As the disease progresses, horses may show increased breathing efforts especially during exercise and become exercise intolerant. (vetspecialists.com)
If you notice increased breathing effort then see the Management section or take your animal to your veterinarian. (vetmed.tufts.edu)
Early detection of heart disease in cats can be even more difficult to detect for typically they do not cough with cardiac disease, but will display an increased breathing effort. (cccvetservice.com)