WPW Syndrome with Oblique Pathway and Underlying LBBB: A Case Insight

WPW Syndrome with Oblique Pathway and Underlying LBBB: A Case Insight Blog

WPW Syndrome with Oblique Pathway and Underlying LBBB: A Case Insight

Category: Electrophysiology | Procedure Type: Radiofrequency Ablation | Condition: WPW Syndrome, Orthodromic Tachycardia, LBBB

Introduction

Wolff–Parkinson–White (WPW) syndrome presents a unique challenge in cardiac electrophysiology, especially when associated with complex accessory pathways. This case highlights a patient with WPW, exhibiting an oblique left lateral pathway, who developed spontaneous orthodromic tachycardia and post-ablation left bundle branch block (LBBB).

Baseline ECG Findings

The initial ECG revealed:

  • Classic WPW features: short PR interval and delta waves

  • Positive V1 indicating left lateral accessory pathway

Baseline ECG showing delta waves and V1 positivity

These findings pointed toward a left-sided accessory pathway, which was further confirmed during electrophysiological (EP) study.

Electrophysiological Study & Tachycardia Induction

During the EP study:

  • Orthodromic AVRT was induced spontaneously

  • CS 1,2 activation was early, reinforcing the left lateral insertion site of the accessory pathway Diagnosis: Oblique left lateral pathway

achycardia tracing with early CS 1,2 signals

This confirmed the anterograde conduction via AV node and retrograde via the accessory pathway, typical of orthodromic reentry.

Ablation Procedure

The team proceeded with radiofrequency ablation (RFA) targeting the oblique pathway using multiple fluoroscopic views for precision.

  • Oblique course required mapping from multiple angles to avoid missing the pathway

  • Ablation was successful within 4 seconds of RF application

Immediate Post-Ablation Outcome

Once tachycardia was terminated:

  • Patient developed LBBB morphology on surface ECG

  • This was presumed to be rate-related or transient conduction disturbance

Final EP Observations

  • No VA conduction at 500 ms

  • No inducible tachycardia on atrial pacing

  • AH and HV intervals remained within borderline limits

  • No recurrence of symptoms post-ablation

Conclusion

This case underscores the importance of:

  • Careful mapping of oblique accessory pathways

  • Recognizing spontaneous tachycardia patterns

  • Monitoring conduction system post-ablation for changes like LBBB

The successful ablation and non-inducibility of tachycardia highlight the efficacy of EP intervention in complex WPW cases with atypical pathways.