JOURNAL OF THE LOUISIANA STATE MEDICAL SOCIETY
The patient had Enterococcus faecalis bacteremia from a genitourinary source. Hewas treatedwithappropriateantibiotics and had urologic intervention with left ureteral stenting. His hospital course was uneventful, and he was discharged with no cardiac sequelae. He had an outpatient biopsy of the retroperitoneal fibrosis indicating an idiopathic etiology. An EKG wasrepeatedonemonthlaterafterresolutionofhissepsis(Figure2).
of the sodium channel can be temperature-sensitive. 8 Fever might also impair conductance of the sodium channel.⁹
Diagnosis
Expert Consensus statement for type 1 and type 2 Brugada are defined 3 :
1. Brugada syndrome is diagnosed inpatientswith ST-segment elevation with type I morphology ≥2 mm in ≥ 1 lead among the right precordial leads V1,V2 positioned in the 2nd, 3rd, or 4th intercostal space occurring either spontaneously or after provocative drug test with intravenous administration of Class I antiarrhythmic drugs 2. Brugada syndrome is diagnosed in patients with Type 2 or Type 3 ST-segment elevation in ≥1 lead among the right precordial leads V1,V2 positioned in the 2nd, 3rd, or 4th intercostal space when a provocative drug test with intravenous administration of Class I antiarrhythmic drugs induces a Type 1 EKG morphology.
DISCUSSION
Definition
The Brugada syndrome is an autosomal dominant genetic disorder with incomplete penetrance or polygenic inheritance affecting the sodium channels. Brugada syndrome is characterized by abnormal surface EKG findings in conjunction with an increased risk of ventricular tachyarrhythmias and sudden cardiac death. EKG findings typically consist of persistent ST segment elevation in leads V1 to V3 and the presence of a pseudo-right bundle branch block. These EKG changes are dynamic, often hidden, and may reveal themselves in the presence of triggers like fever, intoxication (alcohol, cocaine, or cannabis), vagal stimulation, electrolyte imbalance, anesthetics (propofol, bupivacaine), psychotropic agents (amitriptyline, lithium), and sodiumchannel blockers. 1 Patients with typical EKG featureswho are asymptomatic andhave noother clinical criteria are said to have Brugada pattern such as the patient in this case.
Prognosis and Risk Stratification
The relation between the Brugada EKG sign in asymptomatic patients (no history of syncope, ventricular arrhythmias or SCD (sudden cardiac death)) and the future risk of developing arrhythmogenic events has been investigated. One study revealed that the cardiac event rate per year in asymptomatic patients was 0.5%, compared to 1.9% in patients with a history of syncope and 7.7% in patients with aborted SCD. 13 Multiple predictors of future arrhythmic events in patients with the Brugada pattern were studied, with male gender, mutation of the SCN5A gene and a positive family history of SCD found to be non -predictive. 13,14,15 The prognostic value of the clinical, EKG and Electrophysiology Studies (EPS) variables were analyzed in a population of spontaneous type 1 Brugada ECG patterns and no previous cardiac arrest. The cohort with negative EPS (non- inducibility of VT/VF) had a 1.8% risk of developing arrhythmic events (SCD or documented VF), compared to 14% in those with a positive EPS. 15 Further studies revealed a 0.9% rate of significant cardiac events in patients with non-inducible arrhythmias. 14,15 A positive EPS is not predictive for arrhythmic events, and data reported that the spontaneous ECG pattern and the history of syncope are the best available predictors of such events. 13,16
Prevalence
The prevalence of Brugada syndrome appears to be low in the general population. A family history is present in about 20- 30% of patients. 10 According to recent studies in Europe, the incidence of sudden death in the general population (age 7-64 years) is 1.34 per 100,000 per year. 4 Studies in heterogeneous populations suggest that the majority of patients were of Asian decent. 5 However, one article looking at Brugada pattern on EKG stated none of the patients with fever-induced Brugada were of southeast Asian origin or had electrolyte imbalance, significant bradycardia, and prolonged PR interval when their type I pattern was recognized. In addition, none of the eight patients with fever-induced type I Brugada had a history suggestive of arrhythmic symptoms. 6 The prevalence of type I Brugada pattern is 20 times higher among patients presenting with fever than in afebrile patients (2% vs 0.1%). 6
Therapies
Pathophysiology
An Implantable Cardioverter (ICD) Device is the only proven effective therapeutic strategy for the prevention of SCD in Brugada syndrome. It is important to note that ICD’s do have disadvantages, especially young active individuals, who will require multiple device replacements during their life-time. Asymptomatic Brugada syndrome patients do not qualify for an ICD as their risk for life threatening events is very low. 17 calcium current), has proved to be useful for treatment of electrical storm in Brugada syndrome but controlled data on its therapeutic role are not available. 18 Isoproterenol (which increases the L-type
Genetic analysis in patients with Brugada syndrome has shown an association with sodium channel SCN5A mutations in about 20% of the cases. 2 This patient had Brugada Type 1 EKG pattern induced by fever. The predominance of outward ionic current (Ito) at the end of phase 1 of the action potential either because of an increase of its magnitude or because of a decrease in inward currents (INa, ICaL) causes loss of the action potential dome with marked shortening of the action potential. The greater density of the Ito current in the epicardium causes a transmural dispersion of repolarization that manifest as a J wave or ST-segment elevation. 7 Accelerated inactivation
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