-lactamases considerably. The main reason for the attracted interest is a persisting medical problem. Bacteria expressing metallo-beta-lactamases can be resistant to treatment with all the known beta-lactam antibiotics, and they are additionally invulnerable to combined treatment with inhibitors for the wider-spread serine-beta-lactamases. However, clinically useful inhibitors for metallo-beta-lactamases are not yet available. In spite of the rapidly expanding knowledge base a central question is still controversially discussed: is it the mononuclear, the binuclear or the metal-free state which might serve as the physiologically relevant target for inhibitor design? A summary of the present views of the roles and coordination geometries of metal ion(s) in metallo-beta-lactamases is combined with a discussion of the possibly variable metal ion content under physiological conditions.