Generally, the vet will start with a fecal sample examination to rule out parasites and some blood work to rule out pancreatic, liver or other systemic disease as the cause. (2ndchance.info)
An adult - onset disease is considered rare, and when it does occur, usually is a result of compromised immunity associated with other systemic diseases like Cushing's disease or cancer. (thesprucepets.com)
Since dog heart patients are prone to various other systemic diseases due to weakened immunity, remedies and / or medications should be used regularly for strengthened immunity such as Immunity and Liver Support. (dog-health-handbook.com)