Last week, we defined heart failure as an inability of the heart to provide (by pumping) adequate circulation to meet the needs of the cells, tissues and organs of the body. We promised to discuss left side and right side heart failures.
Left heart failure
You remember we had said at the beginning, when we were discussing the basics of the heart function and blood circulation (August 14), that the heart is made up of four chambers – the left and right top chambers (auricles) and the left and right bottom chambers (ventricles). When the left bottom chamber begins to fail, pressure builds up in the blood circulation relative to the lungs. The consequence is blood congestion in the lungs, which results in a continuous accumulation of fluid in the (air sacs of the) lung. As the problem progresses, the animal has so much fluid in the lungs that it begins to cough up a bubbly, red (blood contaminated) fluid. In a situation where there is fluid in the lungs, the animal would obviously not be able to inhale enough air (oxygen) into the lungs. When an inadequate amount of oxygen reaches the cells/tissues/organs, then their functions become compromised and fail.
The early symptoms of a failure of the left ventricle is shortness of breath and a show of tiredness after only a bit of exercise. Later, the dog begins to cough after the least bit of excitement or physical movement. Very often, the food intake remains normal, yet the dog loses condition and he exhibits unthriftiness, apathy and lethargy. His coat loses its sheen and becomes dry to the touch. There is weight loss and the animal becomes emaciated (Guyanese say ‘mager‘). The muscles on his forehead and legs waste away. His ribs and hip bones and the bones of his spinal column (‘backbone‘) begin to protrude.
As the condition advances, the animal exhibits even more respiratory distress (the breathing is obviously laboured). When he sits, his front legs (elbows) are spread apart and he stretches his head forward – all in an effort to ease the pressure on his lungs and to assist them in taking in more air. I have seen dogs, in extreme cases, not wanting to lie down; they try to sleep while sitting up. The pulse is rapid, weak and even irregular. If you put your ear on the chest area, you may be able to detect a vibration, a turbulence, a buzzing over the heart.
When the condition is reaching the point of irreversibility, the dog begins to faint (lose consciousness). Owners think the dog is getting a fit (seizure).
In all of this, the owner has to understand that what is happening is that, because of the left side heart failure, blood volume/mass is increasing in the lungs. This makes the lungs relatively heavy (blood weighs more than air), and, because of gravity, all of this heavy fluid is sinking to the bottom of the lungs and compressing them. That in turn negatively influences breathing.
The animal needs air (oxygen) and is not getting it. The dog begins to turn blue (cyanosis). This bluish tinge is seen on the tongue, gums and inside of the mouth. If this lack of oxygen continues, the work of respiration (breathing) is increased and minimal exertion fatigues the animal. Actually, at this stage, one can hear a ‘crackling‘ sound as the airways close and open during breathing.
I should mention, just to show how serious this ailment is, that because of the increased pressure in the blood vessels in the lung, serum from the blood in the capillaries will also ooze into the lung (edema), causing the lungs to become heavier still. Worst of all, if the pressure increases too much, the left side atrium (top chamber) may tear. The dog will collapse and death is imminent.
Next week, we will deal with the right side heart failure and the general treatment of heart failure.
Please implement disease preventative measures (vaccinations, routine dewormings, monthly anti-heartworm medication, etc) and adopt-a-pet from the GSPCA’s Animal Clinic and Shelter at Robb Street and Orange Walk, if you have the wherewithal to care well for the animals. Do not stray your unwanted pets, take them to the GSPCA’s Clinic and Shelter instead. If you do not wish your pet to have puppies or kittens, you may exploit the GSPCA’s free spay and neutering programme. If you see anyone being cruel to an animal, or if you need any technical information, please get in touch with the Clinic and Shelter by calling 226-4237.