SAQ 162 – Cardiology – atrial fibrillation with Wolff-Parkinson-White

Question 5. atrial fibrillation with Wolff-Parkinson-White.

a. ECG abnormalities

• Short PR interval.
• Broad QRS complexes with delta waves, consistent with Wolff-Parkinson-White syndrome.
• Secondary Q waves, ST depression, and/or T-wave inversion.

b. Ongoing management

• Apply defibrillation pads in an anterior-posterior position and prepare the defibrillator.
• Use a rhythm-control strategy: IV flecainide if structural heart disease and coronary disease are excluded, or proceed to procedural sedation and synchronised cardioversion.
• If instability develops, perform immediate synchronised cardioversion.
• Use synchronised biphasic shock, escalating energy if required.
• Optimise potassium and magnesium and identify reversible contributors.
• Obtain urgent cardiology review and admit to a monitored bed.

c. Justification

• Atrial fibrillation in WPW can rapidly progress to ventricular fibrillation.
• Rhythm control is required; AV nodal rate-control drugs may be dangerous.
• Current haemodynamic stability does not eliminate the risk of sudden deterioration.
• Electrical cardioversion is preferred if structural normality and coronary status are unknown.