Enhancement of J-ST-segment elevation by the glucose and insulin test in Brugada syndrome

The effects of glucose and insulin on J-ST-segment elevation were evaluated in seven men (mean age 45 +/- 10 years) with Brugada syndrome. Six patients had been reanimated from VF and one patient had experienced syncope. The effects of intavenous (1) pilsicainide 50 mg, (2) glucose 50 g, and (3) glucose 50 g plus regular insulin 10 IU on the precordial ECG leads were examined. Pilsicainide significantly enhanced J-ST elevation in all patients and induced VF in 1 patient. A significant accentuation of the abnormal J-ST configuration was observed in all patients at a mean of 51 +/- 40 minutes after glucose and insulin infusion. Changes in blood glucose and serum potassium concentration were 111 +/- 158 mg/dL and -0.30 +/- 0.48 mEq/L, respectively. These changes were not directly related to the ECG changes. Glucose infusion without insulin caused a subtle increase in J-ST elevation. In conclusion, the administration of glucose and insulin safely unmasked or accentuation the J-ST-segment elevation in Brugada syndrome. Blood glucose and insulin concentrations may be factors modulating the circadian or day-to-day ECG variations in this syndrome.