ECG: WPW Syndrome

PROF .Dr G.SUNDARAMURTY ‘S UNITM6

S.DHANRAJ Ist YEAR PG

HISTORYA 45 YR old female presented with

Difficulty in breathing

Palpitation

Sweating for past 4 hours

ECG

FINDINGSNormal sinus rhythmRate 80 / minAxis normalPR shortened 0.08 secBroad QRS complexQRS duration 0.12 secQTC 0.40 secDelta wave noticed(slurred QRS upstroke)Terminal QRS normalSecondary ST/T changes seen

DIAGNOSISWPW SYNDROME

POSSIBLE PATHWAYS Right posteroseptal anteroseptal

PATHWAYS

HISTORY

Named after three scientists WOLFF PARKINSONWHITE

In the year 1930

DEFINITIONWPW is a electrocardiographic syndrome it is

the expression of anomalous atrio ventricular conduction pathway congenital in origin

This pathway forms a bypass which enables supraventricular impulse to bypass AV node , bundle of HIS and distal conducting system and so activate or pre exite the ventricles

This anomalous bypass, most commonly bundle of kent situated any where along AV node

ECG PRESENTATIONShort PR intervalSlurred initial upstroke of QRS – delta waveRelatively normal , narrow terminal QRS –

main QRS deflectionSlight widening of QRS Secondary STT changes

CARDIAC ACTIVATIONPHASE 1

Atrial activation- normal PHASE 2:

Ventricular pre-exitationsinus activation occurs through both normal ,

anomalous pathwayanomalous pathway lacks AV nodal conduction

delayso sinus impulse conducted at a rapid ratethis enables ventricles to be activated or pre

exited- short PR interval , delta waveFurther activation through normal pathway

PHASE 3:Narrow terminal QRS

OLD CLASSIFICATIONType A

In this type of WPW syndrome, the delta wave and QRS complex are predominantly upright in the precordial leads. The dominant R wave in lead V1 may be misinterpreted as right bundle branch block.

Type BThe delta wave and QRS complex are

predominantly negative in leads V1 and V2 and positive in the other precordial leads, resembling left bundle branch block.

PATHWAY

ORTHODROMICDESCEND- NORMAL PATHWAYASCEND- ACCESSORY PATHWAYIn orthodromic tachycardia, the normal

pathway is used for ventricular depolarization and the accessory tract is used for reentry.

VPC’s can initiate orthodromic tachycardiaOn ECG findings,

the delta wave is absent, QRS complex is normal, P waves are inverted in the inferior and lateral

leads

ANTIDROMICLESS COMMON PATHWAY.DESCEND- ACCESSORY PATHWAY.ASCEND – NORMAL PATHWAYOn ECG findings,

the QRS is wide, which is an exaggeration of the delta wave during sinus rhythm (ie, wide-QRS tachycardia).

Such tachycardias are difficult to differentiate from ventricular tachycardia

PATHWAYS

FIBRES

KENT PATHWAY : ATRIO-VENTRICULAR

JAMES PATHWAY : ATRIO-HIS

MAHAIM PATHWAY: HISO- VENTRICULAR

MAHAIM FIBRE:Orgin- distal to AV nodeEnds in the venricular myocardiumECG:•normal PR interval•delta wavesJAMES FIBRE(LGL SYNDROME)•Origin- atria•Bypass AV node•Ends in bundle of HIS•ECG:•Short PR•Normal QRS

COMPLICATIONTachyarrhythmiaSyncopal attacksSudden cardiac deathComplications of drug therapy (eg,

proarrhythmia, organ toxicity)Complications associated with invasive

procedures and surgeryRecurrence

TREATMENT

ANTIARRYTHMICS– class 1c, 3

RADIOFREQUENCY ABLATION ( TOC)

SURGICAL ABLATION ( OUTDATED)

CAUTIONUsual presentation is SVT

Sudden cadiac death possible

Digoxin, beta blockers,verapamil are contraindicated

Underlying Ebstein’s anomaly, hypertrophic cardiomyopathy should be evaluated

THANK YOU