Does physical activity influence Brugada pattern at 12-lead holter 24-hour monitoring?

Introduction Brugada Syndrome (BrS) is a hereditary ion channel disease predisposing young patients to sudden death, characterized by a dynamic electrocardiogram (ECG) pattern with coved ST-segment elevation in right precordial leads, often not apparent at basal ECG assessments. Various factors, such as increased vagal tone, fever and the use of sodium channel-blocking medications, can either reveal or accentuate the pattern; the impact of physical activity (PA) remains unclear. Purpose To evaluate the effects of PA on Brugada (Br) ECG pattern through the assessment of serial Holter monitoring during a follow up of 5 years. The main endpoints were: 1- to investigate the potential accentuation of spontaneous type 1 ECG pattern in physically active Br patients compared to the sedentary group; 2- to verify if there is a significant difference in unmasking spontaneous type 1 ECG pattern between the two groups with induced type 1 ECG; 3- to determine the prevalence of major arrhythmic events during PA. Methods 153 Brugada patients aged between 18 and 55 years were enrolled in the study. Data regarding demographic information, levels of PA, basal ECG and 12-lead Holter were prospectively collected. The cutoff between trained and untrained subjects was set at 4 hours per week, defining trained individuals as "recreational athletes" according to ESC Guidelines. To assess differences between groups, the Mann-Whitney U and Chi-squared test were performed, as appropriate. Logistic regression was employed to evaluate the association between PA and the presence of the pattern, adjusted for sex and age. Results 153 patients were included in the analyses: 121 males (79.1%), median age of 35.2 years. 39 patients (25%) were trained, while 114 (75%) were untrained. Overall sample characteristics are shown in Table.1. 64 Br patients (41.8%) showed a spontaneous type 1 ECG, 89 (58.2%) had a drug-induced type 1 ECG. The median of the average heart rates at the first Holter was significantly lower in trained vs untrained (71 vs 75 bpm, p=0.025). No significant differences were observed regarding prevalence of type 1 pattern in both subgroups with spontaneous (p=0.606) or drug induced type-1 ECG (p=0.363), see Table.2. No significant association emerged between PA and presence of diagnostic Br pattern (OR:1.66; 95%CI:0.75-3.83; p=0.229). Male sex and age were confirmed as risk factors for identifying the pattern during Holter monitoring (OR:5.85; 95%CI:1.89-25.84; p=0.006; and OR per year of age: 1.04; 95% CI:1.00-1.09; p=0.059, respectively). At last, no symptoms or arrhythmic events occurred during PA. Conclusion in the sample population we observed that trained individuals with Br pattern showed significantly lower heart rate during Holter monitoring. However, there was neither a higher prevalence nor a significant unmasking of the type 1 pattern when compared to sedentary patients. During sports activities, we did not observe any events.