What question did this study set out to answer?

To evaluate the effectiveness of low dose oral flecainide for unmasking electrocardiographic patterns associated with Brugada syndrome.

December 1, 2022European Heart Journal - Case ReportsOpen Access

Provocative testing using low dose oral flecainide for diagnosis of Brugada syndrome: a report of two cases

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Why the study?

Studies have evaluated oral Flecainide 400 mg for provocative testing in Brugada syndrome, but the clinical utility of lower dose Flecainide (300 mg) had never been documented.

Does low dose oral flecainide (300 mg) unmask the Brugada electrocardiographic pattern in patients suspected of Brugada syndrome?

Key Points

To evaluate the effectiveness of low dose oral flecainide for unmasking electrocardiographic patterns associated with Brugada syndrome.
Administered 300 mg oral flecainide to two patients with suspected Brugada syndrome.
Monitored electrocardiographic changes over a period of 4.5 hours post-administration.
Assessed for any adverse cardiac events during the testing.
Type 1 electrocardiographic pattern developed 30 minutes after drug administration.
Maximal ST-elevation was observed between 3.5 to 4.5 hours following administration.
No incidents of atrioventricular block or ventricular arrhythmia were recorded during the procedures.

Structured PICO

Does low dose oral flecainide (300 mg) unmask the Brugada electrocardiographic pattern in patients suspected of Brugada syndrome?

Population

2 patients suspected of Brugada syndrome

Intervention

Low dose oral flecainide (300 mg)

Outcome

Unmasking of Brugada electrocardiographic pattern (type 1 ECG)surrogate

Low dose oral flecainide (300 mg) may be an effective and safe alternative for provocative testing to unmask Brugada syndrome.

Implication

Hypothesis-generating for low-dose flecainide in Brugada diagnosis; prospective trials needed before clinical adoption.

Abstract

Background: Brugada syndrome (BrS) is a genetic disease characterized by coved ST-segment elevation in the right precordial leads that predispose to life-threatening ventricular tachyarrhythmia. The electrocardiographic signature is dynamic and often concealed but can be unmasked by potent sodium channel blockers such as Flecainide. Some studies have evaluated the effectivity of oral Flecainide 400 mg for provocative testing, but clinical utility of lower dose Flecainide (300 mg) has never been documented. Case summary: These two cases illustrate the effectiveness of low dose oral Flecainide to unmask Brugada electrocardiographic pattern. In our patients, diagnostic type 1 electrocardiography started to develop 30 min after drug administration and reached maximal positivity at 3.5-4.5 h. No atrioventricular block or ventricular arrhythmia was observed during the procedures. Discussion: A potent sodium channel blocker facilitates marked reduction of the right ventricle epicardial action potential, which creates a transmural voltage dispersion and manifests as an ST elevation in the right precordial leads. Time to positivity was comparably rapid, and time to maximal ST-elevation appeared close to peak plasma level of Flecainide (ranging from 1 to 6 h). Although asymptomatic patients have a low rate of adverse cardiac events, it is crucial to inform patients to avoid various modulators and precipitating factors that could trigger malignant arrhythmias.