Masquerading bundle branch block obscuring the diagnosis of Brugada syndrome: an electrocardiographic and vectorcardiographic study

Abstract

Key Clinical MessageWe describe the induction of a masquerading bundle branch block in two patients with Brugada syndrome following the administration of Ajmaline. The development of this conduction disturbance prevented the correct electrocardiographic diagnosis. However, the simultaneously obtained vectocardiogram identified both the Brugada pattern and the masquerading bundle branch block.

Ajmaline-induced Brugada Phenocopy, Right Bundle Branch Block, or Both?

“… 15 Furthermore, it should be kept in mind that the administration of sodium channel blockers could not only elicit the coved ST-segment elevation characteristic of type 1 Brugada pattern but also induce an RBBB that can preclude the ECG manifestations of BrS. 16 As placing the right precordial ECG leads at an upper position (second or third intercostal space) increases the sensitivity of ECG to detect all types of BrS, 3 it would be nice to take an ECG at upper intercostal spaces and perform an ajmaline test to unmask the true RBBB effect.…”