Electrocardiographic pattern of Brugada syndrome disclosed by a febrile illness: clinical and therapeutic implications

Incidence of ventricular arrhythmias related to COVID infection and vaccination in patients with Brugada syndrome: Insights from a large Italian multicenter registry based on continuous rhythm monitoring

INTRODUCTION

Brugada syndrome (BrS) has a dynamic ECG pattern that might be revealed by certain conditions such as fever. We evaluated the incidence and management of ventricular arrhythmias (VAs) related to COVID-19 infection and vaccination among BrS patients carriers of an implantable loop recorder (ILR) or implantable cardioverter-defibrillator (ICD) and followed by remote monitoring.

METHODS

This was a multicenter retrospective study. Patients were carriers of devices with remote monitoring follow-up. We recorded VAs 6 months before COVID-19 infection or vaccination, during infection, at each vaccination, and up to 6-month post-COVID-19 or 1 month after the last vaccination. In ICD carriers, we documented any device intervention.

RESULTS

We included 326 patients, 202 with an ICD and 124 with an ILR. One hundred and nine patients (33.4%) had COVID-19, 55% of whom developed fever. Hospitalization rate due to COVID-19 infection was 2.76%. After infection, we recorded only two ventricular tachycardias (VTs). After the first, second, and third vaccines, the incidence of non-sustained ventricular tachycardia (NSVT) was 1.5%, 2%, and 1%, respectively. The incidence of VT was 1% after the second dose. Six-month post-COVID-19 healing or 1 month after the last vaccine, we documented NSVT in 3.4%, VT in 0.5%, and ventricular fibrillation in 0.5% of patients. Overall, one patient received anti-tachycardia pacing and one a shock. ILR carriers had no VAs. No differences were found in VT before and after infection and before and after each vaccination.

CONCLUSIONS

From this large multicenter study conducted in BrS patients, followed by remote monitoring, the overall incidence of sustained VAs after COVID-19 infection and vaccination is relatively low.

Cardiovascular Complications of Chimeric Antigen Receptor T-Cell Therapy: The Cytokine Release Syndrome and Associated Arrhythmias

In recent years, cancer treatment has evolved, and new therapies have been introduced with significant improvement in prognosis. The immunotherapies stand out owing to their efficacy and remission rate. Chimeric antigen receptor (CAR) T-cell therapy is a part of this new era of therapies. Chimeric antigen receptor T-cell therapy is a form of adoptive cellular therapy that uses a genetically encoded CAR in modified human T cells to target specific tumor antigens in a nonconventional, non-major histocompatibility complex (MHC) protein presentation. Chimeric antigen receptor T-cell therapy successfully identifies tumor antigens and through activation of T cells destroys tumoral cells. It has been found to efficiently induce remission in patients who have been previously treated for B-cell malignancies and have persistent disease. As the use of this novel therapy increases, its potential side effects also have become more evident, including major complications like cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). Cytokine release syndrome is a major systemic inflammatory process as a result of massive cytokine production by the proliferating and activated CAR T cells in which multiple interleukins and immune cells contribute to the inflammatory response. Cytokine release syndrome has been associated with cardiovascular life-threatening complications including hypotension, shock, tachycardia, arrhythmias, left ventricular dysfunction, heart failure, and cardiovascular death. Arrhythmias, among its major complications, vary from asymptomatic prolonged corrected QT interval (QTc) to supraventricular tachycardia, atrial fibrillation, flutter, and ventricular arrhythmias like Torsade de pointes. This article focuses on the cardiovascular complications and arrhythmias associated with CRS and CAR T-cell therapy.

Electrocardiogram Characteristics and Arrhythmic Events during Fever in Patients with Fever-Induced Brugada Syndrome

Introduction: Changes in electrocardiogram (ECG) parameters and the incidence of arrhythmic events in patients with fever-induced Brugada syndrome (BrS) remain unknown. Objective: We aimed to investigate the effect of hyperthermia on the ECG pattern and the occurrence of fever-triggered arrhythmic events (FTAEs) in patients with fever-induced BrS. Methods: We retrospectively analyzed a series of fever-induced BrS cases from January 1966 to November 2018. Clinical characteristics and ECG parameters were evaluated in the presence or absence of fever. Results: Syncope and implantable cardioverter defibrillator implantation occurred more frequently in BrS patients with FTAEs than in patients without FTAEs. In BrS patients <16 years old, more arrhythmia events occurred in patients with FTAEs than in patients without FTAEs (p = 0.04). During follow-up, 2 patients in the FTAEs group suffered new malignant arrhythmic events. Compared to the afebrile state, the J point increased significantly in precordial leads V1, V2, and V3 during the febrile state (all p < 0.01). The corrected QTpeak intervals in V1 and V2 were significantly longer in the FTAEs group than in the non-FTAEs group (354.5 ± 37.0 vs. 334.3 ± 45.5 ms, p < 0.01 and 368.0 ± 43.4 vs. 330.9 ± 41.5 ms, p < 0.01, respectively). An increased corrected QT dispersion and a lengthened corrected Tpeak-Tend dispersion were also observed during fever. Conclusions: Fever may not only reveal BrS but also induce life-threatening arrhythmic events, especially in children and adolescents.

Brugada pattern: a comprehensive review on the demographic and clinical spectrum

A prominent coved or saddle-shaped ST-segment elevation followed by T wave changes in V1-V3 and in the absence of other identifiable cause is termed as Brugada pattern. This pattern in the presence of documented ventricular arrhythmias or its symptoms (syncope, seizure) or significant family for sudden cardiac death or abovementioned ECG changes is called Brugada syndrome. Here we present a comprehensive literature review on the precipitation factors of Brugada syndrome/pattern by various stimuli, its presentation, associations, management and outcomes. We are also presenting a unique case of Brugada pattern where the patient's Brugada pattern was unmasked at an extreme old age by infection.

Syncope in a febrile state: A case report of Brugada syndrome

In 1992, Brugada and Brugada first described a new entity, which became known as Brugada syndrome, that is associated with a high risk of ventricular arrhythmias and sudden cardiac death in patients without structural heart disease. This syndrome is characterized by a distinct electrocardiographic phenotype, type 1 Brugada pattern, consisting of a coved ST-segment elevation (≥0.2 mV) followed by a negative T wave in more than one right precordial lead. This pattern is dynamic, and can be spontaneous or concealed, but is unmasked under certain circumstances, like febrile states. The authors report a case in which the diagnosis of Brugada syndrome was made in the course of etiologic investigation of recurrent syncope in a febrile state.

Concomitant Brugada-like and short QT electrocardiogram linked to SCN5A mutation

Mutations in the α-subunit of cardiac sodium channel gene SCN5A can lead to the overlapping phenotypes of both the Brugada and type 3 long QT syndromes. However, the combination of Brugada and a short QT phenotype resulting from mutation in SCN5A has not previously been described. A man with concomitant Brugada-like and short QT electrocardiogram (ECG) was identified and the SCN5A gene was sequenced. Whole-cell patch clamp analysis of human embryo kidney (HEK) 293 cells expressing a SCN5A channel with the patient's sequence was used to investigate the biophysical properties of the channel. The patient with the family history of sudden death showed Brugada-like and short QT interval ECG. Sequence analysis of the coding region of the SCN5A gene, identified a G to A heterozygous missense mutation at nucleotide site 2066 that resulted in a amino-acid substitution of arginine to histidine at amino-acid site 689 (R689H). Patch clamp analysis showed that the R689H failed to generate current when heterologously expressed in HEK293 cells, indicating it was a loss-of-function mutation. Our finding firstly shows that a heterozygous missense mutation R689H in SCN5A gene results in the loss of protein function and the coexistents of the Brugada-like and short QT interval ECG phenotypes.

Fever-induced ST-segment elevation in a syncopal patient with Brugada syndrome

Brugada syndrome (BS) is associated with life-threatening ventricular tachyarrhythmias. Although a diagnosis of BS can be made by typical electrocardiographic (ECG) findings, these findings for BS vary depending on the patients' physiological conditions and are sometimes normalized or less evident. It is important for emergency physicians to recognize that the typical electrocardiographic findings of BS are not always manifested but sometimes are only unmasked in the presence of a specific condition.

Fever-triggered ventricular arrhythmias in Brugada syndrome and type 2 long-QT syndrome

The risk for lethal ventricular arrhythmias is increased in individuals who carry mutations in genes that encode cardiac ion channels. Loss-of-function mutations in SCN5A, the gene encoding the cardiac sodium channel, are linked to Brugada syndrome (BrS). Arrhythmias in BrS are often preceded by coved-type ST-segment elevation in the right-precordial leads V1 and V2. Loss-of-function mutations in KCNH2, the gene encoding the cardiac ion channel that is responsible for the rapidly activating delayed rectifying potassium current, are linked to long-QT syndrome type 2 (LQT-2). LQT-2 is characterised by delayed cardiac repolarisation and rate-corrected QT interval (QTc) prolongation. Here, we report that the risk for ventricular arrhythmias in BrS and LQT-2 is further increased during fever. Moreover, we demonstrate that fever may aggravate coved-type ST-segment elevation in BrS, and cause QTc lengthening in LQT-2. Finally, we describe molecular mechanisms that may underlie the proarrhythmic effects of fever in BrS and LQT-2. (Neth Heart J 2010;18:165-9.).

A novel SCN5A mutation V1340I in Brugada syndrome augmenting arrhythmias during febrile illness

BACKGROUND

Mutations in the SCN5A gene, which encodes the cardiac sodium channel, have been implicated in the pathogenesis of Brugada syndrome (BrS). Febrile illnesses have been recognized to unmask and/or trigger the BrS phenotype. However, the pathophysiological mechanism has not been fully elucidated.

OBJECTIVE

A novel SCN5A missense mutation, V1340I, was identified in a patient with BrS suffering from frequent episodes of polymorphic ventricular tachycardia (VT) and syncope associated with fever. The biophysical modifications of hNa(v)1.5 by V1340I were studied.

METHODS

The effects of the V1340I mutation were studied in the 2 splice variants, SCN5A and SCN5A-Q1077del (delQ), using patch-clamp techniques at various temperatures between 22 degrees C and 40 degrees C.

RESULTS

At 22 degrees C, V1340I-SCN5A generated markedly diminished sodium currents compared to the wild-type (WT) SCN5A. On the contrary, V1340I-delQ generated almost identical current density compared to the WT-delQ. However, V1340I-delQ significantly attenuated the peak current density compared to the WT-delQ at 32 degrees C, 37 degrees C and 40 degrees C. The voltage dependency of steady-state activation was leftward shifted both in WT-delQ and V1340I-delQ at 40 degrees C. In addition, the V1340I-delQ accelerated the recovery time course from fast inactivation compared to the WT-delQ at 40 degrees C. Immunohistochemical staining showed that both V1340I-SCN5A and V1340I-dQ were expressed in the plasma membrane.

CONCLUSION

Our study supports the concept that febrile illness predisposes individuals who carry a loss of function SCN5A mutation, such as V1340I, to fever-induced ventricular arrhythmias in BrS by significantly reducing the sodium currents in the hyperthermic state.

Brugada syndrome with complete right bundle branch block disclosed by a febrile illness

The characteristic of right-bundle branch block (RBBB) pattern in Brugada syndrome (BS) is an atypical pattern without a wide S wave in left leads. We present a case of a patient with BS who had a typical ECG pattern of complete RBBB (CRBBB) with a wide S wave in the left leads which was disclosed by a febrile illness. Our observations suggest that physicians should be careful to evaluate ECG change in response to a febrile state, even if the ECG shows a typical CRBBB pattern with deep and wide S waves in the left leads.

Brugada syndrome

First introduced as a new clinical entity in 1992, the Brugada syndrome is associated with a relatively high risk of sudden death in young adults, and occasionally in children and infants. Recent years have witnessed a striking proliferation of papers dealing with the clinical and basic aspects of the disease. Characterized by a coved-type ST-segment elevation in the right precordial leads of the electrocardiogram (ECG), the Brugada syndrome has a genetic basis that thus far has been linked only to mutations in SCN5A, the gene that encodes the alpha-subunit of the sodium channel. The Brugada ECG is often concealed, but can be unmasked or modulated by a number of drugs and pathophysiological states including sodium channel blockers, a febrile state, vagotonic agents, tricyclic antidepressants, as well as cocaine and propranolol intoxication. Average age at the time of initial diagnosis or sudden death is 40 +/- 22, with the youngest patient diagnosed at 2 days of age and the oldest at 84 years. This review provides an overview of the clinical, genetic, molecular, and cellular aspects of the Brugada syndrome, incorporating the results of two recent consensus conferences. Controversies with regard to risk stratification and newly proposed pharmacologic strategies are discussed.

Temperature modulation of ventricular arrhythmogenicity in a canine tissue model of Brugada syndrome

BACKGROUND

Fever promotes ventricular arrhythmias in Brugada syndrome (BrS). Hypothermia can induce BrS electrocardiogram (ECG) and arrhythmia. However, the mechanisms are unclear.

OBJECTIVE

We evaluated the hypothesis that pathological temperatures promoted arrhythmogenesis by modulating the spatial heterogeneity and functional dynamics of right ventricular electrophysiological activity.

METHODS

We mapped action potentials (APs) on the epicardial or cut-exposed transmural surfaces and recorded transmural ECGs in 27 arterially perfused canine right ventricular preparations before and after inducing BrS at 32 degrees C, 36.5 degrees C, and 40 degrees C.

RESULTS

We observed major intraepicardial dispersion of AP duration (APD) and reversal of transmural gradient of APD in association with manifestation of BrS at 36.5 degrees C. Reducing the temperature to 32 degrees C prolonged APDs and enhanced the phase 1 notch of epicardial APs, while 40 degrees C caused opposite changes. Prominent phase 2 domes of APs frequently led to spontaneous premature ventricular activations (PVAs), which conducted to surrounding regions having shorter APDs. Longer APDs at 32 degrees C and 36.5 degrees C frequently blocked reentry, although they promoted PVA, while shortened APDs at 40 degrees C facilitated reentrant ventricular tachycardia. During bradycardia (2,000 ms), the J-ST elevation in the ECG was enhanced at 32 degrees C and attenuated at 40 degrees C. Rapid pacing (500 ms) eliminated the dome of epicardial APs and enhanced J-ST elevation at each temperature. Blocking the transient outward current, I(to), with 4-aminopyridine reduced J-ST elevation and eliminated the PVA and reentry.

CONCLUSIONS

In this BrS model, prolongation and increased dispersion of APDs promoted spontaneous activation during hypothermia, while APD abbreviation facilitated reentry during hyperthermia. I(to) mediated the arrhythmogenicity.

Failure of cilostazol in the prevention of ventricular fibrillation in a patient with Brugada syndrome

The ECG appearance in Brugada syndrome is caused by failure of the dome of the action potential to develop. Increased activity of the I(to) current in epicardial cells generates a transmural gradient with repolarization dispersion between the epicardium and the endocardium in the right ventricular wall, thus favoring the development of VF by a phase 2 reentry mechanism. The efficacy of cilostazol for the management of these arrhythmias has been reported. This drug is a phosphodiesterase inhibitor with positive chronotropic properties, thus blocking outward potassium currents I(to) in the myocardial tissue. We present a patient with Brugada syndrome with an implantable cardioverter defibrillator (ICD), who suffered multiple ICD discharges due to VF during therapy with this drug.