Wolff-Parkinson-White Syndrome

Question 1

def

Answer 1

tachyarrhythmias due to an accessory AV pathway
characterised by:
1 PR <120ms
2 QRS>120ms caused by a delta wave
accessory pathways (APs) that manifest as both pre-excitation and cause tachycardia

Question 2

what does a delta wave represent

Answer 2

antegrade conduction through an accessory pathway

Question 3

simple def of WPW syndrome

Answer 3

a pre-excitation syndrome

abnormal accessory electrical conduction between atria and ventricles

Question 4

what is it called when an AP conducts anterogradely (atria to ventricles)

Answer 4

manifest as pre-excitation
1 short PR
2 long QRS by delta wave

Question 5

aetiology

Answer 5

an extra electrical pathway (accessory pathway) which causes a rapid heartbeat is present at birth

• abnormal gene
• ebsteins anomaly

in normal hearts electrical impulses travel from SA node across the atria, causing contraction of the atria, to the AV node, which slows the electrical signal to allow the ventricles to fill, before sending the impulse to the ventricles, which causes contraction of the ventricles

in WPW syndrome, an extra electrical pathway connects the atria and ventricles and bypasses the AV node, therefore the ventricles are activated and contract too early

Question 6

epi

Answer 6

affects all ages
most often present in teens/20s
males>females

Question 7

history

Answer 7

1 dizziness/syncope
2 palpitations
3 SOB

in more serious WPW syndrome (with AF)
1 chest pain/tightness

Question 8

examination

Answer 8

1 tachycardia

2 normal BP/hypotension

Question 9

investigations

Answer 9

1 ECG
-tachycardia
-PR<120ms
-wide QRS>120ms
-delta wave
2 24 Holter
3 bloods
-to exclude non-cardiac causes of tachycardia

Question 10

what two major types of rhythm disturbances can WPW syndrome cause

Answer 10

1 looped electrical impulses
-electrical impulses travel down either the normal or extra accessory pathway and up the other
-this condition (AV reentrant tachycardia) sends impulses to the ventricles rapidly
-ventricles pump quickly causing tachycardia
2 disorganised electrical impulses
-if impulses dont begin correctly in RA, they travel across the atria in a disorganised fashion
-disorganised signals and extra accessory pathway of WPW cause ventricles to pump rapidly
-ventricles dont fill completely, and dont pump enough blood to rest of body

Question 11

what is contraindicated in WPW

Answer 11

digoxin use