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

Prevalence and Clinical Significance of Low QRS Voltages in Patients Presenting for Cardiovascular or Related Diseases

BACKGROUND

We investigated the presence of low QRS voltage (LQRSV) in a large sample population presenting for cardiovascular diseases. Further studies on LQRSV prevalence and clinical implications are warranted.

METHODS

We conducted a cross-sectional study using ECG data from the National Center for Cardiovascular Diseases of China, collected from January 2015 to December 2023. LQRSV was defined as QRS amplitude <0.5 mV in limb leads (L-LQRSV), <1.0 mV in precordial leads (P-LQRSV), or both (C-LQRSV). The primary endpoint was a composite of in-hospital death or discharge against medical advice.

RESULTS

We analyzed ECG data from 712,362 patients, with echocardiographic data from 454,717, cardiac magnetic resonance (CMR) results from 17,712, and hospitalization data from 187,125 patients. LQRSV prevalence was 2.0%, with 81.4% L-LQRSV, 12.3% P-LQRSV, and 6.4% C-LQRSV. The most common cardiomyopathies associated with LQRSV were cardiac amyloidosis (49.4%), arrhythmogenic cardiomyopathy (31.2%), and Takotsubo syndrome (25.7%). C-LQRSV patients exhibited worse echocardiographic parameters and higher prevalence of myocardial fibrosis on CMR compared to those with L-LQRSV or P-LQRSV or normal QRS voltage (NQRSV). LQRSV was an independent predictor of in-hospital death or discharge against medical advice (OR 3.27, 95% CI 2.94-3.64, P < .001), and C-LQRSV conferred the highest risk of primary endpoint (12.41%, OR 8.63, 95% CI 6.72-11.07, P < .001).

CONCLUSIONS

LQRSV is an uncommon ECG pattern associated with severe cardiac dysfunction and the majority presents in limb leads, few in precordial leads, a tiny minority in both. C-LQRSV might be an ominous marker indicating the highest risk of adverse clinical outcomes.

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.

Prevalence and determinants of low QRS voltages and QRS fragmentation in children and adolescents undergoing sports pre-participation screening

AIMS

Low QRS voltages (LQRSV) in limb leads and QRS fragmentation (FQRS) are possible electrocardiographic signs of myocardial fibrosis and cardiomyopathy, but they are not listed in current criteria for interpreting athlete's electrocardiogram (ECG). We investigated the prevalence and determinants of LQRSV and FQRS in a cohort of young apparently healthy athletes undergoing pre-participation screening (PPS).

METHODS AND RESULTS

We analysed a consecutive series of 2140 ECG obtained during PPS of young athletes (mean age 12.5 ± 2.6 years, 7-18-year-old, 49% males). The peak-to-peak QRS voltage was measured in all limb leads, and LQRSV were defined when maximum value was <0.5 mV. Fragmented QRS morphologies were grouped into five patterns. Lead aVR was not considered. Maximum peak-to-peak QRS voltage in limb leads was 1.4 ± 0.4 mV, similar between younger and older athletes, but significantly lower in females than males (1.35 ± 0.38 mV vs. 1.45 ± 0.42 mV; P < 0.001). There was a weak correlation between maximal QRS voltages and body mass index (BMI), but not with type of sport or training load. Only five (0.2%) individuals showed LQRSV. At least one fragmented QRS complex was identified in 831 (39%) individuals but excluding the rSr' pattern in V1-V2, only 10 (0.5%) showed FQRS in ≥2 contiguous leads. They were older than those without FQRS, but did not differ in terms of gender, BMI, type of sport, or training load.

CONCLUSION

Low QRS voltages in limb leads and FQRS in ≥2 contiguous leads excluding V1-V2 are rare in young apparently healthy athletes and are not related to the type and intensity of sport activity. Therefore, they may require additional testing to rule out an underlying disease particularly when other abnormalities are present.

The 2023 European Task Force Criteria for Diagnosis of Arrhythmogenic Cardiomyopathy: Historical Background and Review of Main Changes

Arrhythmogenic cardiomyopathy (ACM) is a cardiac disease featured by non-ischemic myocardial scarring linked to ventricular electrical instability. As there is no single gold-standard test, diagnosing ACM remains challenging and a combination of specific criteria is needed. The diagnostic criteria were first defined and widespread in 1994 and then revised in 2010, approaching and focusing primarily on right ventricular involvement without considering any kind of left ventricular variant or phenotype. Years later, in 2020, with the purpose of overcoming previous limitations, the Padua Criteria were introduced by an international expert report. The main novel elements were the introduction of specific criteria for left ventricular variants as well as the use of cardiac magnetic resonance for tissue characterization and scar detection. The last modifications and refinement of these criteria were published at the end of 2023 as the European Task Force criteria, by a "head-quarter" of ACM international experts, proving the emerging relevance of this condition besides its difficult diagnosis. In this review, emphasizing the progress in understanding the aetiology of the cardiomyopathy, an analysis of the new criteria is presented. The introduction of the term "scarring/arrhythmogenic cardiomyopathy" sets an important milestone in this field, underlying how non-ischemic myocardial scarring-typical of ACM-and arrhythmic susceptibility could be the main pillars of numerous different phenotypic variants regardless of etiology.

Prevalence and clinical significance of low QRS voltages in healthy individuals, athletes, and patients with cardiomyopathy: implications for sports pre-participation cardiovascular screening

Low QRS voltages (LQRSV), defined as a QRS amplitude from peak to nadir < 0.5 mV in all limb leads, are an emerging diagnostic finding on the electrocardiogram (ECG). In healthy individuals and athletes, LQRSV are rare (2.2-4% of elite athletes, 0.5% of recreational athletes, and 0.3% of sedentary individuals). LQRSV athletes commonly show ventricular arrhythmias (VAs) on exercise, and up to 40% of those with LQRSV and VAs have late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR). The prevalence of LQRSV in arrhythmogenic cardiomyopathy ranges from 17-40%, predicts left ventricular (LV) involvement, and is correlated with more extensive LGE replacement on CMR. In hypertrophic cardiomyopathy (HCM), LQRSV ranges from 0.7-11%. LQRSV-HCM patients have more segments with LGE, despite relatively smaller LV mass, suggesting a more advanced clinical stage and a worse prognosis. In dilated cardiomyopathy (DCM), LQRSV range from 6-7%, but may be higher (36%) in certain genetic forms of DCM. On a follow-up, LQRSV are independently associated with incident cardiac events, such as sudden death, sustained ventricular arrhythmia, or appropriate internal cardioverter defibrillator discharge. In cardiac amyloid, LQRSV range from 34-66% and demonstrate a negative prognostic value, with worse clinical outcomes regardless of underlying biologic, genetic, and clinical variables. In conclusion, LQRSV deserve careful consideration for exclusion of arrhythmogenic substrates in healthy individuals, athletes, and patients. While additional research is needed, it is reasonable that LQRSV should trigger clinical investigation to exclude underlying diseases at risk of life-threatening arrhythmias.

Early detection of low QRS voltage and its association with mortality in patients with sepsis

Various electrocardiographic changes occur during sepsis, but data on the clinical importance of a low QRS voltage in sepsis are still limited. We aimed to evaluate the association between low QRS voltage identified early in sepsis and mortality in patients with sepsis. Between September 2019 and December 2020, all consecutive adult patients diagnosed with sepsis in the emergency room or general ward at Samsung Medical Center were enrolled. Patients without a 12-lead electrocardiogram recorded within 48 h of recognition of sepsis were excluded. In 432 eligible patients, 12-lead electrocardiogram was recorded within the median of 24 min from the first recognition of sepsis, and low QRS voltage was identified in 115 (26.6%) patients. The low QRS group showed more severe organ dysfunction and had higher levels of N-terminal pro-brain natriuretic peptide. The hospital mortality was significantly higher in the low QRS voltage group than in the normal QRS voltage group (49.6% vs. 28.1%, p < 0.001). Similarly, among the 160 patients who required intensive care unit admission, significantly more patients in the low QRS group died in the intensive care unit (35.9% vs. 18.2%, p = 0.021). Low QRS voltage was associated with increased hospital mortality in patients with sepsis.

Arrhythmogenic Cardiomyopathy: Current Updates and Future Challenges

Arrhythmogenic cardiomyopathy (ACM) epitomises a genetic anomaly hallmarked by a relentless fibro-fatty transmogrification of cardiac myocytes. Initially typified as a right ventricular-centric disease, contemporary observations elucidate a frequent occurrence of biventricular and left-dominant presentations. The diagnostic labyrinth of ACM emerges from its clinical and imaging properties, often indistinguishable from other cardiomyopathies. Precision in diagnosis, however, is paramount and unlocks the potential for early therapeutic interventions and vital cascade screening for at-risk individuals. Adherence to the criteria established by the 2010 task force remains the cornerstone of ACM diagnosis, demanding a multifaceted assessment incorporating electrophysiological, imaging, genetic, and histological data. Reflecting the evolution of our understanding, these criteria have undergone several revisions to encapsulate the expanding spectrum of ACM phenotypes. This review seeks to crystallise the genetic foundation of ACM, delineate its clinical and radiographic manifestations, and offer an analytical perspective on the current diagnostic criteria. By synthesising these elements, we aim to furnish practitioners with a strategic, evidence-based algorithm to accurately diagnose ACM, thereby optimising patient management and mitigating the intricate challenges of this multifaceted disorder.

Prognostic Electrocardiographic Signs in Arrhythmogenic Cardiomyopathy

Arrhythmogenic cardiomyopathy (ACM) is a rare cardiac disease, characterized by the progressive replacement of myocardial tissue with fibrous and fatty deposits. It can involve both the right and left ventricles. It is associated with the development of life-threatening arrhythmias and culminates in sudden cardiac death. Electrocardiography (ECG) has emerged as a pivotal tool, offering diagnostic insights and prognostic information. The specific ECG abnormalities observed in ACM not only contribute to early detection but also hold the key to the prediction of the likelihood of severe complications. The recognition of these nuanced ECG manifestations has become imperative for clinicians as it guides them in the formulation of tailored therapeutic strategies that address both the present symptoms and the potential future risks.

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.

Proposed diagnostic criteria for arrhythmogenic cardiomyopathy: European Task Force consensus report

Arrhythmogenic cardiomyopathy (ACM) is a heart muscle disease characterized by prominent "non-ischemic" myocardial scarring predisposing to ventricular electrical instability. Diagnostic criteria for the original phenotype, arrhythmogenic right ventricular cardiomyopathy (ARVC), were first proposed in 1994 and revised in 2010 by an international Task Force (TF). A 2019 International Expert report appraised these previous criteria, finding good accuracy for diagnosis of ARVC but a lack of sensitivity for identification of the expanding phenotypic disease spectrum, which includes left-sided variants, i.e., biventricular (ABVC) and arrhythmogenic left ventricular cardiomyopathy (ALVC). The ARVC phenotype together with these left-sided variants are now more appropriately named ACM. The lack of diagnostic criteria for the left ventricular (LV) phenotype has resulted in clinical under-recognition of ACM patients over the 4 decades since the disease discovery. In 2020, the "Padua criteria" were proposed for both right- and left-sided ACM phenotypes. The presently proposed criteria represent a refinement of the 2020 Padua criteria and have been developed by an expert European TF to improve the diagnosis of ACM with upgraded and internationally recognized criteria. The growing recognition of the diagnostic role of CMR has led to the incorporation of myocardial tissue characterization findings for detection of myocardial scar using the late‑gadolinium enhancement (LGE) technique to more fully characterize right, biventricular and left disease variants, whether genetic or acquired (phenocopies), and to exclude other "non-scarring" myocardial disease. The "ring-like' pattern of myocardial LGE/scar is now a recognized diagnostic hallmark of ALVC. Additional diagnostic criteria regarding LV depolarization and repolarization ECG abnormalities and ventricular arrhythmias of LV origin are also provided. These proposed upgrading of diagnostic criteria represents a working framework to improve management of ACM patients.

The Diagnostic Value of the 12-Lead ECG in Arrhythmogenic Left Ventricular Cardiomyopathy: Novel ECG Signs

BACKGROUND

Electrocardiographic (ECG) findings in arrhythmogenic left ventricular cardiomyopathy (ALVC) are limited to small case series.

OBJECTIVES

This study aimed to analyze the ECG characteristics of ALVC patients and to correlate ECG with cardiac magnetic resonance and genotype data.

METHODS

We reviewed data of 54 consecutive ALVC patients (32 men, age 39 ± 15 years) and compared them with 84 healthy controls with normal cardiac magnetic resonance.

RESULTS

T-wave inversion was often noted (57.4%), particularly in the inferior and lateral leads. Low QRS voltages in limb leads were observed in 22.2% of patients. The following novel ECG findings were identified: left posterior fascicular block (LPFB) (20.4%), pathological Q waves (33.3%), and a prominent R-wave in V1 with a R/S ratio ≥0.5 (24.1%). The QRS voltages were lower in ALVC compared with controls, particularly in lead I and II. At receiver-operating characteristic analysis, the sum of the R-wave in I to II ≤8 mm (AUC: 0.909; P < 0.0001) and S-wave in V1 plus R-wave in V6 ≤12 mm (AUC: 0.784; P < 0.0001) effectively discriminated ALVC patients from controls. It is noteworthy that 4 of the 8 patients with an apparently normal ECG were recognized by these new signs. Transmural late gadolinium enhancement was associated to LPFB, a R/S ratio ≥0.5 in V1, and inferolateral T-wave inversion, and a ringlike pattern correlated to fragmented QRS, SV1+RV6 ≤12 mm, low QRS voltage, and desmoplakin alterations.

CONCLUSIONS

Pathological Q waves, LPFB, and a prominent R-wave in V1 were common ECG signs in ALVC. An R-wave sum in I to II ≤8 mm and SV1+RV6 ≤12 mm were specific findings for ALVC phenotypes compared with controls.

Evolving spectrum of arrhythmogenic cardiomyopathy: Implications for Sports Cardiology

Arrhythmogenic cardiomyopathy (ACM) is a genetic heart muscle disease, structurally characterized by progressive fibro-fatty replacement of the normal myocardium and clinically by ventricular arrhythmias (VAs). Predominantly thanks to the use of cardiac magnetic resonance, we have learnt that the spectrum of the disease encompasses not only the classical right ventricular phenotype, but also biventricular and left dominant variants. Sport activity contributes to the phenotypic expression and progression of ACM and may trigger life-threatening VAs and sudden cardiac death (SCD). We conducted a review of the literature about ACM and its implications in Sport Cardiology and summarized the main findings in this topic. Early identification of affected athletes through preparticipation screening (PPS) is fundamental but, while classical right-ventricular or biventricular phenotypes are usually suspected because of electrocardiogram (ECG) and echocardiographic abnormalities, variants with predominant left ventricular involvement are often characterized by normal ECG and unremarkable echocardiography. Usually the only manifestations of such variants are exercise-induced VAs and for this reason exercise testing may empower the diagnostic yield of the PPS. Patients with ACM are not eligible to competitive sports activity, but low-to-moderate intensity physical activity under medical supervision is possible in most cases.

Electroanatomic mapping in athletes: Why and when. An expert opinion paper from the Italian Society of Sports Cardiology

Three-dimensional electroanatomical mapping (EAM) has the potential to identify the pathological substrate underlying ventricular arrhythmias (VAs) in different clinical settings by detecting myocardial areas with abnormally low voltages, which reflect the presence of different cardiomyopathic substrates. In athletes, the added value of EAM may be to enhance the efficacy of third-level diagnostic tests and cardiac magnetic resonance (CMR) in detecting concealed arrhythmogenic cardiomyopathies. Additional benefits of EAM in the athlete include the potential impact on disease risk stratification and the consequent implications for eligibility to competitive sports. This opinion paper of the Italian Society of Sports Cardiology aims to guide general sports medicine physicians and cardiologists on the clinical decision when to eventually perform an EAM study in the athlete, highlighting strengths and weaknesses for each cardiovascular disease at risk of sudden cardiac death during sport. The importance of early (preclinical) diagnosis to prevent the negative effects of exercise on phenotypic expression, disease progression, and worsening of the arrhythmogenic substrate is also addressed.

Arrhythmogenic Cardiomyopathy and Athletes - A Dangerous Relationship

Arrhythmogenic cardiomyopathy (ACM) is a disease characterized by a progressive replacement of myocardium by fibro-adipose material, predisposing to ventricular arrhythmias (VA) and sudden cardiac death (SCD). Its prevalence is estimated at 1:2000 to 1:5000, with a higher incidence in males, and clinical onset is usually between the 2nd and 4th decade of life. The prevalence of ACM in SCD victims is relatively high, making it one of the most common etiologies in young patients with SCD, especially if they are athletes. Cardiac events occur more frequently in individuals with ACM who participate in competitive sports and/or high-intensity training. In effect, exercise activity can worsen RV function in cases of hereditary ACM. Estimating the incidence of SCD caused by ACM in athletes remains challenging, being reported frequency ranging from 3-20%. Here, we review the potential implications of exercising on the clinical course of the classical genetic form of ACM, as well as the diagnostic tools, risk stratification, and the different therapeutic tools available for managing ACM.

The electrocardiogram in non-ischaemic-dilated cardiomyopathy

This article summarizes the main electrocardiogram (ECG) findings in dilated cardiomyopathy (DCM) patients. Recent reports are described in the great 'pot' of DCM peculiar ECG patterns that are typical of specific forms of DCM. Patients with late gadolinium enhancement on CMR, who are at greatest arrhythmic risk, have also distinctive ECG features. Future studies in large DCM populations should evaluate the diagnostic and prognostic value of the ECG.

The value of the 12-lead electrocardiogram in the prediction of sudden cardiac death

Sudden cardiac death (SCD) can be caused by several clinical conditions, overt or misconceived, which recognize different pathophysiologies determining the development of fatal arrhythmic events. In the various forms of structural heart disease such as ischaemic heart disease, cardiomyopathies (e.g. hypertrophic cardiomyopathy, dilated cardiomyopathy, and arrhythmogenic cardiomyopathy), channelopathies (e.g. long-QT syndrome, congenital short QT, Brugada syndrome, early repolarization (ER) syndrome, and idiopathic ventricular fibrillation) but also in the apparently healthy subject, the 12-lead electrocardiogram (ECG) has proved, over the years, to be a reliable and readily available method for stratifying the risk of adverse arrhythmic events and consequently SCD. Several electrocardiographic markers have been shown to be associated with adverse outcomes in different types of patients. Although with different sensitivity and specificity in each clinical condition, depolarization abnormalities, such as QRS fragmentation, Q waves, QRS duration, left posterior fascicular block, low QRS voltage, and left ventricular hypertrophy and similarly repolarization abnormalities as ER pattern, T wave alternans, QT interval, and QT dispersion, have shown significant efficacy in predicting SCD. Despite the advancement of techniques especially in the field of imaging, the correct interpretation of the 12-lead ECG remains, therefore, an effective tool for assessing the possible prognostic outcome in terms of arrhythmic risk and SCD in different types of patients.

Reproducibility of ventricular arrhythmias at exercise testing for prediction of non-ischaemic left ventricular scar in athletes

AIMS

The non-ischaemic left ventricular scar (NILVS) is an emerging substrate of ventricular arrhythmias (VA) in the athlete. We tested the diagnostic value of VA reproducibility at repeated exercise testing (ET).

METHODS AND RESULTS

We included consecutive athletes who underwent cardiac magnetic resonance (CMR) for evaluation of VA and two consecutive ET off-therapy within 12 months. Those with a positive family history of premature sudden death/cardiomyopathy, syncope/pre-syncope, ECG or echocardiography abnormalities, or low-risk VA (exercise-suppressed infundibular or fascicular VA) were excluded. The NILVS was defined as subepicardial/midmyocardial stria of late gadolinium enhancement involving >5% of the LV mass. Reproducibility was defined as the occurrence of VA with the same pattern and behaviour during repeated ET. Of 325 athletes who underwent CMR for evaluation of VA, 75 were included, and 30 showed NILVS involving three [2-4] LV segments. At first ET, athletes with NILVS showed a higher prevalence of exercise-induced VA (93% vs. 53%, P < 0.001), while other VA characteristics did not differ between groups. At repeated ET, reproducibility was observed in 97% of athletes with vs. 13% without NILVS (P < 0.001). The remaining 87% of athletes with normal CMR either did not show any VA at repeated ET (59%) or showed arrhythmias with different patterns, mostly infundibular. Reproducibility yielded a positive predictive value for NILVS of 83% and a negative predictive value of 98%.

CONCLUSION

VA reproducibility at repeated ET predicted an underlying NILVS in athletes with VA and otherwise normal clinical work-up. This finding may improve risk stratification and appropriate CMR referral of athletes with apparently idiopathic VA.