https://orcid.org/0000-0002-2281-174X
A 42-year-old man with no prior medical history was hospitalized for an uncomplicated myocarditis. Two weeks after discharge, he was transferred to our centre in an arrhythmic storm. His electrocardiogram showed a broad complex tachycardia with a left bundle branch block (LBBB) pattern very similar to that in sinus rhythm, suggestive of a bundle branch re-entrant ventricular tachycardia (BBR-VT) (Panel A). Cardiac MRI was compatible with active myocarditis with pronounced myocardial oedema. Electrophysiological findings demonstrated the main hallmarks of BBR-VT, a form of ventricular tachycardia that includes both bundles and ventricular septum in its re-entrant circuit. A conduction delay in the His–Purkinje system is necessary to initiate the tachycardia. Interestingly, there was important oedema in the septal region of the left ventricle due to the myocarditis, which could lead to the conduction abnormalities.
An urgent catheter ablation of the right bundle (RBB) was performed during BBR-VT, resulting in termination and non-inducibility of the tachycardia. Remarkably, after the ablation of the RBB, we observed a marked narrowing of the QRS complex (Panel B). This suggests that the block of the LBB was previously caused by concealed retrograde penetration after RBB activation, but relieved after obtaining a block in the right bundle during ablation.
The full-length version of this report can be viewed at: https://www.escardio.org/Education/E-Learning/Clinical-cases/Electrophysiology.
