BACKGROUND:Brugada syndrome (BrS) continues to pose clinical challenges, despite 3 decades of dedicated research and therapeutic advancements. The pivotal role of implantable cardioverter-defibrillator (ICD) therapy in safeguarding high-risk BrS patients from sudden cardiac death due to ventricular arrhythmias is undeniable. However, the debate on risk stratification and the use of ICDs for primary prevention remains ongoing. OBJECTIVES:This study aimed to evaluate the clinical features, management, and long-term outcomes of ICD therapy in patients with Brugada syndrome. METHODS:BrS-diagnosed patients were prospectively enrolled. Inclusion criteria were: 1) a Brugada type 1 electrocardiogram pattern, either spontaneous or drug induced; 2) ICD implantation; and 3) consistent follow-up. Risk stratification was based on prior arrhythmic events, and the multiparametric Brussel risk score was used from 2017. High-risk patients underwent video-thoracoscopic epicardial ablation starting in 2016. ICD implantation strategies evolved over time, guided by patients' clinical and demographic characteristics. RESULTS:A total of 306 consecutive Brugada patients (186 male [61%]; mean age 41 ± 17 years; range: 1-82 years) received ICDs at our institution from 1992 to 2022. ICDs were implanted for secondary prevention in 16% of patients. Over the 3 decades, the proportions of secondary prevention implants and asymptomatic patients remained stable, while risk factors fluctuated in the first two decades before stabilizing. During long-term follow-up (median 103 months [63-147 months]), 14% of patients experienced at least 1 sustained ventricular arrhythmia (VA) (1.59 per 100 person-years), 15% had at least 1 inappropriate ICD shock-unaffected by the presence of single or dual leads-and 27% required device revision and/or lead replacement. Patients with secondary prevention ICDs had a higher incidence of both ventricular and supraventricular arrhythmias compared to those with primary prevention ICDs. Loss-of-function mutations and prior nonsustained VAs were associated with sustained VAs. Among high-risk patients, those who underwent epicardial ablation experienced significantly fewer ventricular events. The overall mortality rate was 5.88%, with 22.2% of deaths attributed to cardiac causes. CONCLUSIONS:This 30-year study highlights ICD therapy's critical role in preventing fatal arrhythmias in Brugada syndrome, but also reveals frequent device-related complications, especially in younger patients. Thoracoscopic epicardial ablation significantly reduced VA in high-risk patients, offering a promising adjunctive therapy. These findings emphasize the need for individualized treatment strategies to balance the benefits of ICDs with their risks, and underscore the potential of ablation to improve long-term outcomes.

Polymorphic ventricular tachycardia (PMVT) is characterized by a typical change in QRS morphology and amplitude. This study aims to evaluate human PMVT mechanisms through in vivo ECG imaging (ECGI) mapping in patients with a normal QTc. All patients from UZ Brussel and CHU Bordeaux were screened. The inclusion criterion for the study was PMVT mapped with ECGI. Exclusion criteria were as follows: (1) long QT, (2) premature ventricular contractions inducing PMVT, and (3) acute ischemia. Phase mapping was performed for each PMVT episode, and rotational and focal activity was adjudicated. A total of five patients were analyzed, and five episodes of PMVT were mapped. PMVT duration was 5.9 s, and the cycle length was 242.4 ms. The mean number of rotational activities was 2.5 ± 1.2, with a mean of 2.9 rotations on the apex. The mean number of focal activities was 1.4 ± 0.9. PMVT mechanism was consistent with the following. In the first phase of PMVT, a stable rotor was found over the ventricular apex. The reduction of QRS amplitude in PMVT was associated with the appearance of a non-apical activity. The further reduction of QRS amplitude (trough or minimum) was secondary to a fusion between the apical wavefront and the non-apical wavefront. In the second phase of PMVT, a stable rotational or focal activity was found. The main mechanism of human PMVT maintenance was rotational activity over the ventricular apex. Changes in QRS morphology and amplitude were secondary to a fusion between apical and non-apical activities. The main mechanism of human polymorphic ventricular tachycardia maintenance is rotational activity over the ventricular apex. Changes in QRS morphology and amplitude are secondary to a fusion between apical and non-apical activities.

AIMS:In patients with Brugada syndrome (BrS), diagnosis relies primarily on the presence of the characteristic type 1 electrocardiographic (ECG) pattern. The aim of this study was to propose an alternative diagnostic method in situations where ECG alone is uncertain. METHODS AND RESULTS:This study was conducted in two phases: (i) Phase 1: cut-off determination. Controls and BrS patients were analysed to develop a predictive model based on electrocardiographic imaging (ECGi) parameters for the diagnosis of BrS. Patients with right bundle branch block (RBBB) were analysed separately. All patients underwent ajmaline infusion. Concealed BrS patients were evaluated in both the absence and presence of a type 1 ECG pattern. The right and left ventricular 'epicardium' maps obtained with ECGi were divided into eight regions, and the mean activation time (ATm) was calculated for each region. The ATm for each area was normalized to QRS length (ATm%); ATm and ATm% were compared across populations. (ii) Phase 2: cut-off validations. A new cohort of control and BrS patients was used to perform a blinded validation of the proposed method. In Phase 1 (cut-off determination), 57 patients affected by BrS, and 10 controls were included. Analysis of ATm and ATm% in right ventricular outflow tract (RVOT) showed significant differences between controls and BrS patients both with either concealed or manifested Pattern 1 ECG (3 721 ± 6.23 vs. 68.33 ± 14.73 ms, P < 0.001; 37.21 ± 6.23 vs. 107.57 ± 21.16 ms, P < 0.001). The relationship between the anterior-RV and the RVOT ATm was used to develop a predictive model to identify a diagnostic threshold for BrS diagnosis. An increase of 45% in anterior-RV ATm was determined to be the optimal predictor of delayed RVOT activation in BrS patients (area under the receiver operating characteristic curve = 0.97, accuracy = 0.92, F-score = 0.95). In RBBB patients, the ATm delay cut-off was reached exclusively in cases with concomitant BrS. In Phase 2, 7 out of 7 control patients exhibited a percentage increase between the anterior-RV and RVOT of <45%. Among BrS patients with concealed pattern (pattern-concealed), 11 out of 20 showed a percentage increase >45% (accuracy 67%). In BrS patients with manifested Pattern 1 (pattern-positive), 19 out of 20 showed a percentage increase of >45% (accuracy 96%). CONCLUSION:In BrS, the delay in RVOT activation can be identified using a threshold value of 45% above the mean activation time in the anterior-RV for each patient, offering a reliable diagnostic tool when standard ECG method alone falls short.

Abstract Background/introduction Brugada syndrome (BrS) is associated with ventricular fibrillation (VF) and polymorphic ventricular tachycardia (PMVT). Different mechanisms have been described for human PMVT, including epicardial drifting of rotational activity before stabilization on the apex. Purpose The aim of this study is mapping human PMVT mechanisms in BrS with ECG imaging (ECGI) in-vivo. Methods All BrS patients, were prospectively enrolled between 1992 and 2022. Inclusion criteria for the study were: 1) BrS diagnosis; 2) PMVT mapped with ECGI during thoracoscopic epicardial right ventricle outflow tract ablation. PMVT was adjudicated if a changing QRS pattern was present. Phase mapping was performed for each PMVT. All maps were imported on a dedicated software and analyzed offline. Left anterior descending coronary artery was added, based on CT scan reconstruction as a reference for the interventricular septum (in grey in Figure 1). Phase maps were performed using the Hilbert transform on detrended signals and the phases of wavefront propagation were color-coded. Rotational activity was defined as a continuous progression of phase from -π to +π around a phase singularity point. Focal activity was defined as a wavefront that appears de novo, without arising from another wavefront and spreading from its origin. Results A total of 21 BrS patients with VF were analyzed and 2 patients (9.5%) were found with PMVT. A total of 2 episodes of PMVT were mapped (one for each BrS patient) with a duration of 2.9 s and 1.3 s, respectively. Both PMVT had spontaneous initiation and termination. The mean number of rotational activities was 2.45 ± 0.07, with a mean of 2.9 ± 0.71 rotations on the apex and 0.8 ± 1.13 rotations on the septum. No other rotational activity was observed. There were 2 and 1 focal activities on the septum, respectively. No other focal activity was observed. The phase mapping of both PMVT episodes was consistent with the mechanism shown in Figure 1. In the first phase of PMVT (negative QRS) a stable rotor (white arrow) is found over ventricular apex (Figure 1, Panels A-D). In Figure 1, Panel E a septal activity appears (yellow arrow). The reduction of QRS voltage is secondary to a fusion between septal (yellow arrow) and apical (white arrow) rotational activities (Figure 1, Panels F-G). In the second phase of PMVT (positive QRS) a stable focal activity (yellow arrow) is found over the ventricular septum (Figure 1, Panels H-J). Conclusion In patients with BrS, change in the QRS pattern during PMVT is secondary to a fusion between rotational septal and apical activities.Figure 1

BACKGROUND:A pathogenic/likely pathogenic variant can be found in 20% to 25% of patients with Brugada syndrome (BrS) and a pathogenic/likely pathogenic variant in SCN5A is associated with a worse prognosis. The aim of this study is to define the diagnostic yield of a large gene panel with American College of Medical Genetics and Genomics variant classification and to assess prognosis of SCN5A and non-SCN5A variants.METHODS:All patients with BrS, were prospectively enrolled in the Universitair Ziekenhuis Brussel registry between 1992 and 2022. Inclusion criteria for the study were (1) BrS diagnosis; (2) genetic analysis performed with a large gene panel; (3) classification of variants following American College of Medical Genetics and Genomics guidelines. Patients with a pathogenic/likely pathogenic variant in SCN5A were defined as SCN5A+. Patients with a reported variant in a non-SCN5A gene or with no reported variants were defined as patients with SCN5A-. All variants were classified as missense or predicted loss of function.RESULTS:A total of 500 BrS patients were analyzed. A total of 104 patients (20.8%) were SCN5A+ and 396 patients (79.2%) were SCN5A-. A non-SCN5A gene variant was found in 75 patients (15.0%), of whom, 58 patients (77.3%) had a missense variant and 17 patients (22.7%) had a predicted loss of function variant. At a follow-up of 84.0 months, 48 patients (9.6%) experienced a ventricular arrhythmia (VA). Patients without any variant had higher VA-free survival, compared with carriers of a predicted loss of function variant in SCN5A+ or non-SCN5A genes. There was no difference in VA-free survival between patients without any variant and missense variant carriers in SCN5A+ or non-SCN5A genes. At Cox analysis, SCN5A+ or non-SCN5A predicted loss of function variant was an independent predictor of VA.CONCLUSIONS:In a large BrS cohort, the yield for SCN5A+ is 20.8%. A predicted loss of function variant carrier is an independent predictor of VA.

BACKGROUND: Brugada syndrome (BrS) is associated with ventricular fibrillation (VF). Different VF mechanisms have been described, and repolarization gradients were associated with VF in a BrS model. The aim of this study is to map VF in BrS with ECG imaging. Furthermore, spatial correlation between sinus rhythm maps and VF maps was evaluated. METHODS: Inclusion criteria were (1) BrS diagnosis and (2) VF mapped with ECG imaging during right ventricle outflow tract ablation. VF mechanism was classified into (1) rotational, (2) focal, and (3) irregular. For comparison, 6 controls were enrolled. The following sinus rhythm maps were performed: activation, recovery time, and activation-recovery interval time. Spatial overlap between steep repolarization gradients (cliffs) at recovery time and activation-recovery interval time maps and initiating VF rotational activity was evaluated with photogrammetry. RESULTS: A total of 28 VF maps in 21 patients with BrS were analyzed. In the first ≈7 seconds of VF, rotational, focal, and irregular mechanisms were found. In 19 patients with BrS (90.5%) and none of the controls, a right ventricle outflow tract repolarization cliff only was found. In all these patients, the singularity point of the first initiating rotational VF activity spatially overlapped with the right ventricle outflow tract cliff. Abolition of right ventricle outflow tract repolarization cliffs was confirmed in all but 2 patients (94.3%). In one patient with recurrence, VF was mapped on the anterior right ventricle over a cliff that was not targeted at the first ablation procedure. CONCLUSIONS: In patients with BrS, repolarization heterogeneity has a critical role in VF. Repolarization cliffs might be a therapeutic target in VF ablation.

BACKGROUND:Brugada syndrome (BrS) has been associated with sudden cardiac death in otherwise healthy subjects, and drug-induced BrS accounts for 55% to 70% of all patients with BrS. This study aims to develop a deep convolutional neural network and evaluate its performance in recognizing and predicting BrS diagnosis. METHODS AND RESULTS:Consecutive patients who underwent ajmaline testing for BrS following a standardized protocol were included. ECG tracings from baseline and during ajmaline were transformed using wavelet analysis and a deep convolutional neural network was separately trained to (1) recognize and (2) predict BrS type I pattern. The resultant networks are referred to as BrS-Net. A total of 1188 patients were included, of which 361 (30.3%) patients developed BrS type I pattern during ajmaline infusion. When trained and evaluated on ECG tracings during ajmaline, BrS-Net recognized a BrS type I pattern with an AUC-ROC of 0.945 (0.921-0.969) and an AUC-PR of 0.892 (0.815-0.939). When trained and evaluated on ECG tracings at baseline, BrS-Net predicted a BrS type I pattern during ajmaline with an AUC-ROC of 0.805 (0.845-0.736) and an AUC-PR of 0.605 (0.460-0.664). CONCLUSIONS:BrS-Net, a deep convolutional neural network, can identify BrS type I pattern with high performance. BrS-Net can predict from baseline ECG the development of a BrS type I pattern after ajmaline with good performance in an unselected population.

Patients with Brugada syndrome (BrS) have an increased risk of arrhythmias, including atrial tachyarrhythmias (ATas).The purpose of this study was to assess underlying atrial cardiomyopathy in BrS and the effect of ajmaline (AJM) test on the atrium of BrS patients using electrocardiogram imaging (ECGI).All consecutive patients diagnosed with BrS in a monocentric registry were screened and included if they met the following criteria: 1) BrS diagnosed following current recommendations; and 2) ECGI map performed before and after AJM with a standard protocol. Consecutive patients with no structural heart disease or BrS who had undergone ECGI were included as a control group. Genetic analysis for SCN5A was performed in all BrS patients. Total atrial conduction time (TACT) and local atrial conduction time (LACT) were calculated from atrial ECGI. The primary endpoint was ATas during follow-up.Forty-three consecutive BrS patients and 40 control patients were included. Both TACT and LACT were significantly prolonged in BrS patients compared with control patients. Furthermore, TACT and LACT were significantly higher after AJM administration and in BrS patients who were carriers of a pathogenic/likely pathogenic SCN5A variant. After a mean follow-up of 40.9 months, 6 patients experienced a first ATa occurrence (all in the BrS group, 13.9%). TACT was the only independent predictor of ATas with a cutoff of >138.5 ms (sensitivity 0.92 [95% CI: 0.83-0.98], specificity 0.70 [95% CI: 0.59-0.81]).ECGI-calculated TACT and LACT are significantly prolonged in BrS patients compared with control patients, and in BrS patients after AJM. This may be consistent with a concealed atrial cardiomyopathy in BrS.

Abstract Aims A pathogenic/likely pathogenic (P/LP) variant in SCN5A is found in 20–25% of patients with Brugada syndrome (BrS). However, the diagnostic yield and prognosis of gene panel testing in paediatric BrS is unclear. The aim of this study is to define the diagnostic yield and outcomes of SCN5A gene testing with ACMG variant classification in paediatric BrS patients compared with adults. Methods and results All consecutive patients diagnosed with BrS, between 1992 and 2022, were prospectively enrolled in the UZ Brussel BrS registry. Inclusion criteria were: (i) BrS diagnosis; (ii) genetic analysis performed with a large gene panel; and (iii) classification of gene variants following ACMG guidelines. Paediatric patients were defined as ≤16 years of age. The primary endpoint was ventricular arrhythmias (VAs). A total of 500 BrS patients were included, with 63 paediatric patients and 437 adult patients. Among children with BrS, 29 patients (46%) had a P/LP variant (P+) in SCN5A and no variants were found in 34 (54%) patients (P−). After a mean follow-up of 125.9 months, 8 children (12.7%) experienced a VA, treated with implanted cardioverter defibrillator shock. At survival analysis, P− paediatric patients had higher VA-free survival during the follow-up, compared with P+ paediatric patients. P+ status was an independent predictor of VA. There was no difference in VA-free survival between paediatric and adult BrS patients for both P− and P+. Conclusion In a large BrS cohort, the diagnostic yield for P/LP variants in the paediatric population is 46%. P+ children with BrS have a worse arrhythmic prognosis.

Drug-induced type I Brugada syndrome (BrS) is associated with a ventricular arrhythmia (VA) rate of 1 case per 100 person-years. This study aims to evaluate changes in electrocardiographic (ECG) parameters such as microvolt T wave alternans (mTWA) and heart rate variability (HRV) at baseline and during ajmaline testing for BrS diagnosis. Consecutive patients diagnosed with BrS during ajmaline testing with 5-year follow-up were included in this study. For comparison, a negative ajmaline control group and an isoproterenol control group were also included. ECG recordings during ajmaline or isoproterenol test were divided in two timeframes from which ECG parameters were calculated: a 5-min baseline timeframe and a 5-min drug timeframe. A total of 308 patients with BrS were included, 22 (0.7

BACKGROUND Patients with Brugada syndrome (BrS) have an increased risk of arrhythmias, including atrial tachyarrhythmias (ATas). OBJECTIVES The purpose of this study was to assess underlying atrial cardiomyopathy in BrS and the effect of ajmaline (AJM) test on the atrium of BrS patients using electrocardiogram imaging (ECGI). METHODS All consecutive patients diagnosed with BrS in a monocentric registry were screened and included if they met the following criteria: 1) BrS diagnosed following current recommendations; and 2) ECGI map performed before and after AJM with a standard protocol. Consecutive patients with no structural heart disease or BrS who had undergone ECGI were included as a control group. Genetic analysis for SCN5A was performed in all BrS patients. Total atrial conduction time (TACT) and local atrial conduction time (LACT) were calculated from atrial ECGI. The primary endpoint was ATas during follow-up. RESULTS Forty-three consecutive BrS patients and 40 control patients were included. Both TACT and LACT were significantly prolonged in BrS patients compared with control patients. Furthermore, TACT and LACT were significantly higher after AJM administration and in BrS patients who were carriers of a pathogenic/likely pathogenic SCN5A variant. After a mean follow-up of 40.9 months, 6 patients experienced a first ATa occurrence (all in the BrS group, 13.9%). TACT was the only independent predictor of ATas with a cutoff of >138.5 ms (sensitivity 0.92 [95% CI: 0.83-0.98], specificity 0.70 [95% CI: 0.59-0.81]). CONCLUSIONS ECGI-calculated TACT and LACT are significantly prolonged in BrS patients compared with control patients, and in BrS patients after AJM. This may be consistent with a concealed atrial cardiomyopathy in BrS. (J Am Coll Cardiol EP 2023;9:2096-2105) (c) 2023 by the American College of Cardiology Foundation.

Abstract Aims Brugada syndrome (BrS) is a hereditary arrhythmic disease, associated with sudden cardiac death. To date, little is known about the psychosocial correlates and impacts associated with this disease. The aim of this study was to assess a set of patient-reported psychosocial outcomes, to better profile these patients, and to propose a tailored psychosocial care. Methods and results Patients were recruited at the European reference Centre for BrS at Universitair Ziekenhuis Brussel, Belgium. Recruitment was undertaken in two phases: phase 1 (retrospective), patients with confirmed BrS, and phase 2 (prospective), patients referred for ajmaline testing who had an either positive or negative diagnosis. BrS patients were compared to controls from the general population. Two hundred and nine questionnaires were analysed (144 retrospective and 65 prospective). Collected patient-reported outcomes were on mental health (12 item General Health Questionnaire; GHQ-12), social support (Oslo Social Support Scale), health-related quality of life, presence of Type-D personality (Type-D Scale; DS14), coping styles (Brief-COPE), and personality dimensions (Ten Item Personality Inventory). Results showed higher mental distress (GHQ-12) in BrS patients (2.53 ± 3.03) than in the general population (P < 0.001) and higher prevalence (32.7%) of Type D personality (P < 0.001) in patients with confirmed Brugada syndrome (BrS +). A strong correlation was found in the BrS + group (0.611, P < 0.001) between DS14 negative affectivity subscale and mental distress (GHQ-12). Conclusion Mental distress and type D personality are significantly more common in BrS patients compared to the general population. This clearly illustrates the necessity to include mental health screening and care as standard for BrS.

Management of ventricular arrhythmias (VAs) beyond implantable cardioverter-defibrillator positioning in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) is challenging. Catheter ablation of the ventricular substrate often requires a combination of endocardial and epicardial approaches, with disappointing outcomes due to the progressive nature of the disease. We report the Universitair Ziekenhuis Brussel experience through a case series of 16 patients with drug-refractory ARVC, who have undergone endocardial and/or epicardial catheter ablation of VAs with a thoracoscopic hybrid-approach. After a mean follow-up time of 5.16 years (SD 2.9 years) from the first hybrid-approach ablation, VA recurrence was observed in 5 patients (31.25%): among these, patients 4 patients (80%) received a previous ablation and 1 of 11 patients (9.09%) who had a hybrid ablation as first approach had a VA recurrence (80% vs 9.09%; logrank p = 0.04). Despite the recurrence rate of arrhythmic events, all patients had a significant reduction in the arrhythmic burden after ablation, with a mean of 4.65 years (SD 2.9 years) of freedom from clinically significant arrhythmias, defined as symptomatic VAs or implantable cardioverter-defibrillator-delivered therapies. In conclusion, our case series confirms that management of VAs in patients with ARVC is difficult because patients do not always respond to antiarrhythmic medications and can require multiple invasive procedures. A multidisciplinary approach involving cardiologists, cardiac surgeons, and cardiac electrophysiologists, together with recent cardiac mapping techniques and ablation tools, might mitigate these difficulties and improve outcomes. (c) 2022 Elsevier Inc. All rights reserved. (Am J Cardiol 2022;181:45-54)

Abstract Funding Acknowledgements Type of funding sources: None. Background Brugada syndrome (BrS) is caused by mutations in SCN5A gene in 15%-20% of cases. Previous studies showed a worse prognosis in SCN5A mutation carriers (SCN5A+). Purpose To evaluate genotype-phenotype correlation with ECG imaging (ECGI). Methods All consecutive patients who underwent ECGI with CardioInsight for BrS were retrospectively analyzed. ECGI parameters analyzed before and after ajmaline administration were: 1) Right ventricular outflow tract (RVOT) activation time (RVOT-AT) and 2) RVOT recovery time (RVOT-RT). Genetic analysis was performed in all patients with SeqCap EZ Human Exome Probes v3.0 for BrS. Patients were defined as SCN5A+ if they had a pathogenic/likely pathogenic mutation in SCN5A following ACMG guidelines. Results Thirty-six BrS patients were included and 8 patients (22%) were SCN5A+. At baseline ECGI map, mean RVOT-RT was higher in SCN5A+ [384.8 ms vs 362 ms, p=0.037], with no difference in RVOT-AT (p=0.65). After ajmaline administration SCN5A+ patients showed higher RVOT-AT [125.6 ms vs 102.4 ms, p=0.045] (Figure) and higher RVOT-RT [426.4 ms vs 400 ms, p=0.038]. At univariate logistic regression, baseline RVOT-RT was a predictor of SCN5A mutation (specificity: 0.64, sensitivity 0.88, AUC 0.75). Conclusion In BrS syndrome SCN5A+ patients exhibit marked depolarization and repolarization abnormalities as assessed by ECGI.

BACKGROUND Brugada syndrome (BrS) is caused by mutations in SCN5A gene in 15%-20% of cases. Previous studies showed worse prognosis in SCN5A mutation carriers (SCN5A+). To date, there are no data on genotype-phenotype correlation with electrocardiographic (ECG) imaging (ECGI) and high-density epicardial electroanatomic map. OBJECTIVE This study aimed to correlate SCN5A mutation with substrate severity in BrS assessed by ECGI and high-density electroanatomic map. METHODS All consecutive BrS patients undergoing ECGI and high-density epicardial electroanatomic map with HD Grid Mapping Catheter were retrospectively analyzed. On ECGI, the following parameters were analyzed before and after ajmaline administration: right ventricular outflow tract (RVOT) activation time (RVOT-AT) and RVOT recovery time (RVOT-RT). On electroanatomic map, the parameters analyzed before and after ajmaline were high-frequency potential activation time (HFPat), high-frequency potential duration (HFPd), high-frequency potential amplitude (HFPa), low-frequency potential activation time (LFPat), low-frequency potential duration (LFPd), and low-frequency potential amplitude (LFPa). RESULTS Thirty-nine BrS patients with ECGI were included. Eight patients (20.5%) were SCN5A+. At baseline ECGI map, mean RVOT-RT was longer in SCN5A+ (P = .024). After ajmaline administration, SCN5A+ patients showed longer RVOT-AT (125.6 vs 100.8 ms; P = .045) and longer RVOT-RT (426.4 vs 397 ms; P = .033). After ajmaline administration, SCN5A+ showed longer HFPat (164.1 vs 119.5 ms; P = .041); longer LFPat (272.7 vs 200.5 ms; P = .018); and longer LFPd (211.9 vs 151.2 ms; P = .033). CONCLUSION In BrS, SCN5A+ patients compared with SCN5A- patients exhibitmarked depolarization and repolarization abnormalities as assessed by ECGI and epicardial high-density electroanatomic map.

Myotonia congenita is a rare neuromuscular disorder caused by CLCN1 mutations resulting in delayed muscle relaxation. Extramuscular manifestations are not considered to be present in chloride skeletal channelopathies, although recently some cardiac manifestations have been described. We report a family with autosomal dominant myotonia congenita and Brugada syndrome. Bearing in mind the previously reported cases of cardiac arrhythmias in myotonia congenita patients, we discuss the possible involvement of the CLCN1-gene mutations in primary cardiac arrhythmia.