Wolff- Parkinson - White syndrome

Question 1

Define WPW syndrome

Answer 1

It is a congenital abnormality which can result in supraventricular tachycardias…

that use an accessory pathway. It is a pre-excitation syndrome.

Question 2

Explain the aetiology/risk factors of WPW syndrome

Answer 2

• The accessory pathway (Bundle of Kent) is likely to be congenital

• Associations:
○ Congenital cardiac defects
○ Ebstein’s anomaly (congenital malformation of the heart characterised by
displacement of septal and posterior tricuspid leaflets)
○ Mitral valve prolapse
○ Cardiomyopathies (e.g. HOCM)

Question 3

Summarise the epidemiology of WPW syndrome

Answer 3

• Relatively COMMON
• Most common of the ventricular pre-excitation syndromes
• Found in ALL AGES
• More common in the YOUNG
• Prevalence decreases with age

Question 4

Recognise the presenting symptoms and signs of WPW syndrome

Answer 4

• SVT may occur in early childhood
• Often ASYMPTOMATIC - may be an incidental finding of an ECG

• Symptoms:
○ Palpitations
○ Light-headedness
○ Syncope
In other words;
Sudden onset of a pounding heartbeat
Pulse that is regular and “too rapid to count”
Typically, a concomitant reduction in their tolerance for activity
Younger children may report chest pain.

• Paroxysmal SVT may be followed by a period of polyuria, due to atrial dilatation
and release of ANP
• Sudden death - if SVT deteriorates into VF
• Clinical features of associated cardiac defects (e.g. mitral valve prolapse,
cardiomyopathy)

Question 5

Identify appropriate investigations for WPW syndrome

Answer 5

• ECG may be normal if the conduction speed of the impulse along the accessory pathway matches the conduction speed down the bundle of His
• Classic ECG findings:
• Short PR interval
• Broad QRS complex
• Slurred upstroke producing a delta wave
• Patient may be in SVT (AVRT)
• Bloods - mainly to rule out other causes of arrhythmia (i.e. electrolyte imbalances etc)

• Echocardiogram;

• Abnormal interventricular septal motion (present in some cases)
• Use to exclude other congenital heart defects and cardiomyopathy.