Severe hypothyroidism as a trigger for Brugada-type ECG abnormalities: a case report and literature review.

Brugada syndrome (BrS) is an inherited disorder that can cause ventricular fibrillation and sudden cardiac death in individuals with otherwise structurally normal hearts. Several provoking factors are known to potentially unmask or exacerbate a typical Brugada ECG pattern in predisposed subjects. Hypothyroidism has been suggested as one of these triggers, but the exact mechanisms underlying this relationship remain poorly understood. Moreover, the severity of thyroid dysfunction beyond which a Brugada-type ECG alteration might be triggered is still unclear. We report the case of a 33-year-old male who displayed a Brugada type 1 ECG pattern and was diagnosed with severe hypothyroidism (TSH > 100 mU/L with undetectable levels of fT4 and fT3). Hormonal replacement therapy with levothyroxine was initiated at increasing doses; serial biochemical and ECG controls were performed, initially every 3 weeks up to 15 weeks and afterward every 3 months. The regression of typical Brugada ECG waveforms could be seen at an early stage, when the patient was still taking a low dose of levothyroxine (37.5 µg/day, i.e., one-fourth of his final requirements of 150 µg/day), and laboratory tests still showed a marked alteration of thyroid hormonal parameters. Hypothyroidism may act as a trigger for Brugada-type ECG abnormalities, but a very severe alteration of the hormonal parameters is necessary to prompt these alterations. In our case, the initiation of replacement therapy with levothyroxine rapidly reversed the ECG modifications, even at a low subtherapeutic dose.

The relevance of electrocardiogram filtering in the differential diagnosis of Brugada syndrome: An illustrative case report.

We present a clinical case of a teenager in whom a Brugada syndrome electrical pattern was found which was finally diagnosed as a Brugada phenocopy due to a wrong setup of the high-pass filter on the electrocardiogram.

Syncope after COVID-19 Vaccination in a Young Man with Unmasking Brugada Syndrome.

A 23-year-old man with no significant medical history was rushed to a hospital due to transient loss of consciousness with incontinence. The patient had developed a fever after his second dose of coronavirus disease 2019 (COVID-19) vaccine, and the patient was found groaning in bed approximately 40 hours after the vaccination in the early morning. The patient was diagnosed with Brugada syndrome (BrS) based on a drug-provocation test. His father had been diagnosed with BrS and died suddenly at 51 years of age. Young adults with a family history of BrS should be cautioned about fever following COVID-19 vaccination.

Clinical characteristics and electrophysiologic properties of SCN5A variants in fever-induced Brugada syndrome.

BACKGROUND: Brugada syndrome (BrS) is a severe inherited arrhythmia syndrome that can be unmasked by fever. METHODS: A multicentre clinical analysis was performed in 261 patients diagnosed with fever-induced BrS, including 198 (75.9%) and 27 (10.3%) patients who received next-generation genetic sequencing and epicardial arrhythmogenic substrate (AS) mapping, respectively. FINDINGS: In fever-induced BrS patients, pathogenic or likely pathogenic (P/LP) SCN5A variant carriers developed fever-induced BrS at a younger age, and more often in females and those of Caucasian descent. They exhibited significant electrophysical abnormalities, including a larger epicardial AS area, and more prolonged abnormal epicardial electrograms. During a median follow-up of 50.5 months (quartiles 32.5-81.5 months) after the diagnosis, major cardiac events (MCE) occurred in 27 (14.4%) patients. Patients with P/LP SCN5A variants had a higher ratio of MCE compared with the rest. Additionally, history of syncope, QRS duration, and Tpe interval could also predict an increased risk for future MCE according to univariate analysis. Multivariate analysis indicated that only P/LP SCN5A variants were independent significant predictors of MCE. Computational structural modelling showed that most variants are destabilizing, suggesting that Nav1.5 structure destabilization caused by SCN5A missense variants may contribute to fever-induced BrS. INTERPRETATION: In our cohort, P/LP SCN5A variant carriers with fever-induced BrS are more prevalent among patients of Caucasian descent, females, and younger patients. These patients exhibit aggressive electrophysiological abnormalities and worse outcome, which warrants closer monitoring and more urgent management of fever. FUNDING: The current work was supported by the National Natural Science Foundation Project of China (Nos. 82270332 & 81670304), The Fundamental Research Funds for the Central Universities of China - Independent Research Project of Wuhan University (No. 2042022kf1217) from China; the National Institutes of Health of USA [NIH R56 (HL47678), NIH R01 (HL138103), and NIH R01 (HL152201)], the W. W. Smith Charitable Trust and the Wistar and Martha Morris Fund, Sharpe-Strumia Research Foundation, the American Heart Association Postdoctoral Fellowship (20POST35220002) from United States; the Netherlands CardioVascular Research Initiative: the Dutch Heart Foundation, Dutch Federation of University Medical Centers, the Netherlands Organization for Health Research and Development, and the Royal Netherlands Academy of Sciences (PREDICT2) from the Netherlands.

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.

Brugada Syndrome Unmasked by Cellulitis of the Face.

A 35-year-old male patient with no specific history visited an emergency medical center with a chief complaint of facial swelling accompanied by fever (38.3°C). Contrast-enhanced facial computed tomography confirmed diffuse soft tissue swelling and facial infiltration of inflammation. Additional laboratory findings revealed elevated white blood cell count and C-reactive protein level. The patient also complained of chest pain; therefore, electrocardiography was performed, which confirmed a curved pattern-like ST-segment elevation (≥2 mm) of V2 without elevated cardiac enzyme levels. Based on various test results, the patient was diagnosed with Brugada syndrome. He was administered intravenous empirical antibiotics and intravenous ibuprofen as an antipyretic for the treatment of facial cellulitis and Brugada syndrome. After the resolution of the symptoms, his body temperature normalized. A subsequent electrocardiogram confirmed a normal sinus rhythm pattern. This case report shows that Brugada syndrome, a rare but life-threatening disease, can be unmasked by facial cellulitis. Because antipyretics can immediately reduce the critical rate of sudden cardiac death, Brugada syndrome should be differentially diagnosed, with an evaluation of facial cellulitis, to prevent sudden cardiac death.

COVID-19 Vaccination-Induced Ventricular Fibrillation in an Afebrile Patient With Brugada Syndrome.

A 43-year-old man presented with cardiac arrest 2 days after the second coronavirus disease 2019 (COVID-19) vaccination with an mRNA vaccine. Electrocardiograms showed ventricular fibrillation and type 1 Brugada pattern ST segment elevation. The patient reported having no symptoms, including febrile sensation. There were no known underlying cardiac diseases to explain such electrocardiographic abnormalities. ST segment elevation completely disappeared in two weeks. Although there were no genetic mutations or personal or family history typical of Brugada syndrome, flecainide administration induced type 1 Brugada pattern ST segment elevation. This case suggests that COVID-19 vaccination may induce cardiac ion channel dysfunction and cause life threatening ventricular arrhythmias in specific patients with Brugada syndrome.

Fibrosis and Conduction Abnormalities as Basis for Overlap of Brugada Syndrome and Early Repolarization Syndrome.

Brugada syndrome and early repolarization syndrome are both classified as J-wave syndromes, with a similar mechanism of arrhythmogenesis and with the same basis for genesis of the characteristic electrocardiographic features. The Brugada syndrome is now considered a conduction disorder based on subtle structural abnormalities in the right ventricular outflow tract. Recent evidence suggests structural substrate in patients with the early repolarization syndrome as well. We propose a unifying mechanism based on these structural abnormalities explaining both arrhythmogenesis and the electrocardiographic changes. In addition, we speculate that, with increasing technical advances in imaging techniques and their spatial resolution, these syndromes will be reclassified as structural heart diseases or cardiomyopathies.

Evaluation of Concordance Between Original Death Certifications and an Expert Panel Process in the Determination of Sudden Unexplained Death in Childhood.

Importance: The true incidence of sudden unexplained death in childhood (SUDC), already the fifth leading category of death among toddlers by current US Centers for Disease Control and Prevention estimates, is potentially veiled by the varied certification processes by medicolegal investigative offices across the United States. Objective: To evaluate the frequency of SUDC incidence, understand its epidemiology, and assess the consistency of death certification among medical examiner and coroner offices in the US death investigation system. Design, Setting, and Participants: In this case series, 2 of 13 forensic pathologists (FPs) conducted masked reviews of 100 cases enrolled in the SUDC Registry and Research Collaborative (SUDCRRC). Children who died aged 11 months to 18 years from 36 US states, Canada, and the United Kingdom had been posthumously enrolled in the SUDCRRC by family members from 2014 to 2017. Comprehensive data from medicolegal investigative offices, clinical offices, and family members were reviewed. Data analysis was conducted from December 2014 to June 2020. Main Outcomes and Measures: Certified cause of death (COD) characterized as explained (accidental or natural) or unexplained, as determined by SUDCRRC masked review process. Results: In this study of 100 cases of SUDC (mean [SD] age, 32.1 [31.8] months; 58 [58.0%] boys; 82 [82.0%] White children; 92 [92.0%] from the United States), the original pathologist certified 43 cases (43.0%) as explained COD and 57 (57.0%) as unexplained COD. The SUDCRRC review process led to the following certifications: 16 (16.0%) were explained, 7 (7.0%) were undetermined because of insufficient data, and 77 (77.0%) were unexplained. Experts disagreed with the original COD in 40 cases (40.0%). These data suggest that SUDC incidence is higher than the current Centers for Disease Control and Prevention estimate (ie, 392 deaths in 2018). Conclusions and Relevance: To our knowledge, this is the first comprehensive masked forensic pathology review process of sudden unexpected pediatric deaths, and it suggests that SUDC may often go unrecognized in US death investigations. Some unexpected pediatric deaths may be erroneously attributed to a natural or accidental COD, negatively affecting surveillance, research, public health funding, and medical care of surviving family members. To further address the challenges of accurate and consistent death certification in SUDC, future studies are warranted.

Pathogenesis and management of Brugada syndrome in schizophrenia: A scoping review.

CONTEXT: Excess cardiovascular morbidity and an increased prevalence of sudden cardiac death (SCD) contributes to premature mortality in schizophrenia. Brugada syndrome (BrS) is an important but underrecognized cause of SCD. It is more commonly seen in schizophrenia than in general population controls. METHODS: We conducted a scoping review to describe the pathogenesis of BrS in schizophrenia and to identify the psychotropic medications that increase the risk of unmasking BrS and associated ventricular arrhythmias resulting in SCD. FINDINGS: Schizophrenia and BrS share similar calcium channel abnormalities, which may result in aberrant myocardial conductivity. It remains uncertain if there is a genetic pre-disposition for BrS in a subset of patients with schizophrenia. However, the unmasking of Brugada ECG patterns with the use of certain antipsychotics and antidepressants increases the risk of precipitating SCD, independent of QT prolongation. CONCLUSIONS AND FUTURE DIRECTIONS: Specific cardiology assessment and interventions may be required for the congenital or unmasked Brugada ECG pattern in schizophrenia. The current long-term standard of care for BrS is an implantable cardioverter defibrillator (ICD), but post-implantation psychological effects must be considered. Careful use of antipsychotic and other psychotropic medications is necessary to minimize proarrhythmic effects due to impact on cardiac sodium and calcium ion channels. When prescribing such drugs to patients with schizophrenia, clinicians should be mindful of the potentially fatal unmasking of Brugada ECG patterns and how to manage it. We present recommendations for psychiatrists managing this patient population.

COVID-19 reveals Brugada pattern in an adolescent patient.

A diagnosis of Brugada pattern in paediatric or adolescent patients is rare. COVID-19 is characterised by fevers and a pro-inflammatory state, which may serve as inciting factors for Brugada pattern. Recently described in two adult patients, we report the first case of Brugada pattern in an adolescent with COVID-19.

Pathophysiology of Hyperkalemia Presenting as Brugada Pattern on Electrocardiogram (ECG).

BACKGROUND Brugada phenocopies (BrP) are clinical and electrocardiographic (ECG) entities elicited by reversible medical conditions speculated to have pathogenesis rooted in ion current imbalances or conduction delays within the myocardial wall. During an inciting pathologic condition, it produces ECG patterns identical to those of congenitally-acquired Brugada syndrome and subsequently returns to normal ECG patterns upon resolution of the medical condition. This case report describes a 26-year-old man presenting to the Emergency Department (ED) for suspected heroin overdose with a rare ECG consistent with BrP secondary to acute hyperkalemia. CASE REPORT A 26-year-old man with a history of substance abuse and a seizure disorder presented to the ED for acute encephalopathy secondary to a heroin overdose complicated by severe rhabdomyolysis and acute renal failure. Laboratory investigations showed acute hyperkalemia (potassium of 7.2 mmol/L) in addition to an elevated creatine kinase, severe transaminitis, and elevated creatinine. His ECG on admission revealed Brugada-like changes in leads V1-V2, with subsequent resolution upon bicarbonate administration and normalization of potassium. After initial stabilization, the patient was admitted to the Intensive Care Unit (ICU). His rhabdomyolysis and acute kidney injury improved after copious rehydration. He was found to have community-acquired pneumonia, with a negative infectious disease workup, that improved with antibiotics. Upon resolution of his hypoxemic respiratory failure and improvement in mentation, he was discharged from the hospital. CONCLUSIONS Our case report adds to the growing literature on BrP and highlights the importance of recognizing its characteristic ECG pattern as a unique presentation of a common electrolyte derangement.

Syncope in a patient with acute pulmonary embolism and Brugada Type-2 ECG pattern: Brugada phenocopy or Brugada syndrome?

Brugada phenocopies are clinical entities characterized by electrocardiographic patterns that are identical to true Brugada syndrome, but are elicited by a number of clinical circumstances. ECG normalizes upon resolution of underlying condition, family history of arrhythmic syncope or ventricular arrhythmias is strictly absent and provocative tests with sodium channel blockers have to be negative. We describe herein the case of type-2 ECG Brugada pattern in a patient with acute pulmonary embolism presenting with recurrent syncope but negative provocative test with sodium channel blockers. Transthoracic echocardiography and transcranial Doppler did not show atrial septal defect. In conclusion, to the best of our knowledge no other cases excluded atrial septal defect and paradoxical embolism as a possible cause of acute pulmonary embolism related Type-2 Brugada ECG pattern. Therefore in our case right ventricle transmural myocardial ischemia due to acute pulmonary embolism, mainly secondary to right ventricle stretch, could explain Brugada ECG pattern.

Experimental Models of Brugada syndrome.

Brugada syndrome is an inherited, rare cardiac arrhythmogenic disease, associated with sudden cardiac death. It accounts for up to 20% of sudden deaths in patients without structural cardiac abnormalities. The majority of mutations involve the cardiac sodium channel gene SCN5A and give rise to classical abnormal electrocardiogram with ST segment elevation in the right precordial leads V1 to V3 and a predisposition to ventricular fibrillation. The pathophysiological mechanisms of Brugada syndrome have been investigated using model systems including transgenic mice, canine heart preparations, and expression systems to study different SCN5A mutations. These models have a number of limitations. The recent development of pluripotent stem cell technology creates an opportunity to study cardiomyocytes derived from patients and healthy individuals. To date, only a few studies have been done using Brugada syndrome patient-specific iPS-CM, which have provided novel insights into the mechanisms and pathophysiology of Brugada syndrome. This review provides an evaluation of the strengths and limitations of each of these model systems and summarizes the key mechanisms that have been identified to date.

Link between Brugada phenocopy and myocardial ischemia: Results from the International Registry on Brugada Phenocopy.

BACKGROUND: Brugada phenocopies clinical entities that have indistinguishable electrocardiographic (ECG) patterns from true congenital Brugada syndrome. However, they are induced by other clinical circumstances such as myocardial ischemia. The purpose of our study was to examine the clinical features and pathogenesis of ischemia-induced Brugada phenocopy (BrP). METHODS: Data from 17 cases of ischemia-induced BrP were collected from the International Registry (www.brugadaphenocopy.com). Data were extracted from these publications and authors were contacted to provide further insight into each case. RESULTS: Of the patients included in this study, 71% were male. Mean age was 59 ± 11 years (range: 38-76). Type-1 Brugada ECG pattern occurred in 15/17 (88%) of the cases, while a type-2 Brugada ECG pattern was observed in the other 2/17 (12%). In all cases, the Brugada ECG pattern resolved upon correction of the ischemia, indicating ischemia as the inducing circumstance. No arrhythmic events have been detected acutely or during the follow-up. Reported time to resolution ranged from 2 minutes to 5 hours. Provocative challenges using sodium channel blocking agents were performed in 7/17 cases (41%), and all failed to induce a Brugada ECG pattern (BrP Class A). The remaining 10/17 cases (59%) did not undergo provocative testing due to various clinical reasons. CONCLUSIONS: Myocardial ischemia is a commonly reported etiology of BrP. Importantly, this study found no association between BrP induced by myocardial ischemia and sudden cardiac death or malignant ventricular arrhythmias.