LAUSR

BACKGROUND Ultra-high-density cardiac mapping allows very accurate characterisation of atrial and ventricular electrophysiology and activation timing. OBJECTIVE To describe the technique and evaluate the feasibility of magnetic electro-anatomical mapping of the equine heart. STUDY DESIGN In vivo experimental method development. METHODS A mapping system using an 8.5 F bidirectional deflectable catheter with a deployable mini-basket (3-22 mm) containing 64 electrodes divided over 8 splines was evaluated. Based upon predefined beat acceptance criteria, the system automatically acquires endocardial electrograms and catheter location information. Electro-anatomical maps were acquired in 4 horses in sinus rhythm under general anaesthesia. RESULTS All endocardial areas within each chamber could be reached. Access to the left atrium required the use of a deflectable sheath. With the exception of the left atrial map of horse 1, all 4 chambers in all 4 horses could be mapped. Optimisation of the beat acceptance criteria led to a reduction in manual correction of the automatically accepted beats from 13.1% in the first horse to 0.4% of the beats in the last horse. MAIN LIMITATIONS Only a limited number of horses were included in the study. CONCLUSION Ultra-high-density 3D electro-anatomical mapping is feasible in adult horses and is a promising tool for electrophysiological research and characterisation of complex arrhythmias.