Key clinical features a general internist needs to know about Brugada syndrome: a case-based discussion

Abstract

Introduction: Brugada syndrome (BrS) is an autosomal dominant genetic disorder involving the abnormal function of cardiac voltage-gated sodium ion channels. Sodium channel loss of function can lead to early repolarization and loss of the Phase 2 action potential dome in cardiomyocytes. In BrS, this sodium channelopathy occurs in some, but not all, epicardial cells thus creating 1) juxtaposition of depolarized and repolarized cells in the epicardium and 2) a transmural voltage gradient. Together, these conditions can set up a Phase 2 reentry and resultant malignant cardiac arrhythmia. Of the three types of electrocardiogram (EKG) changes seen in BrS, only the Type 1 EKG is considered diagnostic. In a controlled setting, sodium channel blockers and Brugada EKG leads may be used to unmask this diagnostic EKG finding. Fever and certain medications that interfere with the sodium channel can also trigger these changes, which can be catastrophic. Case report: A 26-year-old white male presented with febrile upper respiratory infection symptoms and had an EKG change, which was initially misinterpreted as an ST elevated myocardial infarction due to ST-T segment elevation in leads V1 and V2. The patient reported past recurrent syncopal episodes leading to a recent suspected diagnosis of BrS. A later episode of febrile illness, triggering a Type 1 EKG pattern, led to a subsequent hospital admission for continuous cardiac monitoring. On that occasion, he was placed on a wearable external defibrillator pending placement of implantable cardioverter defibrillator (ICD) device. Conclusion: Due to the gravity of symptoms that can manifest in the BrS patient, it is important to recognize and treat this condition promptly and effectively. BrS patients require admission for continuous cardiac monitoring when febrile and certain medications interfering with the sodium channel should be avoided in this population. Although medications may be used as one treatment modality, definitive therapy is placement of an ICD device.

Keywords

• Brugada syndrome
• sodium channelopathy
• sudden cardiac arrest
• implantable cardioverter defibrillator