Sudden death in Brugada syndrome and right ventricular cardiomyopathies. Similarities and differences

In 1992 we described a new syndrome characterized by syncopal or sudden dea th episodes in patients with a structurally normal heart and a characterist ic electrocardiogram 9 showing a pattern of right bundle branch block and S T segment elevation in right precordial leads V1 to V3. The disease is gene tically determined with and autosomic dominant pattern of transmission. Unt il now three mutations and one polymorphism in the sodium cardiac channel g ene have been identified in two families and one sporadic patient. As in ma ny other genetically determined diseases, the disease is heterogeneous, cau sed by more than one gene. The syndrome has been identified in almost all c ountries in the world. Its incidence is difficult to evaluate, but it seems to be responsible for 4 to 10 sudden deaths per year per 10,000 inhabitant s in areas like Laos or Thailand, and it represents the most frequent cause of death in young male adults in these countries. Up to 50% of all sudden deaths in patients with structurally normal heart are caused by the disease . The diagnosis can be easily made thanks to the characteristic electrocard iographic pattern. In some patients, the presence of concealed and intermit tent forms might make the diagnosis more difficult. The electrocardiogram c an be modulated by autonomic changes and administration of antiarrhythmic d rugs. Beta-adrenergic stimulation normalizes the electrocardiogram, whereas ajmaline, flecainide or procainamide administration increase ST segment el evation. These drugs allow the unmasking of concealed or intermittent forms of the disease. Prognosis of patients with the syndrome is poor without an implantable defibrillator and antiarrhythmic drugs like amiodarone or beta blockers do not protect against sudden death. The poor prognosis is similar in patients with a history of aborted sudden death or syncope and in asymp tomatic patients in whom the abnormal electrocardiogram characteristic of t he syndrome, was identified during a routine examination.