Abstract
We present a case of orthodromic atrioventricular re-entrant tachycardia exhibiting both right and left bundle branch block pattern wide QRS morphologies caused by bilateral bystander nodoventricular (NV) accessory pathways. These wide QRS morphologies came from pre-excitation accompanied by delta waves. In the context of NV accessory pathways, left-sided manifest NV accessory pathways are rare.