1. 80 yr old lady Normal Numerous episodes of palpitations (near- incessant) over many years, drug-refractory Inputs from Chandrashekhar and Aditya Kapoor

2. As the EP procedure began…D/D? Long RP tachycardia, narrow P : Atypical AVNRT, Coumel (PJRT), AT arising close to CS OS

3. What next? Bring in His-refractory VPD and look for atrial advancement with reset/delay/tachy termination- indicates Coumel. Next do incremental V pacing at a rate 30 msecs faster than the tachycardia and look for VA dissociation. If VA conduction, after stopping V pacing look for the evidence of VAAV or VAV response VAAV response indicates an AT, VAV response indicates it may be either Atypical AVNRT or Coumel. Long VA: CS 7/8 and Hisp a bit early than

4. Tachy induction-comment Induction of a long RP tachycardia during CS pacing without any prolongation of the PR interval

5. Intracardiacs… A during tachy equally early at HIS and CS os (CS78-910). However, not much earlier than P wave onset

6. Analyse- VA conduction appears concentric, long VAERP

7. Adenosine-analyse. Prolongation of the AA interval prior to termination. Terminates with a V: not very helpful…

8. Intracardiacs during adenosine- any further insight? Not really. A-V remains constant, the A-A and V-A prolong prior to termination.

9. Tachy mechanism? Not yet confirmed

10. Overdrive RV pacing during tachy, showing VA dissociation without affecting tachycardia cycle length. Now AT confirmed!

11. Good signal to ablate? Yes: A early…unipolar good Likely site?

12. RF site-LAO 40

13. RF site- RAO 30

14. RF energy- clean early termination. No tachy inducible after this Energy starts here