what are the symptoms of the final stages of congestive heart failure in dogs?
['Excessive tiredness or sleepiness.', 'A frequent cough.', 'Lack of appetite.', 'Fainting spells.', 'Difficulty sleeping, especially for dogs who sleep on their sides.', 'Lethargy or reduced exercise or inability to exercise at all.', 'Fluid in the abdomen or a swollen stomach.']