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

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.