Transseptal puncture guided by intracardiac ultrasound to access the left atrium in adult horses

Introduction: Successful 3D mapping and radiofrequency ablation of right atrial tachycardia in horses has become a standardized procedure. Access to the left atrium currently requires a perilous retrograde arterial approach via the carotid artery, which is difficult to achieve using commercially-available catheters. Transseptal puncture (TSP) is a minimally-invasive, routine procedure for left heart catheterizations in human patients, during which the left atrium is accessed from the right atrium by puncturing the fossa ovalis (FO). Our aim was to develop a reproducible procedure to access the left atrium by TSP from a jugular vein approach. Methods: In 12 horses, admitted for euthanasia for non-cardiovascular reasons and after informed owner consent, TSP was performed under general anaesthesia. A cranial approach via the right jugular vein was performed under transthoracic and intracardiac ultrasound guidance. Puncture lesions were evaluated post-mortem. Results: In 11/12 horses, TSP was achieved and evaluated post-mortem. The general approach consisted of over-the-wire positioning of a sheath with dilator against the FO, followed by application of radiofrequency energy on the guidewire tip for FO perforation. The guidewire was advanced into the left atrium, allowing over-the-wire insertion of dilator and sheath. Intracardiac ultrasound was essential to guide TSP (Fig. 1). On post-mortem evaluation, the puncture lesions could be identified as a 2-5mm opening in the FO, located ventral to pulmonary vein ostium III. The over-the-wire insertion of dilator and sheath after guidewire advancement into the left atrium was the most challenging part of the procedure, due to the thick FO and limited catheter support due to the jugular vein approach, and failed in one horse. Conclusions: Via a jugular vein approach, TSP is feasible in horses using intracardiac ultrasound guidance. Clinical relevance: TSP provides minimally-invasive access to the left heart for procedures such as 3D mapping and ablation of left atrial arrhythmias.

Publication year:2022

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