Accessory pathways are usually located where?

• A. AV annulus
• B. Interventricular septum
• C. Pulmonary veins
• D. Sinus node region

Answer: (A)

Accessory pathways are abnormal conduction bundles that bypass the AV node, linking atrial to ventricular tissue outside the normal AV nodal route. They most commonly lie along the AV annulus—the fibrous ring surrounding the mitral and tricuspid valve orifices. This annular region provides a ready-made path for impulses to travel from atria to ventricles, which is why these pathways are classically located there and can cause pre-excitation and reentrant tachycardias.

Locations like the interventricular septum, pulmonary veins, or sinus node region aren’t the typical substrate for accessory pathways. The septum can host rare variants, but the classic site remains the AV annulus.