Related Experiment Videos
Ectopic ventricular tachycardia in association with a concealed accessory pathway.
European Journal of Cardiology
|June 1, 1979
Summary
This study identified a concealed accessory pathway causing atrial preexcitation during ventricular tachycardia. Electrophysiological investigation revealed retrograde conduction via the accessory pathway, not the normal system, clarifying tachycardia mechanisms.
Area of Science:
- Clinical Electrophysiology
- Cardiac Electrophysiology
- Cardiology
Background:
- Retrograde conduction to the atria during ventricular tachycardia (VT) is typically attributed to the normal cardiac conduction system.
- Previous studies relied on intracardiac recording techniques to understand retrograde atrial activation during VT.
Observation:
- A patient exhibited 1:1 retrograde conduction with atrial preexcitation during VT, suggesting an unusual pathway.
- Exact atrial capture phenomena confirmed the presence of a concealed accessory pathway.
- Atrioventricular dissociation achieved by atrial overdrive pacing ruled out reentrant VT involving the accessory pathway.
Findings:
- Widely variable H-V intervals with a constant V-A interval during VT suggested anterograde His bundle depolarization after atrial activation via the accessory pathway.
- A prolonged V-H interval during VT supported this hypothesis.
- Analysis of ventricular, atrial, and His bundle electrograms further corroborated the proposed conduction sequence.
Implications:
- This case highlights the importance of detailed electrophysiological studies in diagnosing complex tachycardia mechanisms.
- Understanding accessory pathway involvement is crucial for effective management of ventricular tachycardia.
- The findings underscore the diagnostic value of precise electrophysiological mapping in identifying non-standard conduction routes.