Brugada syndrome is an inherited arrhythmogenic disorder, characterised by coved-type ST-segment elevation in the right precordial leads, and is associated with increased risk of sudden death. It is genetically and clinically heterogeneous, presenting typically in the fourth or fifth decade of life. The prevalence of Brugada syndrome in the paediatric population is low compared with the adult population. Interestingly, over the last several years, there has been growing evidence in the literature of onset of the disease during childhood. Most of the paediatric cases reported in the literature consist of asymptomatic Brugada syndrome; however, some patients manifest the disease at different regions of the cardiac conduction system at a young age. Early expression of the disease can be affected by multiple factors, including genetic substrate, hormonal changes, and still unknown environmental exposures. The initial manifestation of Brugada syndrome in children can include sinus node dysfunction and atrial arrhythmias. Brugada syndrome can also manifest as ventricular arrhythmias leading to sudden death at an early age. In symptomatic children, performance of the ajmaline test by an experienced team can be safely used as a diagnostic tool to unmask latent Brugada syndrome. Defining indications for an implantable cardioverter defibrillator in children with the diagnosis of Brugada syndrome remains challenging. Given the rarity of the syndrome in children, most paediatric cardiologists will only rarely see a young patient with Brugada syndrome and there is still no universal consensus regarding the optimal management approach. Care should be individualised according to the specific clinical presentation, taking into account the family history, genetic data, and the family’s specific preferences.

We have investigated the hearts from 153 infants found dead in their cots at ages ranging from one month to one year. The deaths occurred over a period of five years (January 1986 to December 1990) and were studied in a center for the study of the sudden infant death syndrome located in Paris. The epidemiological characteristics of this group are:male predominance (sex ratio 1.43), age less than four months (82%), and a predominance of winter deaths. These are the characteristic features ofthe sudden infant death syndrome. Ofthe 143 children studied with the permission of their parents, 24 (16.8%–12 girls and 12 boys) had histological lesions consistentwith myocarditis according to the Dallas criteria. The histological diagnosis of myocarditis is based on the association of cellular necrosis with a mononuclear or mixed inflammatory infiltrate. Cytoplasmic vacuolization, the presence of inflammatory cells in myocytes, and rupture of the cell walls of myocardial fibres are the equivalent histological signs of cellular necrosis. Myocarditis was diversely associated with respiratory, hepatic, muscular, gastrointestinal and/or neurological involvement. Twelve infants had previously been ill. Two died during the course of a serious illness. In only four cases was a viral association demonstrated. This incidence of myocardial involvement, similar to thatdescribed elsewhere in the literature, suggests that myocarditis could be a pathogenic explanation of some deaths thought on general autopsy investigation to be sudden and unexplained.

There is a consensus that sudden infant death syndrome, the leading cause of mortality in the first year of life, is multifactorial. Most of the cases are probably due to respiratory or cardiac disorders. It has been proposed that some cases of sudden infant death might result from ventricular fibrillation triggered by a sudden increase in sympathetic activity affecting the heart with reduced electrical stability. This impairment can be due to an insufficient or delayed development of cardiac vagal innervation, with the resultant lack of its protective effect that has been demonstrated to be present since the third week of life. Clinical studies suggest that some of the sudden infant death victims may have a reduced heart rate variability that could be interpreted as a decreased parasympathetic activity to the heart. On the other hand, a reduced cardiac electrical stability may be provoked by a developmental imbalance in sympathetic innervation such to create a dominance of left-sided nerves. We have demonstrated that an imbalance of this type experimentally induced in puppies increases the susceptibility to ventricular fibrillation and prolongs QT interval. In order to demonstrate a significant relationship between prolonged QT interval and sudden infant death, we performed a large prospective study on 18,832 neonates. QT interval corrected for heart rate (QTc) measured from an electrocardiogram on the fourth day of life, was within the normal limits in nine victims from known causes, while it was exceeding the mean by two standard deviations (>433 msec) in six of 12 sudden infant death victims. If these data are confirmed by a larger multicenter study started in Italy, it will be possible to identify some of the sudden infant death victims by the observation of a prolonged QT interval on the electrocardiogram. In this case a preventive strategy based on a time-limited administration of beta adrenergic blocking agents to the infants at risk, might reduce the incidence of sudden infant death.