Anatomy and terminology
Triangle of Koch
Risk of AV block
Where do you get AV block on the septum
Pediatric registry
Schaffer MS, Silka MJ, Ross BA, Kugler JD. Inadvertent atrioventricular block during radiofrequency catheter ablation. Results of the Pediatric Radiofrequency Ablation Registry. Pediatric Electrophysiology Society. Circulation. 1996 Dec 15;94(12):3214-20.
Ablation over HB and risk of AV block
Xue Y, … Kuck KH, Yen Ho S, Ouyang F. Experimental, Pathologic, and Clinical Findings of Radiofrequency Catheter Ablation of Para-Hisian Region From the Right Ventricle in Dogs and Humans. Circ Arrhythm Electrophysiol. 2017 Jun;10(6):e005207. doi: 10.1161/CIRCEP.116.00520728630174.
So how do you avoid AV block ?
- Awareness of risk
- Ability to monitor AV conduction during ablation
- Assess for His bundle capture
Mapping approaches
Mapping retrograde
Mapping antegrade
Target
Slant and isolated potential
Otomo K …Jackman WM. Reversing the direction of paced ventricular and atrial wavefronts reveals an oblique course in accessory AV pathways and improves localization for catheter ablation. Circulation. 2001 Jul 31;104(5):550-6. doi: 10.1161/hc3001.093499.
Anteroseptal pathways
Stability
- Long sheath
- IJV approach
Curve
Ablation during ORT
Mapping echo beats
Ablation from NCC
Optimal signal
Suleiman M, Brady PA, Asirvatham SJ, Friedman PA, Munger TM. The noncoronary cusp as a site for successful ablation of accessory pathways: electrogram characteristics in three cases. J Cardiovasc Electrophysiol. 2011 Feb;22(2):203-9. doi: 10.1111/j.1540-8167.2010.01811.x.
Midseptal pathways
ECG
Cryoablation
- Reversible cryomapping makes it safer
- Consider when risk of AV block high
- Especially in children
Cryoablation vs RF ablation
- Acute success similar (93% vs. 87%)
- No AV block
- Less recurrence (14% vs. 30%)
- Less mechanical trauma (6% vs. 20%)
Dos Santos Sousa IB, Chokr MO, Melo SL, Pisani CF, Hardy CA, de Moura LG, Sacilotto L, Wu TC, Darrieux FCC, Scanavacca MI. Comparison between cryotherapy and radiofrequency energy sources for parahisian accessory pathway percutaneous ablation. J Interv Card Electrophysiol. 2024 Dec;67(9):1981-1991. doi: 10.1007/s10840-024-01841-8. Epub 2024 Jun 4. PMID: 38833098.
Summary
- Subset of accessory pathways characterised by high risk of AV block
- Understanding of anatomy and risk of AV block at different areas
- Ablate in a manner that AV block can be identified
- Cryoablation may be preferred in children and in midseptal pathways