WPW

Question 1

def WPW

Answer 1

Short PR interval and Delta wave on ECG predisposing to supraventricular tachycardias (SVT).

Question 2

aetiology wpw

Answer 2

congenital accessory pathway (bundle of Kent) between atria and ventricles bypasses the atrioventricular node causing ventricular pre-excitation.

the accessory pathway allows electrical current from ventricles to resting atrial myocytes = circuit: atria - AVN - vent - accessory path - atria

This direction is called ‘orthodromic’ conduction and results in narrow QRS complexes as ventricular depolarization is triggered via the bundles of His.

RF - Ebstein’s anomaly - most common congenital abnormality in WPW - associated with single/multiple R sided accessory pathways

Question 3

epi wpw

Answer 3

exact prevalence difficult to know because most asymptomatic

The prevalence of WPW-pattern ECG in the general population is 0.1% to 0.3%

male more

Question 4

sx wpw

Answer 4

palpitations

dizziness

SOB

chest pain

Question 5

signs wpw

Answer 5

atrioventricular re-entrant tachycardia - most common arrhythmia

SVT

afib

a flutter

congenital cardiac abnormalities

Question 6

ix wpw

Answer 6

resting ECG - short PR interval, wide QRS (due to slurred upstroke/delta wave) and ST-T changes

Two types: WPW type A (+ve delta wave in V1), WPW type B (-ve delta wave in V1)

delta waves signify presence of an antegradely conducting AP; no delta waves can mean a concealed retrograde-only AP or an AP with intermittent pre-excitation