Accessory pathway

In cardiology, an accessory pathway is an additional electrical connection between two parts of the heart.^[1] These pathways can lead to abnormal heart rhythms (arrhythmias) associated with symptoms of palpitations. Some pathways may activate a region of ventricular muscle earlier than would normally occur, referred to as pre-excitation, and this may be seen on an electrocardiogram. The combination of an accessory pathway that causes pre-excitation with arrhythmias is known as Wolff–Parkinson–White syndrome.^[2]

Accessory pathways are often diagnosed using an electrocardiogram, but characterisation and location of the pathway may require an electrophysiological study. Accessory pathways may not require any treatment, but those causing symptoms may be treated with medication including calcium channel antagonists, beta blockers or flecainide.^[3] Alternatively, the electrical conduction through an accessory pathways can be abolished using catheter ablation, potentially offering a permanent cure.^[3]