Related Subjects: ECG - Wolff Parkinson White syndrome (WPW)
| Wolff-Parkinson White syndrome (WPW)
- 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)
- 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
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
This needs urgent treatment which may include DC shock