Key Points
- To determine the electrophysiological mechanism responsible for an unusual initial V-A-A-V activation pattern during the induction of a long RP supraventricular tachycardia.
- Conducted an invasive electrophysiologic study and catheter ablation in a 52-year-old woman with recurrent paroxysmal supraventricular tachycardia using programmed ventricular pacing and isoproterenol infusion.
- Mapped retrograde atrial activation sequences and delivered premature ventricular extrastimuli during His-bundle refractoriness to evaluate accessory pathway conduction and differential diagnostic pacing responses.
- Ventricular pacing reproducibly induced long RP tachycardia with an initial V-A-A-V sequence, where the first atrial activation traveled over a fast pathway near the His bundle and the second traveled over a slow pathway near the coronary sinus ostium.
- Dual induction patterns showing both V-A-A-V and V-A-V responses confirmed atypical fast-slow atrioventricular nodal reentrant tachycardia rather than atrial tachycardia.
- Radiofrequency catheter ablation targeted to the slow pathway near the coronary sinus ostium induced junctional rhythm and successfully eliminated tachycardia inducibility.
Structured PICO
PPopulationA 52-year-old woman with a history of multiple episodes of paroxysmal supraventricular tachycardia.
IInterventionElectrophysiologic studies and radiofrequency catheter ablation of a slow pathway in the posteroseptal right atrium.
OOutcomeElimination of inducible tachycardia.
This case demonstrates that a 'V-A-A-V' response observed upon cessation of ventricular pacing is not definitive electrophysiological proof of atrial tachycardia and can occur in atypical AVNRT.