ARRHYTHMIAS-WPW SYNDROME

SUMMARY

1. PR interval is < 0.12 sec, total QRS is > 0.12 sec because of the fusion between the impulse that uses the normal conduction system and that which uses the abnormal (accessory) pathway, which bypasses the AV node.

2. This bypass tract (accessory pathway) conducts faster than the AV node; therefore, a portion of the electrical current reaches the ventricle sooner (the delta wave on the ECG) and preexcites the ventricle.

3. Presentation: orthodromic AVRT (narrow QRS), antidromic AVRT (wide QRS), AF (irregularly irregular wide QRS).

MANAGEMENT
4. Conservative in asymptomatic individuals; those with symptoms can be treated with vagal manouvers, adenosine & CCB.

5. Never treat with digoxin, verapamil, beta-blockers.These would preferentially enhance conduction across the acessory pathway leading to VT.

6. Treat AF in in WPW with IV procainamide, ibutilide, or amiodarone. Shock in haemodynamic compromise.

7. assoc. with with risk of sudden death, so RF ablation is the long-term option.

Reference(s)

Wilkinson, I., Furmedge, D. and Sinharay, R. (2017). Oxford handbook of clinical medicine. Oxford: Oxford University Press. Get it on Amazon.
Feather, A., Randall, D. and Waterhouse, M. (2020). Kumar And Clark’s Clinical Medicine. 10th ed. S.L.: Elsevier Health Sciences. Get it on Amazon.
Hannaman, R. A., Bullock, L., Hatchell, C. A., & Yoffe, M. (2016). Internal medicine review core curriculum, 2017-2018. CO Springs, CO: MedStudy.
Therapeutic Guidelines. Melbourne: Therapeutic Guidelines Limited. https://www.tg.org.au [Accessed 2021].