Electrocardiographic Features Differentiating Arrhythmogenic Right Ventricular Cardiomyopathy From an Athlete’s Heart

Should ECG criteria for Low QRS voltage (LQRSV) be specific for Sex?

INTRODUCTION

Low QRS peak-to-nadir voltage (LQRSV) is associated with arrhythmogenic right ventricular cardiomyopathy (ARVC) and other cardiomyopathies. Recent studies have proposed criteria for LQRSV when screening athletes for cardiovascular disease. These criteria have not yet been evaluated in a large population of healthy young athletes.

METHODS

The target population was 10,728 (42.5% female, 57.5% male, mean age 18.1 ± 4.3 years) athletes who participated in mass ECG screenings between 2014 and 2021 at multiple sites across the United States including grade schools (11%), high schools (32%), colleges (50%), and professional athletic teams (6%) with digitally recorded ECGs and a standardized protocol. Since by design, complete follow up for outcomes and the results of testing were not available. Including only ECGs from initial evaluation among athletes 14-35 years of age and excluding those with right bundle branch block, left bundle branch block, Wolf-Parkinson-White pattern, reversed leads and 3 clinically diagnosed cardiomyopathies at Stanford, 8,679 (58% males, 42% females) remained eligible for analysis. QRS voltage was analyzed for each ECG lead and LQRSV criteria were applied and stratified by sex.

RESULTS

QRS voltage was lower in all leads in female athletes compared to male athletes. Using traditional limb lead criteria or precordial lead criteria, the prevalence of LQRSV was significantly lower in males than females (P < .001). Strikingly, LQRSV using the Sokolow-Lyon Index was present in 1.9% of males and 9.8% of females (P < .001). Applying first percentile for LQRS amplitude criteria provided possible values for screening young athletes for LQRSV.

CONCLUSIONS

LQRSV is more common among female athletes than male athletes using established criteria. Using first percentile sex-specific cut points should be considered in future analyses. Proposed novel LQRSV criteria in young athletes should be specific for males and females.

The International Criteria for Electrocardiogram Interpretation in Athletes: Common Pitfalls and Future Directions

Preparticipation cardiovascular screening (PPCS) in young athletes is performed to detect conditions associated with sudden cardiac death. Many medical societies and sports governing bodies support the addition of a 12-lead electrocardiogram (ECG) to the history and physical to improve PPCS sensitivity. The current standard for ECG interpretation in athletes, the International Criteria, was developed to distinguish physiologic from pathologic ECG findings in athletes. Although application of the International Criteria has reduced the PPCS false-positive rate, interpretative challenges and potential areas of improvement remain. This review provides an overview of common pitfalls and future directions for ECG interpretation in athletes.

Structural Progression in Patients with Definite and Non-Definite Arrhythmogenic Right Ventricular Cardiomyopathy and Risk of Major Adverse Cardiac Events

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare inherited disease characterised by early arrhythmias and structural changes. Still, there are limited echocardiography data on its structural progression. We studied structural progression and its impact on the occurrence of major adverse cardiovascular events (MACE). In this single-centre observational cohort study, structural progression was defined as the development of new major or minor imaging 2010 Task Force Criteria during follow-up. Of 101 patients, a definite diagnosis of ARVC was made in 51 patients, while non-definite 'early' disease was diagnosed in 50 patients. During 4 years of follow-up (IQR: 2-6), 23 (45%) patients with a definite diagnosis developed structural progression while only 1 patient in the non-definite (early) group gained minor imaging Task Force Criteria. Male gender was strongly associated with structural progression (62% of males progressed structurally, while 88% of females remained stable). Patients with structural progression were at higher risk of MACE (64% of patients with MACE had structural progression). Therefore, the rate of structural progression is an essential factor to be considered in ARVC studies.

Electrocardiographic abnormalities in patients with cardiomyopathies

Abnormalities in impulse generation and transmission are among the first signs of cardiac remodeling in cardiomyopathies. Accordingly, 12-lead electrocardiogram (ECG) of patients with cardiomyopathies may show multiple abnormalities. Some findings are suggestive of specific disorders, such as the discrepancy between QRS voltages and left ventricular (LV) mass for cardiac amyloidosis or the inverted T waves in the right precordial leads for arrhythmogenic cardiomyopathy. Other findings are less sensitive and/or specific, but may orient toward a specific diagnosis in a patient with a specific phenotype, such as an increased LV wall thickness or a dilated LV. A "cardiomyopathy-oriented" mindset to ECG reading is important to detect the possible signs of an underlying cardiomyopathy and to interpret correctly the meaning of these alterations, which differs in patients with cardiomyopathies or other conditions.

The intercalated disc: a unique organelle for electromechanical synchrony in cardiomyocytes

The intercalated disc (ID) is a highly specialized structure that connects cardiomyocytes via mechanical and electrical junctions. Although described in some detail by light microscopy in the 19th century, it was in 1966 that electron microscopy images showed that the ID represented apposing cell borders and provided detailed insight into the complex ID nanostructure. Since then, much has been learned about the ID and its molecular composition, and it has become evident that a large number of proteins, not all of them involved in direct cell-to-cell coupling via mechanical or gap junctions, reside at the ID. Furthermore, an increasing number of functional interactions between ID components are emerging, leading to the concept that the ID is not the sum of isolated molecular silos but an interacting molecular complex, an "organelle" where components work in concert to bring about electrical and mechanical synchrony. The aim of the present review is to give a short historical account of the ID's discovery and an updated overview of its composition and organization, followed by a discussion of the physiological implications of the ID architecture and the local intermolecular interactions. The latter will focus on both the importance of normal conduction of cardiac action potentials as well as the impact on the pathophysiology of arrhythmias.

The International Criteria for Electrocardiogram Interpretation in Athletes: Common Pitfalls and Future Directions

Preparticipation cardiovascular screening (PPCS) in young athletes is performed to detect conditions associated with sudden cardiac death. Many medical societies and sports governing bodies support the addition of a 12-lead electrocardiogram (ECG) to the history and physical to improve PPCS sensitivity. The current standard for ECG interpretation in athletes, the International Criteria, was developed to distinguish physiologic from pathologic ECG findings in athletes. Although application of the International Criteria has reduced the PPCS false-positive rate, interpretative challenges and potential areas of improvement remain. This review provides an overview of common pitfalls and future directions for ECG interpretation in athletes.

Clinical Features, Genetic Findings, and Risk Stratification in Arrhythmogenic Right Ventricular Cardiomyopathy: Data From a Brazilian Cohort

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy (ARVC), a rare inherited disease, causes ventricular tachycardia, sudden cardiac death, and heart failure (HF). We investigated ARVC clinical features, genetic findings, natural history, and the occurrence of life-threatening arrhythmic events (LTAEs), HF death, or heart transplantation (HF-death/HTx) to identify risk factors.

METHODS

The clinical course of 111 consecutive patients with definite ARVC, predictors of LTAE, HF-death/HTx, and combined events were analyzed in the entire cohort and in a subgroup of 40 patients without sustained ventricular arrhythmia before diagnosis.

RESULTS

The 5-year cumulative probability of LTAE was 30% and HF-death/HTx was 10%. Predictors of HF-death/HTx were reduced right ventricle ejection fraction (HR: 0.93; P=0.010), HF symptoms (HR: 4.37; P=0.010), epsilon wave (HR: 4.99; P=0.015), and number of leads with low QRS voltage (HR: 1.28; P=0.001). Each additional lead with low QRS voltage increased the risk of HF-death/HTx by 28%. Predictors of LTAE were prior syncope (HR: 1.81; P=0.040), number of leads with T wave inversion (HR: 1.17; P=0.039), low QRS voltage (HR: 1.12; P=0.021), younger age (HR: 0.97; P=0.006), and prior ventricular arrhythmia/ventricular fibrillation (HR: 2.45; P=0.012). Each additional lead with low QRS voltage increased the risk of LTAE by 17%. In patients without ventricular arrhythmia before clinical diagnosis of ARVC, the number of leads with low QRS voltage (HR: 1.68; P=0.023) was independently associated with HF-death/HTx.

CONCLUSIONS

Our study demonstrated the characteristics of a specific cohort with a high prevalence of arrhythmic burden at presentation, male predominance, younger age and HF severe outcomes. Our main results suggest that the presence and extension of low QRS voltage can be a risk predictor for HF-death/HTx in ARVC patients, regardless of the arrhythmic risk. This study can contribute to the global ARVC risk stratification, adding new insights to the international current scientific knowledge.

Prevalence and clinical significance of isolated low QRS voltages in young athletes

AIMS

Low QRS voltages (peak to peak <0.5 mV) in limb leads (LQRSV) on the athlete's electrocardiogram (ECG) may reflect an underlying cardiomyopathy, mostly arrhythmogenic cardiomyopathy (ACM) or non-ischaemic left ventricular scar (NILVS). We studied the prevalence and clinical meaning of isolated LQRSV in a large cohort of competitive athletes.

METHODS AND RESULTS

The index group included 2229 Italian competitive athletes [median age 18 years (16-25), 67% males, 97% Caucasian] without major ECG abnormalities at pre-participation screening. Three control groups included Black athletes (N = 1115), general population (N = 1115), and patients with ACM or NILVS (N = 58). Echocardiogram was performed in all athletes with isolated LQRSV and cardiac magnetic resonance (CMR) in those with ventricular arrhythmias or echocardiographic abnormalities. The isolated LQRSV pattern was found in 1.1% index athletes and was associated with increasing age (median age 28 vs. 18 years; P < 0.001), elite status (71% vs. 34%; P < 0.001), body surface area, and body mass index but not with sex, type of sport, and echocardiographic left ventricular mass. The prevalence of isolated LQRSV was 0.2% in Black athletes and 0.3% in young individuals from the general population. Cardiomyopathy patients had a significantly greater prevalence of isolated LQRSV (12%) than index athletes, Black athletes, and general population. Five index athletes with isolated LQSRV and exercise-induced ventricular arrhythmias underwent CMR showing biventricular ACM in 1 and idiopathic NILVS in 1.

CONCLUSIONS

Unlike cardiomyopathy patients, the ECG pattern of isolated LQRSV was rarely observed in athletes. This ECG sign should prompt clinical work-up for exclusion of an underlying cardiomyopathy.

Running the Risk: Exercise and Arrhythmogenic Cardiomyopathy

Purpose of review

The purpose of this review is to summarize what is known about the relationship between exercise and arrhythmogenic right ventricular cardiomyopathy (ARVC) with regard to disease onset, diagnosis, progression, and clinical severity. This relationship forms the basis of the management recommendations for restricting physical activity in individuals with and at risk for ARVC.

Recent findings

While ARVC can be challenging to diagnose, there are several diagnostic testing and imaging modalities that may help distinguish athletic heart remodeling from ARVC. There is an increased risk of adverse clinical outcomes in ARVC from endurance and competitive sports participation, including a dose-dependent relationship between exercise intensity and risk of disease penetrance and progression.

Summary

High-intensity exercise can lead to earlier disease onset, increased penetrance, and clinical progression among individuals with and at risk for ARVC. Both amount and intensity of exercise are correlated with adverse outcomes, including ventricular arrhythmias and worsening biventricular function. All individuals with and at risk for ARVC should undergo detailed clinical phenotyping and risk stratification to reduce the risk of such outcomes, including sudden cardiac death. Consensus guidelines recommend against participation in competitive or high-intensity and endurance exercise for individuals with and at risk for ARVC.

A Novel Diagnostic Score Integrating Atrial Dimensions to Differentiate between the Athlete's Heart and Arrhythmogenic Right Ventricular Cardiomyopathy

Objective: The 2010 Task Force Criteria (TFC) have not been tested to differentiate ARVC from the athlete’s heart. Moreover, some criteria are not available (myocardial biopsy, genetic testing, morphology of ventricular tachycardia) or subject to interobserver variability (right ventricular regional wall motion abnormalities) in clinical practice. We hypothesized that atrial dimensions are useful and robust to differentiate between both entities and proposed a new diagnostic score based upon readily available parameters including echocardiographic atrial dimensions. Methods: In this observational study, 21 patients with definite ARVC were matched for age, gender and body mass index to 42 athletes. Based on ROC analysis, the following parameters were included in the score: indexed right/left atrial volumes ratio (RAVI/LAVI ratio), NT-proBNP, RVOT measurements (PLAX and PSAX BSA-corrected), tricuspid annular motion (TAM), precordial TWI and depolarization abnormalities according to TFC. Results: ARVC patients had a higher RAVI/LAVI ratio (1.76 ± 1.5 vs. 0.87 ± 0.2, p < 0.001), lower right ventricular function (fac: 29 ± 10.1 vs. 42.2 ± 5%, p < 0.001; TAM: 19.8 ± 5.4 vs. 23.8 ± 3.8 mm, p = 0.001) and higher serum NT-proBNP levels (345 ± 612 vs. 48 ± 57 ng/L, p < 0.001). Our score showed a good performance, which is comparable to the 2010 TFC using those parameters, which are available in routine clinical practice (AUC93%, p < 0.001 (95%CI 0.874–0.995) vs. AUC97%, p < 0.001 (95%CI 0.93–1.00). A score of 6/12 points yielded a specificity of 91% and an improved sensitivity of 67% for ARVC diagnosis as compared to a sensitivity of 41% for the abovementioned readily available 2010 TFC. Conclusions: ARVC patients present with significantly larger RA compared to athletes, resulting in a greater RAVI/LAVI ratio. Our novel diagnostic score includes readily available clinical parameters and has a high diagnostic accuracy to differentiate between ARVC and the athlete’s heart.

Criteria for interpretation of the athlete's ECG: A critical appraisal

The electrocardiogram (ECG) is cheap and widely available but its use as a screening tool for early identification of athletes with a cardiac disease at risk of sudden cardiac death is controversial because of presumed low specificity. In the last decade, several efforts have been made to improve the distinction between physiological and pathological ECG findings in the athlete, leading to continuous evolution of the interpretation criteria. The most recent 2017 International criteria grouped ECG changes into three categories: normal, borderline, and abnormal. Borderline findings warrant further investigations only when two or more are present while abnormal changes should always be considered as the sign of a possible underlying disease. This review encompasses the evolution of the athlete's ECG interpretation criteria and highlights areas of uncertainty that will need to be addressed by further studies.

The arrhythmogenic right ventricular cardiomyopathy in comparison to the athletic heart

Intense exercise-induced right ventricular remodeling is a potential adaptation of cardiac function and structure. The features of the remodeling may overlap with those of a very early form of arrhythmogenic right ventricular cardiomyopathy (ARVC): at this early stage, it could be difficult to discriminate ARVC, from exercise-induced cardiac adaptation that may develop in normal individuals. The purpose of this paper is to discuss which exercise-induced remodeling may be a pathological or a physiological finding. A complete evaluation may be required to identify the pathological features of ARVC that would include potential risk of sudden cardiac death during sport or, to avoid the false diagnosis of ARVC. The most recent expert assessment of arrhythmogenic cardiomyopathy focuses on endurance athletes presenting with clinical features indistinguishable from ARVC.

Interpretation of T-wave inversion in physiological and pathological conditions: Current state and future perspectives

The presence of T‐wave inversion (TWI) at 12‐lead electrocardiogram (ECG) in competitive athletes is one of the major diagnostic challenges for sports physicians and consulting cardiologists. Indeed, while the presence of TWI may be associated with some benign conditions and it may be occasionally seen in healthy athletes presenting signs of cardiac remodeling, it may also represent an early sign of an underlying, concealed structural heart disease or life‐threatening arrhythmogenic cardiomyopathies, which may be responsible for exercise‐related sudden cardiac death (SCD). The interpretation of TWI in athletes is complex and the inherent implications for the clinical practice represent a conundrum for physicians. Accordingly, the detection of TWI should be viewed as a potential red flag on the ECG of young and apparently healthy athletes and warrants further investigations because it may represent the initial expression of cardiomyopathies that may not be evident until many years later and that may ultimately be associated with adverse outcomes. The aim of this review is, therefore, to report an update of the literature on TWI in athletes, with a specific focus on the interpretation and management.