Author + information
- aCardiology Clinical Academic Group, St George’s, University of London, London, United Kingdom
- bCenter for Cardiological Innovation, Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
- cInstitute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- ↵∗Address for correspondence:
Dr. Sanjay Sharma, Cardiology Clinical Academic Group, St. George’s, University of London, Cranmer Terrace, London SW17 0RE, United Kingdom.
- arrhythmogenic right ventricular cardiomyopathy
- pre-participation screening
- T-wave inversion
Sudden cardiac death from a quiescent cardiomyopathy is a feared complication of sport in young athletes. Most elite sporting organizations in Europe implement cardiac screening with electrocardiography (ECG) in young athletes to identify affected individuals who may be at risk and in whom athletic activity may accelerate the disease process (1). ECG interpretation in young athletes is challenging because regular intensive exercise is associated with several repolarization anomalies that overlap with those detected in patients with cardiomyopathy. Early repolarization, T-wave inversion (TWI), and a prolonged QT interval are all recognized features of athletic training but are also established markers of cardiac diseases associated with high arrhythmic risk. The differentiation between cardiac electrical and structural markers of physiological adaptation and cardiomyopathy is among the most intriguing aspects of sports cardiology and an area of evolving paradigms and research.
Anterior TWI (leads V1 to V3) is the most commonly recognized electrical abnormality in individuals with arrhythmogenic right ventricular cardiomyopathy (ARVC) but is also present in approximately 10% of white endurance athletes and a larger proportion of black athletes. TWI rarely extends beyond lead V2 in white endurance athletes (1% to 4%) but may affect leads V3 and V4 in 12% to 13% of black athletes where it is frequently preceded by J-point elevation (JPE) ≥0.1 mV and ST-segment elevation. Indeed, this trio of repolarization anomalies is considered a normal ethnic variant in black athletes and does not require further investigation in asymptomatic athletes without a relevant family history. The significance of TWI in leads V2 to V4 in white endurance athletes is less clear, particularly considering emerging reports that intensive endurance exercise may result in adverse electrical and structural remodeling of the right ventricle that is indistinguishable from familial ARVC (2).
Early repolarization in the anterior leads is common in athletes, therefore Calore et al. (3) examined the role of preceding JPE in distinguishing athletes with anterior TWI and individuals with ARVC. Fifty-seven young athletes (median age: 21 years) with TWI in leads V1 to V4 but no other features of ARVC were compared with 26 probands with ARVC including 9 athletes (mean age: 32 years). The investigators concluded that JPE ≤0.1 mV showed a 100% sensitivity for cardiomyopathy and 55% specificity for physiological adaptation. In other words, none of the patients with ARVC and TWI confined to leads V1 to V4 showed JPE ≥0.1 mV, therefore its presence had excellent negative predictive value for ARVC. In contrast, one-half of the healthy athletes with anterior TWI also showed JPE ≤0.1 mV, hence its presence provided limited clinical information.
The low specificity of JPE ≤0.1 mV is not surprising because the prevalence of early repolarization in athletes does not exceed 40% to 50% and is most common in young black male athletes and white male endurance athletes, whereas white female athletes rarely reveal this phenomenon. The sensitivity of this parameter, when applied to the general young sporting population in the Western world, is also questionable because Calore et al. (3) compared predominantly black male athletes (70%) who would be expected to have a high prevalence of JPE, with ARVC patients. Furthermore, the number of patients in this study was relatively small to draw concrete conclusions for a conundrum where an erroneous diagnosis could have potentially serious implications.
In this issue of JACC: Clinical Electrophysiology, Brosnan et al. (4) revisit electrocardiographic features that facilitate the differentiation between athlete’s heart and ARVC. Electrocardiograms in 100 athletes with anterior TWI (62% in leads V1 and V2 only) were compared with ECGs in 100 patients with ARVC who were matched for age, sex, and ethnicity. Both cohorts had a mean age between 21.5 and 22.5 years, respectively, 97% were white, and 53% were female. The ARVC patients were recruited from the Johns Hopkins ARVD/C Registry and The Netherlands Heart Institute ARVC Registry. In contrast with Calore et al. (3), Brosnan et al. (4) did not notice any difference in the prevalence of JPE ≥0.1 mV between athletes and patients with ARVC (27% vs. 16%; p = 0.09) (4). The prevalence of JPE ≥0.1 mV in patients with ARVC is much higher than previous reports in patients who were between 10 and 20 years older than the current cohort (3,5) and could be due to several age-related factors including progression of disease severity and changes in cardiac vagal tone. JPE ≤0.1 mV preceding anterior TWI (leads V1 to V4) showed a sensitivity of 92% for detecting ARVC this young, nonblack, and predominantly female cohort. Although this parameter would not have detected 8% of affected individuals, this figure is not dissimilar to that reported for a normal ECG in young individuals with hypertrophic cardiomyopathy. Of more interest was the 10-fold higher prevalence of JPE ≥0.2 mV in athletes compared with patients with ARVC, suggesting that higher JPE is more useful for excluding ARVC with a sensitivity reaching 98%. The specificity of JPE for predicting athlete’s heart is even poorer in white athletes and should not be considered further.
Brosnan et al. (4) identified several other parameters that were more predictive of ARVC than athlete’s heart including TWI beyond lead V3 or inferior leads, premature ventricular complexes on a 10-s ECG and low limb lead voltages. TWI beyond V4 and premature ventricular complexes were not identified in any athlete. Furthermore, TWI in the inferior leads were identified in only 3% athletes compared with 31% patients with ARVC and low limb lead complexes were noted in only 1 athlete compared with 21% of ARVC patients. A separate analysis in 30 ARVC patients who exercised regularly also revealed a much higher prevalence of these anomalies compared with healthy athletes.
The strength of this study is the matched design for similar age, sex, and ethnicity between ARVC patients and athletes, all of which are confounders in prevalence of JPE. Apart from a lower sensitivity of JPE ≤0.1 mV for detecting ARVC in this cohort, the findings are not dissimilar to those reported recently by Finocchiaro et al. (5) who investigated 129 healthy individuals (athletes) of similar age who were compared with 82 patients with ARVC who were 20 years older. Healthy individuals had been investigated comprehensively for ARVC. Although only 2% of this older cohort of ARVC patients showed JPE ≥0.1 mV, these patients had a higher prevalence of other ECG anomalies in addition to anterior TWI (77% vs. 19%). Finocchiaro et al. (5) excluded young healthy individuals with inferior and lateral TWI because these anomalies are considered abnormal in white athletes and warrant investigation. As with this study, over 30% of ARVC patients had inferior TWI and 29% showed lateral TWI. The prevalence of lower limb lead complexes was also higher in ARVC patients (15% vs. 4%). In contrast with the current study, premature ventricular complexes were observed in 2% of healthy athletes. Additionally, 28% ARVC patients showed S-wave duration >55 ms in V2 whereas none of the healthy athletes did.
There have been several developments in our understanding of the ECG in patients with ARVC. Whereas anterior TWI in leads V1 to V3 is common in patients with ARVC and some athletes, there are several other anomalies that appear to be strong discriminators between the 2 entities. The heterogeneous nature of ARVC, variable involvement of the left ventricle, and overt contribution of environmental stimuli to disease phenotype represent a challenge in finding single parameters with high sensitivity and specificity, however an algorithm that incorporates a plethora of anomalies is beginning to pave an optimistic path.
↵∗ Editorials published in JACC: Clinical Electrophysiology reflect the views of the authors and do not necessarily represent the views of JACC: Clinical Electrophysiology or the American College of Cardiology.
The authors have reported that they have no relationships relevant to the contents of this paper to disclose. Katja Zeppenfeld, MD, served as Guest Editor for this paper.
All authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the JACC: Clinical Electrophysiology author instructions page.
- 2018 American College of Cardiology Foundation
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