Ultrasonographic Identification of the Pulmonary Veins in Adult Horses

Abstract

Reasons for performing studyIn man, pulmonary veins (PV) are of major importance in atrial fibrillation pathophysiology as ectopy often originates in atrial myocardial sleeves extending in the PV wall. In addition, PV size on ultrasound is used to assess left atrial volume overload. In horses, PV anatomy and ultrasound have hardly been studied.ObjectivesTo study PV anatomy and establish a standard approach for echocardiographic identification of the PV from a right and left parasternal view.Study designAnatomical and echocardiographic description.MethodsFirstly, post mortem left atrial and PV silicone corrosion casts were made in 10 horses to investigate normal PV anatomy. Secondly, left and right parasternal ultrasound images and silicone casts were made in 3 horses, to compare images and casts.ResultsFour major PV ostia were identified on the casts, draining specific lung areas. From a right parasternal longitudinal view, ostium III was identified between the right atrial wall and right pulmonary artery, and ostium II left‐dorsal to it. From a left parasternal oblique short‐axis view, ostium III, its antrum and side‐branches were used as anatomical landmarks (adjacent to the right atrial wall). Slightly more caudal, ostium II was visualised with, in one horse, its antrum and 2 branches. Ostium I was only seen in one horse, slightly ventral to ostium II. Ostium IV was always identified in cross‐section on a left short‐axis view, left to the pulmonary artery bifurcation.ConclusionsA standard echocardiographic approach allows identification of pulmonary veins in adult horses. Left oblique and short axis views were superior although right long‐axis views also showed ostiums II and III. These data allow reference values to be established for pulmonary venous size and flow, and to investigate new treatment strategies for atrial fibrillation.Ethical animal research: Post mortem study with owner's informed consent; ultrasound with owner's informed consent. Study performed following the local ethical guidelines. Source of funding: Ghent University (institutional). Competing interests: None declared.