My Most Educative Case: Slow-Fast AVNRT

Raja Selvaraj
Professor of Cardiology
JIPMER

History

• 30 year old female
• Recurrent palpitations for 8 years
• Three failed ablations over last 6 years

Tachycardia

Sinus rhythm

Plan

• AV junction ablation with pacemaker implant ?
• Medical management
• Slow pathway ablation
• Fast pathway ablation

Summary

• Patient with recurrent short RP tachycardia and failed previous ablations
• No accessory pathway conduction
• Dual AV nodal physiology
• Tachycardia with 1:1 AV, VA -15ms, VAV response and long PPI

Rethink Slow-fast AVNRT

• Reentry using slow pathway as antegrade limb and fast pathway as retrograde limb
• A set of reentrant arrhythmias using fast pathway as the retrograde limb and one of the slow pathways as the antegrade limb

Reset - Why ?

Reset - How to do it

Reset - How I do it

Reset - How I do it

LIE ablation

• Two ablations within CS
• No junctionals
• Dual AV nodal physiology still present
• Tachycardia still inducible

Post ablation

• No AH jump
• No tachycardia inducible

What have I learnt

• AVNRT as a set of different arrhythmias
• Retrograde slow pathway easier to map
• Antegrade slow pathway needs resetting to identify
• May not be required in de novo AVNRT ablation
• But with initial failed ablation, careful study essential

Inferolateral slow pathway

• Identified by reset from endocardial lateral MA
• May also show borderline reset from CS
• Junctional beats usually elicited