Electrophysiological Study Prognostic Value and Long-Term Outcome in Drug-Induced Type 1 Brugada Syndrome: The IBRYD Study

Prognostic significance of electrophysiological study in drug-induced type-1 Brugada syndrome: a brief systematic review

BACKGROUND

Risk stratification in drug-induced type-1 Brugada syndrome (BrS) patients is challenging. The role of electrophysiological study (EPS) is debated as the majority of drug-induced type-1 BrS patients would not be studied according to the latest recommendations.

METHODS

A complete systematic literature search was performed to gauge the EPS role in this population. Three subgroups were defined: positive-EPS group, negative-EPS group, no-EPS group.

RESULTS

Among 1318 drug-induced type-1 BrS patients, no significant difference in the incidence rate of arrhythmic events was observed between groups (I2 = 45%, P for subgroup difference = 0.10) during a mean follow-up of 5.1 years, also considering symptomatic status.

CONCLUSION

In long-term follow-up of drug-induced type-1 BrS patients, EPS does not seem to aid prognostic stratification.

Long-term clinical outcomes of patients with drug-induced type 1 Brugada electrocardiographic pattern: A nationwide cohort registry study

BACKGROUND

There are limited real-world data on the extended prognosis of patients with drug-induced type 1 Brugada electrocardiogram (ECG).

OBJECTIVE

We assessed the clinical outcomes and predictors of life-threatening arrhythmias in patients with drug-induced type 1 Brugada ECG.

METHODS

This multicenter retrospective study, conducted at 21 Italian and Swiss hospitals from July 1997 to May 2021, included consecutive patients with drug-induced type 1 ECG. The primary outcome, a composite of appropriate ICD therapies and sudden cardiac death, was assessed along with the clinical predictors of these events.

RESULTS

A total of 606 patients (mean age 49.7 ± 14.7 years; 423 [69.8%] men) were followed for a median of 60.3 months (interquartile range 23.0-122.4 months). Nineteen patients (3.1%) experienced life-threatening arrhythmias, with a median annual event rate of 0.5% over 5 years and 0.25% over 10 years. The SCN5A mutation was the only predictor of the primary outcome (hazard ratio 4.54; P = .002), whereas a trend was observed for unexplained syncope (hazard ratio 3.85; P = .05). In patients who were asymptomatic at presentation, the median annual rate of life-threatening arrhythmias is 0.24% over 5 years and increases to 1.2% if they have inducible ventricular fibrillation during programmed ventricular stimulation.

CONCLUSION

In patients with drug-induced type 1 Brugada ECG, the annual risk of life-threatening arrhythmias is low, with the SCN5A mutation as the only independent predictor. Unexplained syncope correlated with worse clinical outcomes. Ventricular fibrillation inducibility at programmed ventricular stimulation significantly increases the median annual rate of life-threatening arrhythmias from 0.24% to 1.2% over 5 years.

The Subcutaneous Implantable Cardioverter-Defibrillator: A Patient Perspective

The subcutaneous implantable cardioverter-defibrillator (S-ICD) is a new technology for the management of ICD patients. But what is the patients' perspective? Previous studies on the transvenous ICD (TV-ICD) showed that device implantation is related not only to anxiety and depression because of the fear of ICD shocks, but also to many biopsychosocial factors like body image changes, perceived reduction of socialization and limitation in professional and sports activities. Anxiety and distress are more evident in younger women because of aesthetic reasons. The scar size and the position of the S-ICD can help these patients and positively influence their social relationships. Moreover, the position of the S-ICD reduces possible complications from catheters due to stress injury and can improve patients' professional life by avoiding some work activity limitations. An S-ICD can be also a good option for athletes in avoiding subclavian crash and reducing inappropriate shocks. However, some questions remain unsolved because an S-ICD is not suitable for patients with indications for pacing, cardiac resynchronization therapy or anti-tachycardia pacing. In conclusion, the use of an S-ICD can assist physicians in reducing the negative impact of implantation on the well-being of some groups of patients by helping them to avoid depression and anxiety as well as improving their noncompliance with their medical treatment.

Case report: State-of-the-art risk-modifying treatment of sudden cardiac death in an asymptomatic patient with a mutation in the SCN5A gene and a review of the literature

Brugada syndrome is a rare hereditary disorder characterized by distinct ECG findings, complex genetics, and a high risk of sudden cardiac death. Recognition of the syndrome is crucial as it represents a paradigm of sudden death tragedy in individuals at the peak of their lives. Notably, Brugada syndrome accounts for more than 20% of sudden cardiac deaths in individuals with structurally normal hearts. Although this syndrome follows an autosomal dominant inheritance pattern, it is more prevalent and severe in males. Diagnosis is primarily based on the characteristic ECG pattern observed in the right precordial leads. Mutations in the SCN5A gene, resulting in loss of function, are the most common genetic cause. We presented a 36-year-old proband with a family history of sudden cardiac death. Although the patient was asymptomatic for Brugada syndrome, his father had experienced sudden death at the age of 36. The proband was admitted to St. Catherine's Specialty Hospital where blood was taken and subjected to next-generation sequencing (NGS) using a "Sudden cardiac death" panel. The analysis identified a pathogenic variant in the SCN5A gene [c.4222G > A(p.Gly1408Arg)], which is associated with autosomal dominant Brugada syndrome. Based on the positive genetic test result, the patient was referred for further examination. ECG with modified precordial lead positioning confirmed the presence of the Brugada phenotype, displaying the type-2 and type-1 ECG patterns. Therefore, we made the diagnosis and decided to implant an implantable cardioverter-defibrillator (ICD) based on the results of broad genetic NGS testing, diagnostic criteria (ECG), and considering the high burden of sudden cardiac death in the patient's family, as well as his concerns that limited his everyday activities. This case shows that genetics and personalized medicine hold immense potential in the primary prevention, diagnosis, and treatment of Brugada syndrome and sudden cardiac death.

Electroanatomic mapping in athletes: Why and when. An expert opinion paper from the Italian society of sports cardiology

Three-dimensional electroanatomical mapping (EAM) has the potential to identify the pathological substrate underlying ventricular arrhythmias (VAs) in different clinical settings by detecting myocardial areas with abnormally low voltages, which reflect the presence of different cardiomyopathic substrates. In athletes, the added value of EAM may be to enhance the efficacy of third-level diagnostic tests and cardiac magnetic resonance (CMR) in detecting concealed arrhythmogenic cardiomyopathies. Additional benefits of EAM in the athlete include the potential impact on disease risk stratification and the consequent implications for eligibility to competitive sports. This opinion paper of the Italian Society of Sports Cardiology aims to guide general sports medicine physicians and cardiologists on the clinical decision when to eventually perform an EAM study in the athlete, highlighting strengths and weaknesses for each cardiovascular disease at risk of sudden cardiac death during sport. The importance of early (preclinical) diagnosis to prevent the negative effects of exercise on phenotypic expression, disease progression, and worsening of the arrhythmogenic substrate is also addressed.

Opportunities and drawbacks of the subcutaneous defibrillator across different clinical settings

INTRODUCTION

The subcutaneous implantable cardioverter-defibrillator (S-ICD) is an established therapy for the prevention of sudden cardiac death (SCD) and an alternative to a transvenous implantable cardioverter-defibrillator system in selected patients. Beyond randomized clinical trials, many observational studies have described the clinical performance of S-ICD across different subgroups of patients.

AREAS COVERED

Our review aimed to describe the opportunities and drawbacks of the S-ICD, focusing on their use in special populations and across different clinical settings.

EXPERT OPINION

The choice to implant S-ICD should be based on the patient's tailored approach, which takes into account the adequate S-ICD screening at rest or during stress, the infective risk, the ventricular arrhythmia susceptibility, the progressive nature of the underlying disease, the work or sports activity, and the risk of lead-related complications.

Heart rate variability and microvolt T wave alternans changes during ajmaline test may predict prognosis in Brugada syndrome

PURPOSE

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.

METHODS

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.

RESULTS

A total of 308 patients with BrS were included, 22 (0.7%) of which suffered VAs during follow-up. One hundred patients were included in both isoproterenol and negative ajmaline control groups. At baseline, there was no difference in ECG parameters between control groups and patients with BrS, nor between BrS with and without VAs. During ajmaline testing, BrS with VAs presented longer QRS duration [159 ± 34 ms versus 138 (122-155) ms, p = 0.006], higher maximum mTWA [33.8 (14.0-114) µV versus 8.00 (3.67-28.2) µV, p = 0.001], and lower power in low frequency band [25.6 (5.8-53.8) ms² versus 129.5 (52.7-286) ms², p < 0.0001] when compared to BrS without VAs.

CONCLUSIONS

Ajmaline induced important HRV changes similar to those observed during isoproterenol. Increased mTWA was observed only in patients with BrS. BrS with VAs during follow-up presented worse changes during ajmaline test, including lower LF power and higher maximum mTWA which were independent predictors of events.

Lights and shadows of subcutaneous implantable cardioverter-defibrillator in Brugada syndrome

Currently the cornerstone of therapy for ventricular arrhythmic complications and sudden cardiac death prevention in Brugada syndrome (BrS) is an implantable cardioverter-defibrillator (ICD). BrS patient population differs from the majority of patients with an ICD implanted for structural heart disease, and as widely known, transvenous ICD (TV-ICD) systems have been associated with high complication rates in patients with BrS. Technological evolution of these devices has certainly reduced complications due to the device itself, but a careful preimplant screening of these patients is still essential. To date, criteria for an adequate screening process to select suitable candidates for a subcutaneous implantable cardioverter-defibrillator (S-ICD) from patients with BrS are sometimes nonstandardized and often lack important precautions that are instead fundamental to select the most suitable type of ICD for these patients. To better select suitable candidates for an S-ICD from patients with BrS, a full screening process should include screening during or immediately after an exercise test and after a drug provocation challenge test. We report an analysis of the "lights and shadows" of S-ICD for a correct use of this device in patients with BrS.

Case report: Lamin A/C gene mutation in patient with drug-induced type 1 Brugada syndrome at high arrhythmic risk

We report the case of drug-induced type 1 Brugada syndrome at high arrhythmic risk associated with Lamin A/C gene mutation.

Subcutaneous versus transvenous implantable cardioverter-defibrillator among drug-induced type-1 ECG pattern Brugada syndrome: a propensity score matching analysis from IBRYD study

No real-world data are available about the complications rate in drug-induced type 1 Brugada Syndrome (BrS) patients with an implantable cardioverter-defibrillator (ICD). Aim of our study is to compare the device-related complications, infections, and inappropriate therapies among drug-induced type 1 BrS patients with transvenous- ICD (TV-ICD) versus subcutaneous-ICD (S-ICD). Data for this study were sourced from the IBRYD (Italian BRugada sYnDrome) registry which includes 619 drug-induced type-1 BrS patients followed at 20 Italian tertiary referral hospitals. For the present analysis, we selected 258 consecutive BrS patients implanted with ICD. 198 patients (76.7%) received a TV-ICD, while 60 a S-ICD (23.4%). And were followed-up for a median time of 84.3 [46.5-147] months. ICD inappropriate therapies were experienced by 16 patients (6.2%). 14 patients (7.1%) in the TVICD group and 2 patients (3.3%) in S-ICD group (log-rank P = 0.64). ICD-related complications occurred in 31 patients (12%); 29 (14.6%) in TV-ICD group and 2 (3.3%) in S-ICD group (log-rank P = 0.41). ICD-related infections occurred in 10 patients (3.88%); 9 (4.5%) in TV-ICD group and 1 (1.8%) in S-ICD group (log-rank P = 0.80). After balancing for potential confounders using the propensity score matching technique, no differences were found in terms of clinical outcomes between the two groups. In a real-world setting of drug-induced type-1 BrS patients with ICD, no significant differences in inappropriate ICD therapies, device-related complications, and infections were shown among S-ICD vs TV-ICD. However, a reduction in lead-related complications was observed in the S-ICD group. In conclusion, our evidence suggests that S-ICD is at least non-inferior to TV-ICD in this population and may also reduce the risk of lead-related complications which can expose the patients to the necessity of lead extractions.

Electrocardiographic variables associated with underlying Brugada syndrome or drug-induced Type 1 Brugada pattern in patients with slow/fast atrioventricular nodal reentrant tachycardia

Background

The coexistence of clinical atrioventricular nodal reentrant tachycardia (AVNRT) and drug-induced type 1 Brugada pattern (DI-Type 1 BrP) has been previously reported. The present study was designed to determine the 12-lead ECG characteristics at baseline and during AVNRT and to identify a subset of 12-lead ECG variables of benefit associated with underlying Brugada syndrome (BrS)/DI-Type 1 BrP among patients with slow/fast AVNRT.

Methods

A total of 40 (11 numerical/29 categorical) 12-lead ECG parameters were analyzed and compared between patients with (n = 69) and without (n = 104) BrS/DI-Type1-BrP matched for age, female gender, body mass index, left ventricular ejection fraction and comorbid conditions. Five distinct types of ECG pattern (Type A/B/C/D/E) in V1-V2 leads during AVNRT were defined.

Results

A total of nine electrocardiographic variables, four at baseline, and five during AVNRT were identified. At baseline, patients with BrS/DI-Type 1 BrP had higher prevalence of interatrial block, leftward shift of frontal plane QRS axis, the absence of normal QRS pattern (the presence of rSr' pattern or type 2/3 Brugada pattern) in V1-V2 and QRS fragmentation in inferior leads compared to patients without BrS/DI-Type 1 BrP. During AVNRT, patients with BrS/DI-Type 1 BrP had higher prevalence of Type A ECG pattern ("coved-type" ST-segment elevation) in V1-V2, Type C ECG pattern (pseudo-r' deflection in V1 and "RBBB-like" pattern in V2), pseudo-r' deflection in V1, QRS fragmentation in inferior leads and "isolated" QRS fragmentation/notching/slurring in aVL compared to patients without BrS/DI-Type 1 BrP.

Conclusions

We identify several electrocardiographic variables that point to an underlying type 1 BrP among patients with slow/fast AVNRT.

Device-Related Complications and Inappropriate Therapies Among Subcutaneous vs. Transvenous Implantable Defibrillator Recipients: Insight Monaldi Rhythm Registry

Introduction

In the context of randomized clinical trials, subcutaneous implantable cardiac defibrillators (S-ICDs) are non-inferior to transvenous ICDs (T-ICDs) concerning device-related complications or inappropriate shocks in patients with an indication for defibrillator therapy and not in need of pacing. We aimed at describing the clinical features of patients who underwent S-ICD implantation in our clinical practice, as well as the ICD-related complications and the inappropriate therapies among S-ICD vs. T-ICD recipients during a long-term follow-up.

Materials and Methods

All patients undergoing ICD, both S-ICD and TV-ICD, at Monaldi Hospital from January 1, 2015 to January 1, 2019 and followed up at our institution were included in the present analysis. The clinical variables associated with S-ICD implantation were evaluated by logistic regression analyses. We collected the ICD inappropriate therapies, ICD-related complications (including both pulse generator and lead-related complications), ICD-related infections, appropriate ICD therapies, and overall mortality. Kaplan-Meier (KM) analyses were performed to assess the risk of clinical outcome events between the two subgroups. A time-dependent Cox regression analysis was performed to adjust the results.

Results

Total 607 consecutive patients (mean age 53.8 ± 16.8, male 77.8%) with both TV-ICD (n: 290, 47.8%) and S-ICD (n: 317, 52.2%), implanted and followed at our center for a mean follow-up of 1614 ± 1018 days, were included in the study. At multivariate logistic regression analysis, an independent association between S-ICD implantation and ionic channel disease [OR: 6.01 (2.26–15.87); p < 0.0001] and ischemic cardiomyopathy [OR: 0.20 (0.12–0.35); p < 0.0001] was shown. The KM analysis did not show a significantly different risk of the inappropriate ICD therapies (log rank p = 0.64) between the two subgroups; conversely, a significant increase in the risk of ICD-related complications (log rank p = 0.02) and infections (log rank p = 0.02) in TV-ICD group was shown. The adjusted risk for ICD-related infections [OR: 0.07 (0.009–0.55), p = 0.01] and complications [0.31 (0.12–0.81), p = 0.01] was significantly lower among patients with S-ICD.

Conclusions

The choice to implant S-ICD was mainly driven by younger age and the presence of ionic channel disease; conversely ischemic cardiomyopathy reduces the probability to use this technology. No significant differences in inappropriate ICD therapies were shown among S-ICD vs. TV-ICD group; moreover, S-ICD is characterized by a lower rate of infectious and non-infectious complications leading to surgical revision or extraction.

Ajmaline-Induced Abnormalities in Brugada Syndrome: Evaluation With ECG Imaging

Background The rate of sudden cardiac death (SCD) in Brugada syndrome (BrS) is ≈1%/y. Noninvasive electrocardiographic imaging is a noninvasive mapping system that has a role in assessing BrS depolarization and repolarization abnormalities. This study aimed to analyze electrocardiographic imaging parameters during ajmaline test (AJT). Methods and Results All consecutive epicardial maps of the right ventricle outflow tract (RVOT-EPI) in BrS with CardioInsight were retrospectively analyzed. (1) RVOT-EPI activation time (RVOT-AT); (2) RVOT-EPI recovery time, and (3) RVOT-EPI activation-recovery interval (RVOT-ARI) were calculated. ∆RVOT-AT, ∆RVOT-EPI recovery time, and ∆RVOT-ARI were defined as the difference in parameters before and after AJT. SCD-BrS patients were defined as individuals presenting a history of aborted SCD. Thirty-nine patients with BrS were retrospectively analyzed and 12 patients (30.8%) were SCD-BrS. After AJT, an increase in both RVOT-AT [105.9 milliseconds versus 65.8 milliseconds, P<0.001] and RVOT-EPI recovery time [403.4 milliseconds versus 365.7 milliseconds, P<0.001] was observed. No changes occurred in RVOT-ARI [297.5 milliseconds versus 299.9 milliseconds, P=0.7]. Before AJT no differences were observed between SCD-BrS and non SCD-BrS in RVOT-AT, RVOT-EPI recovery time, and RVOT-ARI (P=0.9, P=0.91, P=0.86, respectively). Following AJT, SCD-BrS patients showed higher RVOT-AT, higher ∆RVOT-AT, lower RVOT-ARI, and lower ∆RVOT-ARI (P<0.001, P<0.001, P=0.007, P=0.002, respectively). At the univariate logistic regression, predictors of SCD-BrS were the following: RVOT-AT after AJT (specificity: 0.74, sensitivity 1.00, area under the curve 0.92); ∆RVOT-AT (specificity: 0.74, sensitivity 0.92, area under the curve 0.86); RVOT-ARI after AJT (specificity 0.96, sensitivity 0.58, area under the curve 0.79), and ∆RVOT-ARI (specificity 0.85, sensitivity 0.67, area under the curve 0.76). Conclusions Noninvasive electrocardiographic imaging can be useful in evaluating the results of AJT in BrS.