Dogs with CHF or congestive heart failure will often have a difficult time breathing with decreased play activity possible loss of appetite and may even become more irritable. Have your dog checked by a vet to relieve symptoms.
With this condition the heart isn't functioning properly and is overtaxed in trying to circulate the blood. It can become enlarged and murmurs can occur. You will see increased cough.
Some symptoms of a weakening heart is coughing, Shortness of breath, Difficult breathing, weight loss and fatigue. Unfortunately there are many causes of Congestive heart failure for dogs and it is not uncommon.