Fainting
– When blood is not pumped correctly, this can cause lapses where the dog is not receiving enough blood flow and the dog can faint.
The fainting will happen for a few seconds to a few minutes depending on how fast the dog’s heart corrects itself.
It should be noted, that for young puppies, particularly under the age of 6 months, fainting can be the sign of hypoglycemia...a rapid, dangerous drop in blood sugar levels (treated by rubbing Karo syrup directly onto the pup's gums for rapid transport into the bloodstream and then bringing him or her to the closest vet or animal hospital)....Therefore, any collapse or fainting must be treated immediately.
Coughing -
Each case is different. However some Boxer dogs with cardiomyopathy will reach a point where the ventricles of the heart expand. This causes the walls of the heart to become too thin and the heart itself will decline in strength.
Coughing may occur at this point. Owners should not panic if coughing occurs, as it may be something as simple as allergies...However, it is important to have it checked out as soon as possible.