Types of accessory pathways

Diagram of 4 types of abnormal conduction pathways: classic accessory atrioventricular pathway (red), atriofascicular pathway (green), fasciculoventricular pathway (light blue), and nodoventricular pathway (dark blue). The atrioventricular node and His-Purkinje system are represented in yellow. Atrioventricular, atriofascicular, and nodoventricular pathways are capable of supporting atrioventricular reciprocating tachycardias. In contrast, an isolated fasciculoventricular pathway can cause subtle preexcitation but does not support clinical tachycardia.