Effects of Glucose‐Induced Insulin Secretion on ST Segment Elevation in the Brugada Syndrome

Abstract

Introduction: ST segment elevation in patients with Brugada syndrome is known to fluctuate occasionally, influenced by multiple factors. Insulin has been shown to affect QT dispersion in healthy volunteers, as well as result in abnormality of ventricular repolarization in patients with congenital long QT syndrome. Methods and Results: To assess a possible role of insulin in ST segment elevation in patients with Brugada syndrome, an oral glucose tolerance test (OGTT) was administered to 20 patients with Brugada syndrome and 20 normal patients without ST‐T changes as a control group. Plasma glucose and potassium levels, immunoreactive insulin concentration (IRI), and ST segment elevation and ST‐T wave changes on 12‐lead ECG during OGTT were analyzed. Augmentation (>1 mm) of ST elevation or morphologic changes in ST‐T waves were observed frequently in response to increased IRI during OGTT [15/20 cases (75%)] in patients with Brugada syndrome but in none of the patients in the control group [0/20 cases (0%), P < 0.01 ]. The changes returned to baseline 180 minutes after the glucose load in 9 of 15 patients. Patients who showed coved‐type ST elevation before the glucose load exhibited positive ECG changes more frequently than patients with saddleback‐type elevation or transiently normalized ST segment [8/8 cases (100%) vs 7/12 (58%), P < 0.05 ]. There was no significant difference between the two groups in terms of glucose, IRI, and potassium levels during OGTT. Conclusion: The findings suggest that glucose‐induced insulin secretion is one of the contributing factors to fluctuation of ST segment elevation in patients with Brugada syndrome. (J Cardiovasc Electrophysiol, Vol. 14, pp. 243‐249, March 2003)

Brugada Syndrome and Carbohydrate Metabolism

“…Another study by Nishizaki assessed oral glucose tolerance test (OGTT) in Brugada syndrome patients and control healthy subjects. They found Glucose-induced insulin secretion lead to ST-segment elevation and induce ECG morphologic changes only in patients whereas BG, insulin level and K + level were not significantly different between two groups [16]. Ikeda et al [26] demonstrated that the augmentation of STsegment elevation was associated with a stomach rapidly filled with a large meal [26].…”

“…However, the study of Nishizaki and co-workers found serum K + concentrations were unchanged after the glucose load. They still proposed the possibility that increased K + gradient could affect the repolarization process differently among the three regions of the ventricular walls (endocardium, epicardium and myocardium) cannot be excluded and might contribute to the ST-segment abnormalities observed in patients with Brugada syndrome [16].…”

Spontaneous electrocardiogram alterations predict ventricular fibrillation in Brugada syndrome

“…stomach, fever, glucose insulin test, etc. [17][18][19][20]22,26 ) caused ECG alterations in the patients, we emphasize that spontaneous ECG alterations without any stress often occurred in the patients with a high risk of VF. Patients who had long-term ECG alterations also were likely to have spontaneous AP heterogeneity that causes ECG alterations and VF.…”

Alcohol‐induced Ventricular Fibrillation in Brugada Syndrome

“…Hypokalemia and insulin secretion cause ST segment changes in patients with Brugada syndrome. 2,4) Humoral regulation from alcohol intake may be related to the induction of VF in this case. In addition, it was recently reported that alcohol has an inhibitory effect on single cardiac sodium channel gating.…”