Brugada Syndrome

Abstract

# Reproducibility of the signal-averaged ECG in a family screened for Brugada syndrome {#article-title-2} Introduction This study represents a methodological evaluation of reproducibility of the Signal Averaged-ECG (SAECG) in Brugada syndrome (BS), and is a starting point for a project that aims to evaluate the usefulness of this technique in this particular clinical context. Methods Thirty-six subjects (55.6% women) of the same family, without structural heart disease, mean age 33.86 + 11.35 years, referred for screening of BS, underwent SAECG (with time domain analysis) on two occasions (6-month interval). Late potentials were defined when at least two of three criteria were found: fQRS >114 ms; RMS40 38 ms. All participants were genetically screened and 20 (55.6%) had the mutation (G+). Results The reliability of the SAECG was very good ( k = 0.88, P  < 0.001), with an ICC = 0.89 ( P < 0.001). Fourteen subjects had positive SAECG (10 were G +), two of which changed diagnosis from one to the other time. Strong correlations were found for fQRS, RMS40, and LAD ( R = 0.79, 0.78, and 0.81, respectively). The RMS40 and LAS parameters were the most consistent in both moments ( k = 0.77 and 0.66, respectively, P < 0.001). Good indicators of reproducibility were also extracted in the Bland–Altman analysis. The mean discrepancy was 0.42 + 7.79 ms, −2.97 + 11.63, and 1.56 + 8.80 mV, respectively, for fQRS, RMS40, and LAS, without significant differences between G+ and G−. Conclusion Our data illustrate a high reproducibility of the SAECG, documented by excellent correlations and small discrepancies in the estimated parameters, particularly in patients with confirmed BS. # Cardiac event rate in Brugada patients {#article-title-3} Background ICD implantation can prevent sudden cardiac death (SCD) in Brugada patients. However, selecting patients to receive an ICD for primary prevention is challenging. ICD implantation also carries some risks, including inappropriate shock. The aims of this study were: Method Retrospective analysis from the registry of 29 ICD implantations for Brugada patients over the past 10 years in IJN, categorized into 3 groups of patients: 1. Asymptomatic (n = 6), 2. Syncope (n = 11), and 3. Those with documented VT/VF or survivors of resuscitated SCD (n = 12). Results During mean follow up time 53 months (min: 4 months, max: 161 months), none of group 1 developed cardiac event, 1 patient in group 2 (9%) developed VF and got appropriate shock, 10 patients in the documented VT/VF or resuscitated group (83.3%) had VF and appropriate shock. 1 patient in the asymptomatic group had inappropriate shock. Conclusion Although the number of patients is small (but with good duration of follow up), this study demonstrated that the risk of SCD is low in asymptomatic Brugada patients. This will help physicians to stratify Brugada patients better. # Value of C-reactive protein in patients with asymptomatic and symptomatic Brugada syndrome {#article-title-4} Background Brugada syndrome (BrS) is an arrhythmogenic disease with potential lethal outcomes. Inflammation in BrS and its clinical implication are unknown. We assessed the relationship between inflammation and arrhythmic events in BrS. Methods and results Fifty-four patients with BrS underwent work up. All had blood samples drawn for C-reactive protein levels at admission, prior to any invasive intervention. The decision to place an ICD was based on standard guidelines and was independent of C-reactive protein concentrations. Patients with conditions associated with increase of C-reactive protein levels were excluded. We divided our sample in two groups: asymptomatic and symptomatic (syncope or aborted sudden death). In a multivariable analysis, we adjusted for significant variables (age, history of VT, C-reactive protein, 2 mg/L). The mean age was 45 ± 13 years, and 91% was male. Twenty (37%) were symptomatic (17 syncope and 3 aborted SCD). Baseline characteristics were similar in both groups. Mean C-reactive protein level was 1.4 ± 0.9 mg/L in asymptomatic group and 2.4 ± 1.4 mg/L in symptomatic group ( P = 0.003). We hypothesized that C-reactive protein 0 ≥ 2 mg/L may discriminate individuals with and without symptoms. This hypothesis was confirmed by the finding that symptoms were more frequent in the subgroup with C-reactive protein 0 ≥ 2 mg/L ( P = 0.039, 95% CI: 1.07–18.79). In the multivariate model, C-reactive protein concentrations 0 ≥ 2 mg/L remained an independent marker for being symptomatic ( P = 0.018; 95% CI: 1.3–19.3). Conclusion C-reactive protein concentrations ≥2 mg/L appears to be associated with arrhythmic events in patients with BrS and can be considered as a new marker for risk stratification. # A 10-year single-centre prospective study on asymptomatic patients with spontaneous Cove type (Type I) Brugada ECG pattern {#article-title-5} Background Brugada syndrome is a genetic disease characterized by distinct electrocardiogram (ST-segment elevation in leads V1 through V3) finding with an increase in risk of sudden cardiac death. Various risk factors such as syncope, specific ECG pattern, and positive electrophysiology had been identified to predict further VF episodes. Although ICD is a well-proven effective measure for preventing sudden cardiac death in Brugada syndrome, it is often a difficult decision for physician on who is required and benefit. Objective To acquire demographic data, clinical characteristic, follow-up data and clinical outcome of asymptomatic patients with spontaneous Cove type (type I) Brugada ECG pattern. Methods This is a prospective single-centre study. Asymptomatic (without history of syncope, not sudden cardiac death survivor) patient with a coved-type Brugada ECG pattern is recruited since 1999. Demographic data, clinical characteristic, ECG data, investigation, treatment, and clinical outcome were collected. Results There are total 33 patients (31 males and 2 females) recruited since August 1999 to June 2010. The average age is 54.9 years old at diagnosis. Nineteen patients had electrophysiology test done; of which, 7 showed inducible VF. Four patients had ICD implanted eventually. During a total of 178 patient-years follow-up time, there are no documented VF episodes or confirmed sudden cardiac death. Three patients died because of unrelated disease. Conclusion Asymptomatic patients (without history of syncope) with spontaneously Cove type (Type I) Brugada ECG appears to be low risk subgroups in our cohort study. # Follow-up of five patients with Brugada syndrome treated with ICD {#article-title-6} Objective To investigate clinical symptoms, episodes of arrhythmias and its therapy in patients with Brugada syndrome treated with implantable cardioverter-defibrillator (ICD). Methods Five patients with concealed Brugada syndrome (all male, mean age 41.6 ± 10.14 years) were treated with single-chamber ICD and followed up every 3 months. The time of onset, type of arrhythmia, treatments, and its results of the episodes were investigated according to the datalogs of the ICD. Results The diagnosis of Brugada syndrome was made according to sodium-channel blocker provocation test in four patients (two by ajmaline, two by propafenone), and screen of new precordial leads system in another case. Episodes of syncope in all patients and ventricular fibrillation (Vf) in four cases were documented before ICD therapy. During electrophysiological study, ventricular fibrillation could be induced in three patients. During a follow-up of 22 ± 18 months, 75 episodes of Vf were documented, 61 were terminated by 86 shocks successfully, 14 stopped spontaneously. One patient still experienced four episodes of syncope because of his increased defibrillation threshold. One patient had 26 times inappropriate shocks due to atrial fibrillation, which disappeared after we adjusted the protocol of the ICD. Another one had two episodes of syncope though no event was recorded in his ICD. Because the tilt test reached a positive result, the diagnosis of vasovagal syncope was made. Conclusion ICD implantation is a necessary and effective therapy for high-risk patients with Brugada syndrome, and should be followed up regularly and programmed appropriately because of the increased defibrillation threshold or inappropriate shocks.