ECG - Wolff Parkinson White syndrome (WPW)

Related Subjects: ECG - Wolff Parkinson White syndrome (WPW) | Wolff-Parkinson White syndrome (WPW)

ECG Findings

• Rate: most often 60-100 beats/min as usual rhythm is sinus
• Rhythm: normal sinus except during pre-excitation tachycardia
• PR: shorter since conduction through accessory pathway is faster than through AV node
• P waves: normal conformation
• QRS complex: classically distorted by delta wave (upwards deflection of QRS is slurred)

Wolff-Parkinson-White syndrome

• Electrocardiograms from patients presenting with WPW demonstrate a group of characteristic findings frequently associated with paroxysmal tachycardias and atrial fibrillation.
• In WPW, accessory pathways of accelerated ventricular impulse formation lead to the development of delta waves.
• These waves resemble pathological Q waves and represent initial slurring of the QRS complex as a result of early ventricular depolarization through this accessory pathway (see lead II, V1 and V6 - arrow below).
• As a result, the PR interval is shortened to less than 0.12 seconds and the QRS direction is altered (lead III), while its duration is extended to greater than Wolff-Parkinson-White syndrome 0.10 seconds.
• Secondary T wave anomalies resulting from abnormal ventricular repolarization are often demonstrated (leads II, III, V2, V3 and V4).

Typical WPW ECG: short PR and delta wave

AVRT Orthodromic

This needs urgent treatment usually with vagal manoeuvres and adenosine, Rarely may need DC shock

AF with conduction down aberrant pathway: Danger ! Risk of VF

WPW

This needs urgent treatment which may include DC shock