Wolff-Parkinson-White syndrome Flashcards
definition
genetic condition where there is an accessory pathway causing abnormal cardiac conduction, a pre-excitation syndrome which can lead to ventricular tachycardia, cardiac arrest and death
who is it more common in?
men
what can it be associated with
congenital structural and other structural cardiac abnormalities - cardiomyopathies and valve defects such as mitral valve prolapse
diagnosis
echo ECG routine bloods/FBC 24 hour holter monitoring stress testing electrophysiology studies
role of echo
check for structural abnormalities
role of FBC
to exclude other causes, will be normal
role of 24 hour holter monitoring
to capture arrhythmias
role of stress testing
to elicit arrhythmias
role of electrophysiology studies
to show accessory pathway for ablation
clinical features
often asymptomatic can present with AF or atrial flutter acute episodes ventricular tachycardia/cardiac arrest acute episodes followed by polyuria
acute episode symptoms
shortness of breath syncope dizziness palpitations chest pain
ECG changes
delta wave short P-R interval non-specific T wave changes AF antidromic conduction orthodermic conduction ST changes pre-excitation
what is a delta wave?
upward slurring of R wave - makes QRS broad
types
A and B
type A ECG changes
positive delta wave and positive QRS in all leads
looks like RBBB
type B ECG changes
negative delta wave and negative QRS in V1 and V2 but positive in other chest leads - looks like LBBB
AF on ECG
> 200bpm
irregular
wide QRS due to bypassing of AVN
antidromic conduction on ECG
200-300bpm
wide QRS due to accessory pathway
orthodermic conduction on ECG
retrograde conduction 200-300bpm no P waves narrow QRS (<120ms) T wave inversion ST depression
ST changes
occur in opposite direction to QRS complex
pre-excitation
occurs during the time outside of acute episodes
how often does atrial flutter occur?
7%
how often does AF occur?
20%
atrial flutter and fibrillation
can lead to ventricular fibrillation or tachycardia due to transfer of rapid atrial rate to ventricles via accessory pathways
atrioventricular re-entry tachycardia
orthodermic conduction
accessory pathway allows electrical signal to return to atria from ventricles - normally prevented by AVN
accessory pathway
bundle of kent
treatment for asymptomatic cases
regular follow ups
radio-frequency ablation therapy
surgical ablation
drug treatment if unwilling/unsuitable for ablation therapy
radio-frequency ablation
destroys accessory pathway
when is surgical ablation done?
if radio-frequency fails or structural abnormalities are present
treatment for atrioventricular re-entry tachycardia
DC cardioversion
amiodarone/flecainide
manage by SVT acute management guidelines
avoid adenosine in AF
treatment for atrioventricular re-entry tachycardia if haemodynamically unstable
synchronised DC cardioversion
treatment for atrioventricular re-entry tachycardia if haemodynamically stable
attempt vagal manoeuvres, adenosine and synchronised DC cardioversion
vagal manoeuvres
blow into syringe and carotid sinus massage
adenosine dosage
6mg
then 12mg if needed
12mg again if unsuccessful
treatment if symptomatic
treat once acute episode is over radiofrequency ablation drug therapy anti-arrhythmic AVN blocker
what is contraindicated?
digoxin
drug therapy for symptomatic disease
amiodarone
flecainide
sotalol
implications if symptomatic
driving/operating heavy duty machinery
prognosis if asymptomatic
risk of arrhythmia decreases with age
what increases risk
family history of sudden cardiac death
short R-R interval - <250ms
prognosis
sudden death occurs rarely
generally good prognosis
risk of VT or VF
radio-frequency ablation is curative
