General

• Do not ablate without making a diagnosis
• Do not ablate without mapping completely
• Do not ablate unless you are sure you can recognize and avoid AV block
• Except specific situations, high power ablation does not succeed where low power fails
• Do not ablate for cosmetic reasons

AVNRT

Left sided ablation

VA block during ablation

Accessory pathways

RF parameters to identify effective ablation

Safest ablation is the one that you avoid !

Young male. preexcitation and atypical symptoms

Atrial S1S2 - 600/290 ms

Parahisian pacing

AF induced

Young boy with preexcitation

Mapping approaches - Rhythm

Mapping approaches

• Earliest ventricular activation during maximum preexcitation with atrial pacing *
• Earliest atrial activation during ventricular pacing *
• Earliest atrial activation during orthodromic reentrant tachycardia
• Intermediate preexcitation during sinus rhythm / slow pacing

Septal pathways - Ablate during tachycardia

Left sided pathways - Entrain and ablate

Unipolar EGM

Mapping and ablating in AF

Young male, RHD MS with left sided AP, preexcited AF

Mapping during AF

Ablation during AF

Using the "bump"

Pathway slant

Implications

• Map for earliest A, not shortest VA
• Atrial and ventricular insertions may not correspond
• May be preferable to ablate medial to atrial insertion, where AP potential is observed

LA - CS potentials

Endocardial AP

Epicardial AP

Unusual locations

Female with left sided AP

A-V separated in CS

LAA pathway

CS Diverticulum

Preexcited AF - note leads II and V6

Venogram

Ablation at ventricular insertion

Successful location at neck with CSE potential

Atrial tachycardia

Activation mapping

Summary

• AVNRT - Ablation within CS / left sided ablation
• AVNRT - VA block in some atypical AVNRT
• AT - Activation mapping. P onset in relation to fixed reference
• AP - Dont ablate when not needed
• AP - Choose rhythm to map and ablate carefully
• AP - When mapping for atrial insertion, map like AT constrained to the annulus
• AP - When mapping the ventricular insertion, Use unipolar EGMs
• Mechanical bump can help to map
• Consider unusual locations - appendages / away from annulus / within CS