Arrhythmias induced by dextrose-insulin challenge test in nondiagnostic Brugada ECG patterns

Area of Science:

• Cardiology
• Electrophysiology

Background:

• Brugada syndrome (BrS) is characterized by dynamic electrocardiogram (ECG) changes that are not always apparent.
• Several factors can influence ECG patterns in BrS, necessitating specific diagnostic challenges.

Purpose of the Study:

• To evaluate the efficacy of a dextrose-insulin challenge test in unmasking diagnostic ECG abnormalities in patients with suspected Brugada syndrome and nondiagnostic baseline ECGs.

Main Methods:

• Six patients with nondiagnostic Brugada ECG index patterns underwent a dextrose-insulin challenge test.
• ECG monitoring was performed to assess for J-ST segment elevation and arrhythmias during the challenge.

Main Results:

• Four out of six patients exhibited J-ST segment elevation following the dextrose-insulin challenge.
• The challenge test also successfully triggered arrhythmias in these patients, confirming the diagnosis.

Conclusions:

• The dextrose-insulin challenge test is effective in unmasking Brugada syndrome in patients with initially nondiagnostic ECGs.
• The test's ability to induce characteristic ECG changes and arrhythmias supports its utility in diagnosing BrS.
• The underlying mechanism may involve insulin-induced alterations in ion currents, specifically K+ efflux, leading to repolarization dispersion and arrhythmogenicity specific to BrS.