This is a case I saw in the ED. This case has been deliberately altered to protect the identity of the patient:
28 y/o patient presents to the ED after sustaining blunt trauma to the chest. An EKG is ordered as part of her workup:
Upon further questioning, the patient endorses periods of palpitations over the past couple of months where her “heart was racing”. She denies chest pain, shortness of breath, dizziness, or syncope with these episodes. What’s the diagnosis?
Diagnosis: WPW (Wolf-Parkinson White Syndrome)
- WPW is a syndrome of intermittent tachycardia caused by an accessory pathway that bypasses the AV node.
- Characteristic EKG findings are shortened PR interval, and prolonged QRS (“delta wave”).
- Prevalence of EKG findings is 0.25% of the population, with 1-2% of those patients being symptomatic (tachyarrhythmias).
- Most symptomatic patients will presents with palpitations, with syncope and sudden death occurring much less frequently.
- Treatment is typically reserved for symptomatic patients and involves ablation of the accessory pathway.
Acute treatment of tachyarrthymias:
- Hemodynamically unstable: Cardioversion
- Orthodromic conduction (“normal” pathway; through the AV node with retrograde through the accessory pathway): This will typically be narrow complex. Treat like any other SVT (vagal maneuvers, AV nodal blockade).
- Antidromic conduction (through the accessory pathway with retrograde flow through the AV node): This will typically be wide complex. Unless it is definitively known to be antidromic, treat like any other wide complex QRS tachycardia. Drug of choice is procainamide.
- Atrial fibrillation with pre-excitation (WPW): AV nodal blocking agents are contraindicated, as this will conduct all atrial impulses down the accessory pathway, increasing the heart rate and potentially making your patient unstable. Drug of choice is ibutilide or procainamide.
Case conclusion: Cardiology came to see the patient. Since there was no history of syncope or sudden cardiac death in the family, she was referred for outpatient follow up and possible ablation.