The clinical signs of heart disease include: noticing that your dog is slowing down, having less tolerance to exercise, more rapid breathing, coughing, weakness, and collapse episodes.  Routine physical examinations with your primary care veterinarian can also help find underlying cardiac issues if signs of a heart murmur, other abnormal heart sounds, or an irregular heart rhythm are present.  If signs of heart disease are noted and are related to nutritional issues, we have found some dogs will have a reversal of their cardiac changes with adjustments in the diet and taurine supplementation.