The clinical signs in dogs and cats are a bit different but in general heartworm disease can cause respiratory distress, chronic heart disease / failure and sudden death if left untreated. (georgiaspca.org)
This is a common sign in dogs with heart disease, but it is less commonly seen in cats. (vetmed.tufts.edu)
Children who interact with dogs should learn how to behave around them and how to recognize the warning signs in a dog's body language. (thehappypuppysite.com)