Blood circulatory system General Comments

The pulse is really an expression of the heartbeat. The way you take the pulse in humans (feeling the wrist or the pulsation of the big vessels running along the neck area) is not the same with dogs.

With your dog standing (or lying on his back), you can feel the pulse by placing two fingers in the inside thigh area (groin), where the dog’s leg joins the body. You would be feeling the pulsation in the femoral artery. There is another way which can be used, if the dog is prostrate. You can press the rib cage over the heart area. If the dog can stand you can feel the chest pulse just below the elbow joint.

In passing, I should mention that if the heart is enlarged, or in some way diseased, you may be able to detect a vibration or a buzz over the chest area.

The pulse rate is equal to the rate of heartbeats. One usually counts the number of pulsations per minute. That, therefore, would be the same as the number of heart beats per minute. Large dogs usually have fewer heartbeats per minute than smaller dogs. Puppies would have the fastest pulse rates. Well conditioned working dogs (hunting dogs, police dogs) tend to have a slower pulse rate. The average pulse rate is between 60 (70) – 120 (130) beats per minute.

The pulse should be strong, steady and regular. A slight alteration in rate as your dog breathes in and out is normal. An exceedingly fast pulse may indicate fever, anaemia, blood loss, dehydration, shock, infection, over-exertion, heatstroke, or heart (and lung) disease. A very slow pulse can indicate heart disease, pressure on the brain, or an advanced morbid condition causing collapse of the circulation.

An erratic, irregular or disordered pulse suggests a serious cardiac condition. When untreated, it can cause the heart to fail.

Various drugs your dog might be taking can affect the rate and rhythm of the heart.

 Heart sounds

Veterinarians use a stethoscope to listen to the heart. You can listen to the heart by placing your ear against the chest. Or you can hold an ordinary drinking glass over the heart and listen through the open end.

The normal heartbeat is divided into two separate sounds. The first is a LUB, followed by a slight pause, and then a DUB. Put together the sound is LUB-DUB …LUB-DUB… in a steady, regular manner.

Murmurs

Murmurs are caused by turbulence in the flow of blood through the heart; for example, if the heart chambers contain canine heartworm.

Serious murmurs can also be due to heart valve disease or birth defects. Anaemia can also result in a heart murmur.

Not all murmurs are serious. Some are called functional – that is, there is no disease, just a normal degree of turbulence. Your veterinarian can determine whether a murmur is serious or of little consequence.

Thrills

A thrill is caused by turbulence of such a degree that you can feel a buzzing or vibration over the heart. It suggests an obstruction to the flow of blood – for example, a narrowed valve, or a hole in the heart, or a heartworm infestation.

Circulation

(The text relies heavily on a Vet Handbook authored by Drs Carlson and Giffin)

If you examine the gums or the inner eyelids, you can gain a clue to the adequacy of your dog’s blood circulation. A deep pink colour is a sign of adequate circulation.

The quality of the circulation can easily be tested by noting the time it takes for the tissue to pink-up after the gums have been pressed firmly with a finger.  With normal circulation, the response is immediate (one second or less).

A delay of two seconds suggests poor circulation. When the finger impression on the gum remains pale for three seconds or longer, the dog is likely to be in shock.

A gray or bluish tinge to the mucus membranes of the lips and tongue is a sign of insufficient oxygen in the blood (cyanosis). It can be seen in heart and lung failure.

Next week, we’ll discuss the issue 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.

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