The ECG (Figure 3 shown on page 16) is from a 35-year-old male who presents with paroxysmal tachycardia.
e) What condition is demonstrated? Describe the characteristic features. (30% marks)
f) What would be the possible pharmacological options if his tachycardia were to recur?
e) Wolf-Parkinson-White syndrome
• short PR interval, less than 3 small squares (120 ms)
• slurred upstroke to the QRS indicating pre-excitation (delta wave)
• broad QRS
• secondary ST and T wave changes
f) IV procainamide or amiodarone is preferred, but any class Ia, class Ic, or class III antiarrhythmic can be used
The ECG features of WPS are:
- The PR interval is short (less than 0.12 seconds)
- There is a delta wave (a slurred upstroke of the QRS complex)
- Wide QRS (because the delta wave widens it)
- ST Segment and T wave discordant changes: T waves point in the opposite direction to the QRS.
- Pseudo-Q waves: negatively deflected delta waves in the inferior/anterior leads
- prominent R wave in V1-3 (mimicking posterior infarction).
Management of SVT in this condition:
- Vagal manoeuvres
- AVOID AV node blocking drugs such as adenosine, digoxin, beta blockers and calcium channel blockers
- Procainamide, ibutilide or amiodarone are the only antiarrhytmics useful in WPW
- DC synchronised cardioversion
Flecainide or propafenone are used in long term management. Amiodarone also OK - but the side effect profile in long term use is not very nice for younger patients.
|Arrhythmia||Drugs contraindicated||Drugs Recommended|
In case you were wondering, WPW patients die sudden cardiac deaths when they develop AF, which is conducted rapidly and erratically through their aberrant pathway, producing VF (Obeyeseker et al, 2012)
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and, somewhat more recently...
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