**Question:** Wolff - Parkinson - White (WPW) syndrome is characterised by

A. Premature atrial contractions
B. Bundle branch blocks
C. Ventricular arrhythmias
D. Atrioventricular reentrant tachycardia

**Correct Answer:** D. Atrioventricular reentrant tachycardia

**Core Concept:** Wolff-Parkinson-White (WPW) syndrome is a pre-excitation syndrome characterized by an accessory pathway between the atria and ventricles, which allows electrical impulses to bypass the normal heart conduction system. This results in the development of atrioventricular reentrant tachycardia, also known as WPW tachycardia.

**Why the Correct Answer is Right:** Atrioventricular reentrant tachycardia is the correct answer because it is the primary arrhythmia associated with Wolff-Parkinson-White syndrome. In this condition, an accessory pathway allows electrical impulses to travel between the atria and ventricles, bypassing the normal atrioventricular node. This results in the formation of a reentrant circuit, enabling rapid electrical impulses to travel counterclockwise around the accessory pathway, leading to the development of WPW tachycardia.

**Why Each Wrong Option is Incorrect:**

A. Premature atrial contractions (PACs) are common in WPW syndrome, but they are not the defining characteristic of the syndrome itself. WPW syndrome is characterized by the presence of an accessory pathway, which leads to the development of WPW tachycardia.

B. Bundle branch blocks are abnormalities in the heart's electrical conduction system, which is unrelated to the features of WPW syndrome. In contrast, WPW syndrome is characterized by an accessory pathway causing pre-excitation and arrhythmias like WPW tachycardia.

C. Ventricular arrhythmias are not specific to WPW syndrome. WPW syndrome is characterized by pre-excitation due to an accessory pathway, leading to WPW tachycardia. Ventricular arrhythmias may occur in WPW syndrome, but they are not the primary defining feature.

D. Atrioventricular reentrant tachycardia (D) is a misnomer and should be referred to as WPW tachycardia (D). This is the correct term for the tachycardia associated with WPW syndrome, which is characterized by pre-excitation due to an accessory pathway and the subsequent formation of a reentrant circuit involving the accessory pathway, leading to the rapid conduction of electrical impulses and the development of WPW tachycardia.

**Clinical Pearl:** Wolff-Parkinson-White syndrome is a pre-excitation syndrome caused by an accessory pathway, resulting in the formation of a reentrant circuit and the development of WPW tachycardia. This condition should be recognized and managed appropriately to prevent complications and ensure optimal patient care.