Brugada Syndrome: Case Report and Review of the Literature

In 1992, Brugada and colleagues described a clinical syndrome characterized by a right bundle branch block pattern and ST segment elevations in leads V1-V3, now called Brugada syndrome.¹ Brugada syndrome is associated with sudden cardiac death or idiopathic ventricular fibrillation in structurally normal hearts.

Case Report

A 65-year-old man with a past medical history of hypertension on lisinopril, gastro-esophageal reflux disease and no prior history of coronary artery disease was in his usual state of health when he suddenly collapsed while watching television with his family. His son promptly performed cardiopulmonary resuscitation and emergency medical services were called. He was brought to the emergency room in normal sinus rhythm and was witnessed to spontaneously go into ventricular fibrillation successfully converted by external defibrillation (Figure 1). A 12-lead electrocardiogram (ECG) showed characteristic right bundle branch block and ST segment elevations in leads V1-V3 (Figure 2). He was treated initially with intravenous amiodarone which was subsequently converted to the oral preparation. The patient ruled out for myocardial infarction and was transferred to our hospital for further work-up. A cardiac catheterization revealed no significant coronary artery disease and normal left ventricular function. An electrophysiological study demonstrated easily inducible ventricular fibrillation. An implantable cardioverter-defibrillator (ICD) was implanted and the patient was subsequently discharged.

Discussion

The incidence of Brugada syndrome is estimated at 0.05 to 0.6 percent in adults and 0.0006 percent in children, suggesting that the syndrome manifests primarily during adulthood.^2-4 The mean age of presentation of the victims is 35-40 years; however, patients between two months up to 65 years old have presented with the disease. Patients with Brugada syndrome have an estimated 30 percent chance of sudden cardiac death at three years.⁵ Brugada syndrome can be easily diagnosed by electrocardiography. The ST segment elevations in V1-V3 with the characteristic right bundle branch block pattern are seen. The morphology of the ST segment and right bundle branch patterns are different based on the genetic morphology. Brugada syndrome is consistent with an autosomal dominant inheritance with variable expression. Mutations in the sodium channel gene SCN5A located on chromosome 3p21-23 have been found in several families with the syndrome.⁶ Recently, another mutation was identified on chromosome 3p22-25. However, this gene mutation represents only a minority of patients diagnosed with the syndrome. Other mutations in the SCN5A gene have been associated with other forms of sudden cardiac death, such as long QT syndrome. The mutation associated with Brugada syndrome is associated with a loss of sodium channel function, whereas mutations with long QT syndrome are associated with an excess of sodium inward current.⁵ Clinical presentations of the Brugada syndrome are related to life-threatening ventricular arrhythmias. Males outnumber females with the syndrome.⁸ Sudden cardiac death or syncope is often the first clinical event. The syndrome should be suspected in patients with either documented idiopathic ventricular fibrillation, self-terminating polymorphic ventricular tachycardia, a family history of sudden cardiac death in patients less than 45 years of age and/or syncope with the characteristic electrocardiographic changes. The appearance of the electrocardiographic changes alone represents an idiopathic Brugada ECG pattern and not the Brugada syndrome. The Brugada mutation predisposes individuals to a lifetime risk of sudden cardiac death. There is no effective pharmacologic treatment that has been demonstrated to reduce the risk of sudden death. Both amiodarone and beta blockers are inferior to ICD in this cohort.⁹ The low incidence of events in patients with Brugada syndrome suggests that the majority are likely to remain asymptomatic and have a relatively low risk of recurrent events, unlike the case described herein. Genetic counseling is needed for patients with Brugada syndrome. First-degree relatives with the genetic mutation who are asymptomatic but carry the Brugada type electrocardiogram are still at risk for developing sudden cardiac death. These patients are at risk of transferring the mutation to their offspring. Risk stratification has been proposed by Priori and coworkers into three groups. Patients with baseline ST segment elevation and a history of syncope or idiopathic ventricular fibrillation are at a high risk of developing sudden cardiac death. These patients should undergo implantation of an ICD. Patients with spontaneous ST segment elevation or Brugada pattern ECGs without a prior history of syncope are considered intermediate risk. The treatments for these patients are currently under debate. Patients who are carriers of the genetic mutation or who develop the Brugada-type ECG changes under provocation with intravenous ajmaline, flecanide or procainamide are at low risk for developing sudden cardiac death. These patients may be reassured and advised to follow up in any event of palpitations or syncope.^10,11 Brugada syndrome can cause sudden cardiac death in structurally normal hearts. This rare genetically predisposed disease should be considered in all patients with the presentation of ST segment elevations in V1-V3 along with a right bundle branch block with symptoms suggestive of ventricular tachyarrhythmias.