The pets used are common, and are synonymous with vets. The heart is a sign of care. The care the owners have for their pets and the care that the pets recieve when they are getting treatment. There is also a nice use of negative space in the heart. It's the tail of the cat and also completes the heart shape.

The dog is showing a paw which is also another way that pets show they are hurt or need attention.

The pets are looking upwards, to suggest that they are looking to their owners for help.