Morphological evidence of a potential arrhythmogenic substrate in the caudal and cranial vena cava in horses.
Authors: Ibrahim Lara, Buschmann Eva, van Loon Gunther, Cornillie Pieter
Journal: Equine veterinary journal
Summary
# Editorial Summary Atrial arrhythmias remain a significant clinical challenge in equine practice, yet the anatomical substrate underlying these conditions has been incompletely characterised until now. Using three-dimensional electro-anatomical mapping—a sophisticated imaging technique that integrates electrical activity with spatial anatomy—researchers identified specific regions of the caudal vena cava (CaVC), particularly 1–8 cm caudal to the fossa ovalis, as a consistent site of abnormal electrical properties including slow conduction and conduction block in horses with atrial tachycardia. Similar electrophysiological abnormalities were also documented in the cranial vena cava (CrVC), suggesting both venous structures harbour arrhythmogenic potential. These morphological findings provide crucial anatomical context for understanding how atrial arrhythmias initiate and perpetuate in horses, and may explain variable treatment responses when these areas are not adequately addressed during interventional procedures. For clinicians managing horses with recurrent or refractory atrial arrhythmias, recognition of these predilection sites offers a more targeted approach to diagnosis and potential ablation therapy, whilst the identified conduction abnormalities suggest that future preventative or therapeutic strategies might be directed towards stabilising these vulnerable regions.
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Practical Takeaways
- •Horses with atrial arrhythmias may have identifiable anatomical substrate in the vena cava that could guide catheter-based intervention strategies
- •Recognition of the caudal vena cava as an arrhythmogenic predilection site could improve diagnostic and therapeutic approaches to equine cardiac arrhythmias
- •Advanced electro-anatomical mapping techniques may help identify which arrhythmia cases are amenable to interventional procedures versus medical management
Key Findings
- •The medial region of the caudal vena cava 1-8 cm caudal to the fossa ovalis is a predilection site for atrial tachycardia in horses
- •Areas of slow conduction and conduction block identified in the caudal vena cava correlate with arrhythmogenic substrate
- •Slow conduction was also demonstrated in the cranial vena cava, suggesting a potential arrhythmogenic substrate
- •Three-dimensional electro-anatomical mapping identified morphological evidence of cardiac arrhythmia substrate in venous tissue