Prevalence of left heart contrast with agitated saline contrast echocardiography in healthy resting dogs.

Abstract

INTRODUCTION/OBJECTIVES: Agitated saline contrast echocardiography (ASCE) has traditionally been used to identify the presence of right-to-left intracardiac shunts in dogs. In normal humans, contrast (microbubbles) commonly appears in the left heart following agitated saline contrast injection into a systemic vein via intrapulmonary (IP) shunting. The aim of this study was to determine whether this phenomenon also occurs in dogs. ANIMALS, MATERIALS, AND METHODS: Forty-eight dogs with either a normal echocardiogram or trivial to mild mitral regurgitation were studied. A standard ASCE protocol was used, with each dog lying in right lateral recumbency. RESULTS: Left heart contrast was identified in 37 dogs (77%). STUDY LIMITATIONS: Agitated saline contrast echocardiography was performed only once per dog and under a single condition, and intra-operator and interoperator variability was not assessed. Echocardiography alone cannot completely exclude patent foramen ovale, and stress in the hospital environment may have influenced shunting. CONCLUSIONS: Left heart contrast following ASCE is common in dogs without a right-to-left shunting intracardiac defect. This presumably occurs via intrapulmonary arteriovenous anastomoses.