Caudal vena cava isolation using ablation index-guided radiofrequency catheter ablation (CARTO™ 3) to treat sustained atrial tachycardia in horses.
Authors: Buschmann Eva, Van Steenkiste Glenn, Vernemmen Ingrid, Demeyere Marie, Schauvliege Stijn, Decloedt Annelies, van Loon Gunther
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary: Ablation Index–Guided Treatment of Atrial Tachycardia in Horses Sustained atrial tachycardia in horses frequently originates from myocardial sleeves within the caudal vena cava, yet traditional ablation approaches have yielded variable long-term outcomes. This Belgian team evaluated whether ablation index–guided radiofrequency catheter ablation (RFCA)—a technique that optimises lesion quality by integrating power delivery, duration and contact force into a single metric—could improve treatment efficacy in ten horses with sustained AT. Three-dimensional electro-anatomical mapping revealed a macro-reentry circuit in the caudomedial right atrium in all cases; isolation of the caudal vena cava required a mean of 17 ablation applications, targeting an ablation index of 400–450, delivered at median power of 35 W for 20 seconds with contact force of 10 g. All ten horses converted to sinus rhythm immediately post-ablation, and critically, none experienced arrhythmia recurrence during follow-up intervals of 9–37 months. For practitioners managing equine arrhythmias, these findings suggest that ablation index guidance represents a significant advance over conventional endpoint criteria (such as electrogram elimination alone), potentially reducing both procedure complexity and recurrence risk through more consistent, quantifiable lesion creation at the proven arrhythmogenic substrate.
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Practical Takeaways
- •Ablation index-guided RFCA is a feasible and effective treatment option for horses with sustained atrial tachycardia, offering permanent resolution without recurrence in this cohort
- •This advanced electrophysiological technique requires specialized equipment (CARTO 3 mapping system) and expertise, making it suitable for referral centers treating refractory arrhythmias
- •Caudal vena cava isolation should be considered as a definitive intervention when sustained AT is confirmed on mapping, rather than relying on medical management alone
Key Findings
- •Three-dimensional electro-anatomical mapping identified macro-reentry circuits in the caudomedial right atrium in all 10 horses with sustained AT
- •Ablation index-guided radiofrequency catheter ablation successfully isolated the caudal vena cava myocardial sleeves using a median of 17±7 applications per horse
- •Sinus rhythm was restored in all 10 horses (100% acute success rate) with zero recurrence over 9-37 months of follow-up
- •Median ablation index of 436 was achieved with median maximum power of 35W for 20 seconds duration, demonstrating efficient lesion creation