When is a heartworm positive dog not treated?

If the risks associated with treatment outweigh the risks associated with leaving the infection or when an owner opts not to treat for whatever reason. Diagnostic testing including blood chemistries and chest x-rays should be performed prior to treating adult heartworms and then the results from these tests are reviewed by the veterinarian to determine whether there is an issue that makes treatment of heartworms an unrealistic or sufficiently hazardous option as to recommend not treating.