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Brugada Syndrome in Children
Abstract & Commentary
By John P. DiMarco, MD, PhD, Professor of Medicine, Division of Cardiology, University of Virginia, Charlottesville. Dr. DiMarco is a consultant for Novartis, and does research for Medtronic and Guidant.
Source: Probst V, et al. Circulation. 2007; 115:2042-2048
Synposis: In children affected by Brugada syndrome there is no male predominance, a very strong linkage to febrile episodes and a high incidence of SCN5A mutations.
Probst et al reports on the clinical characteristics of 30 children in whom a diagnosis of the Brugada syndrome was made before age 16. The patients were collected from 13 tertiary hospitals in European countries. The diagnosis of Brugada syndrome was made because of either syncope thought due to arrhythmia (n=10), aborted sudden death (n=1), symptomatic supraventricular arrhythmias (n= 1), an abnormal ECG (n=1) or an ECG obtained during family screening for Brugada syndrome (n=17). All patients showed either a Brugada type 1 ECG spontaneously (n=17) or after drug challenge (n=13). The group included 17 boys and 13 girls. Among the 12 symptomatic patients, there were 8 boys and 4 girls. The age at diagnosis for the entire group was 8.5 years. In 25 patients, one other family member with Brugada syndrome was also identified. Genetic screening for mutations in the SCN5A gene was performed in 21 patients and a mutation was found in 15. Most episodes of syncope took place at rest with only one patient reporting syncope during exercise. Fever, however, was an important precipitant. Episodes of syncope or sudden death were associated with fever in 5 of 11 cases. Four of the patients had supraventricular tachycardia which caused syncope in 3 patients. Sinus node dysfunction was documented in 2 patients. Drug challenge with either intravenous flecainide or ajmaline was performed in 16 of 30 patients and all had a type 1 Brugada syndrome response. No complications from drug challenge were reported. Electrophysiologic study was only performed in 6 patients. Three had inducible ventricular tachycardia or ventricular fibrillation. Treatment was variable. Five patients received an ICD. Two of these patients had appropriate ICD shocks during follow-up and one patient developed an ICD infection necessitating removal of the device. One patient diagnosed at age 1, who was not being treated, had an episode of sudden death. Four patients were treated with quinidine with a mean follow-up of 28 + 24 months. None of these patients developed side effects and none developed symptomatic arrhythmias or syncope while on therapy.
The authors present their findings as the largest series of children affected by Brugada syndrome. In contrast to adult population, there is no male predominance, a very strong linkage to febrile episodes and a high incidence of SCN5A mutations. They argue these observations should influence decision making in caring for family members of adults with Brugada syndrome.
Brugada syndrome was first described about 15 years ago. Over 1500 adults with Brugada syndrome have been reported. Arrhythmias in the Brugada syndrome are thought to be due to reduction in the inward sodium current. In areas where these is a strong outward current, such as the right ventricular epicardium, these leads to a shortened action potential and arrhythmias. Most patients with Brugada syndrome present after puberty with the most common appearance of symptoms between age 30 and 50. In adults there is a strong male predominance. This report documents that Brugada syndrome can occur in children and result in life-threatening symptoms. It appears likely that gender related changes in cardiac ion channels result in the male dominant pattern seen in adults.
Several observations in this series are of clinical value. First, quinidine appears to be a reasonable choice for therapy in children in whom placement of an ICD would be problematic. Second, fever is an important risk factor. Observation with monitoring and vigorous attempts to keep fevers under control should be the rule in children with known Brugada syndrome. Finally, in asymptomatic individuals with a Type I ECG pattern only with provocation, careful observation without therapy seems justified.