Is lamotrigine (antiepileptic medication) safe to use in a patient with a history of supraventricular tachycardia (SVT) and Wolff-Parkinson-White (WPW) syndrome, who has undergone two ablation procedures?

Lamotrigine Safety in WPW Syndrome Post-Ablation

Lamotrigine is safe to use in patients with a history of WPW syndrome who have undergone successful ablation procedures, as lamotrigine does not affect cardiac conduction through accessory pathways or the AV node and is not listed among contraindicated medications for WPW syndrome.

Cardiac Safety Profile of Lamotrigine

• Lamotrigine does not alter AV nodal conduction or accessory pathway conduction properties, distinguishing it from medications that are contraindicated in WPW syndrome 1
• The medications specifically contraindicated in WPW syndrome include AV nodal blocking agents (beta-blockers, non-dihydropyridine calcium channel blockers like verapamil and diltiazem, digoxin, and adenosine) because they can accelerate conduction through the accessory pathway during atrial fibrillation and precipitate ventricular fibrillation 2, 1
• No cardiac conduction warnings or contraindications related to WPW syndrome appear in the FDA labeling for lamotrigine 3

Post-Ablation Considerations

• After successful catheter ablation of accessory pathways, the risk of life-threatening arrhythmias is effectively eliminated, with success rates of 93-98.5% 1
• Following successful ablation, patients no longer have the anatomic substrate (accessory pathway) that creates the risk for rapid ventricular rates during atrial fibrillation 2
• In this patient with two prior ablation procedures, the primary concern would be whether the accessory pathway was successfully eliminated, not the use of lamotrigine itself

Important Clinical Caveats

• Verify ablation success through documentation showing absence of pre-excitation on ECG and no inducible arrhythmias during post-procedure testing 1, 4
• Be aware that approximately 5-8% of patients may experience recurrence of accessory pathway conduction after ablation, which would require repeat evaluation 1, 5
• Some patients (39%) continue to experience palpitations after successful ablation due to other arrhythmias (atrial fibrillation, premature beats) rather than WPW recurrence 5
• If there is any concern about ablation failure or pathway recurrence, obtain a current ECG to assess for pre-excitation pattern before initiating lamotrigine 1

Medications to Avoid in Active WPW

• The American College of Cardiology explicitly contraindicates intravenous beta-blockers, calcium channel blockers, digoxin, and adenosine in patients with active WPW and pre-excited atrial fibrillation (Class III recommendation) 1
• These restrictions apply to patients with functioning accessory pathways, not to those with successfully ablated pathways 2