Symptoms, particularly syncope and sudden death, usually appear between the ages of 40 and 50. These symptoms occur with no warning. In one study of 163 patients in which ventricular fibrillation occurred in 22% percent, the following observations were made: 12:1 male to female ratio, 58% of Asian origin, and mean age at first abnormal heart rhythm detected was 22–65, but occurred more often in the 40–50 age group. Most of these patients had a family history of syncope, sudden death, or abnormal ECG changes.
In Brugada syndrome sudden cardiac death is often preceded by several episodes of syncope. Brugada syn¬drome is believed to cause approximately 30% of all cases of ventricular fibrillation of unknown cause. Remme et al. reported that the vast majority of patients showed no evidence of structural heart disease but the electrical sys¬tem has a minor derangement, probably in the bundle of His–Purkinje electrical conducting system that in some individuals can trigger ventricular fibrillation and death.
In these patients the ECG is diagnostic and shows a distinctive type of right bundle branch block. The ST segment is elevated in chest leads V1, V2, and V3 where the right bundle branch pattern is usually seen. Figures 1–5 show the ECG tracing in a patient with Brugada syn¬drome. The elevated ST segment has a curious convex curve or a coved and saddle back shape. The ECG is abnormal but the heart is structurally normal. Antiar-rhythmic agents are not effective in preventing ventricular fibrillation in these patients and implantation of a cardio-verter defibrillator is advisable to prevent sudden death.