Supraventricular tachycardia with RBBB pattern
(Click on the image for an enlarged view)
Supraventricular tachycardia with RBBB pattern as evidenced by the slurred S wave in lead I and aVL and rSR’ pattern in V1. The right bundle conduction is slower during tachycardia and hence right bundle aberrancy is more likely to occur than left bundle aberrancy. It could also be a pre-existing right bundle branch block. In this case the person had Ebstein’s anomaly of tricuspid valve. Ebstein’s anomaly can be associated with RBBB pattern or polyphasic QRS complexes. They can also have right sided accessory pathways which can predispose to atrioventricular re-entrant tachycardia.