Papadakis, Michael

Abstract Aims SCN5A-E1784K (c.5350G>A) is the most common variant associated with the long QT (LQTS) and Brugada syndromes (BrS). It can manifest variably as LQTS, BrS, and/or conduction disorders. This presents a challenge for risk stratification. We aimed to describe clinical and ECG characteristics and identify risk markers that associate with arrhythmic events. Methods and results We undertook a retrospective observational multicentre study of a large cohort of 231 subjects with SCN5A-E1784K from Europe, USA, and Japan. Comprehensive demographic and clinical data, including initial presentation ECG and follow-up, were collected. ‘Lethal events’ were defined as sudden death, non-fatal cardiac arrest, and documented sustained VT or VF. ‘Cardiac events’ were defined as arrhythmic syncope plus any lethal events. Clinical characteristics and ECG parameters corrected for age were investigated for association with lethal and/or cardiac events. Fourteen (6%) subjects experienced a lethal event and 45 (19%) a cardiac event. PR interval and QRS duration were associated with lethal and cardiac events. In multivariable models, both PR interval and QRS duration were associated with lethal events, but only QRS duration was associated with cardiac events. Only age-corrected QRS (rQRS) was associated with lethal and cardiac event-free survival from birth after correction for multiple testing. Conclusion Ventricular myocardial conduction appears likely to play a role in the risk of arrhythmic events in patients with SCN5A-E1784K. This provides an important opportunity for the personalization of management and has the potential to guide preventative therapies.

Abstract Exercise training improves cardiovascular health and reduces the risk for future cardiovascular events and mortality. However, emerging evidence suggests that Masters athletes may have a higher prevalence of cardiovascular abnormalities, such as atrial arrhythmias, coronary atherosclerosis, aortic dilatation, and myocardial fibrosis, compared to their less active peers. The clinical management of Masters athletes may be challenging as available guidelines for such conditions are generally based on data derived from symptomatic sedentary patients, limiting their applicability to highly trained individuals. Other unique challenges in the clinical assessment of Masters athletes include differences in symptomatic presentations compared to sedentary individuals, potential resistance to the initiation of pharmacologic treatment, and the increasing availability of consumer wearable health data that may provide relevant information on their cardiovascular health status. The purpose of this joint EAPC/ESC and ACC Clinical Consensus Statement is to provide an in-depth update on the current state of knowledge on abnormal cardiovascular findings in Masters athletes. We present an expert-based approach on the diagnostic assessment, management, and prognosis of (i) atrial fibrillation, (ii) bradyarrhythmias, (iii) ventricular arrhythmias, (iv) coronary atherosclerosis, (v) aortic dilatation, (vi) myocardial fibrosis, and (vii) exercise-induced arrhythmogenic cardiomyopathy. Clinical challenges, areas of ongoing controversy, and uncertainty and the potential underlying mechanisms are discussed. We also present future perspectives and research directives to further refine current best practice strategies. This includes the need for clinical outcome studies, dedicated randomized controlled trials in athletes, and international registries with diverse populations and longitudinal follow-up to evaluate the natural history of cardiac abnormalities and facilitate development of evidence-based approaches in the clinical management of Masters athletes with cardiovascular abnormalities.

Background: Brugada syndrome (BrS) is characterized by the type 1 Brugada ECG pattern. Pathogenic rare variants in SCN5A (mutations) are identified in 20% of BrS families in whom incomplete penetrance and genotype-negative phenotype-positive individuals are observed. E1784K- SCN5A is the most common SCN5A mutation identified. We determined the association of a BrS genetic risk score (BrS-GRS) and SCN5A mutation type on BrS phenotype in BrS families with SCN5A mutations. Methods: Subjects with a spontaneous type 1 pattern or positive/negative drug challenge from cohorts harboring SCN5A mutations were recruited from 16 centers (n=312). Single nucleotide polymorphisms previously associated with BrS at genome-wide significance were studied in both cohorts: rs11708996, rs10428132, and rs9388451. An additive linear genetic model for the BrS-GRS was assumed (6 single nucleotide polymorphism risk alleles). Results: In the total population (n=312), BrS-GRS ≥4 risk alleles yielded an odds ratio of 4.15 for BrS phenotype ([95% CI, 1.45–11.85]; P =0.0078). Among SCN5A -positive individuals (n=258), BrS-GRS ≥4 risk alleles yielded an odds ratio of 2.35 ([95% CI, 0.89–6.22]; P =0.0846). In SCN5A -negative relatives (n=54), BrS-GRS ≥4 alleles yielded an odds ratio of 22.29 ([95% CI, 1.84–269.30]; P =0.0146). Among E1784K- SCN5A positive family members (n=79), hosting ≥4 risk alleles gave an odds ratio=5.12 ([95% CI, 1.93–13.62]; P =0.0011). Conclusions: Common genetic variation is associated with variable expressivity of BrS phenotype in SCN5A families, explaining in part incomplete penetrance and genotype-negative phenotype-positive individuals. SCN5A mutation genotype and a BrS-GRS associate with BrS phenotype, but the strength of association varies according to presence of a SCN5A mutation and severity of loss of function.