Lucky an 11 year old male terrier with heart disease.

Lucky had always been a typical terrier – an active, energetic dog. He had been healthy over the years apart from a few minor illnesses. He had a bout of kennel cough when he was young, which caused him to cough for a few weeks, but he made a full recovery. A few years later, he suffered from a slipped disc in his back, which slowed him up for a while, but again, he soon bounced back to normal.

Recently he developed a mild cough. At first, it seemed as if it might be a recurrence of kennel cough, but after a few weeks, the cough persisted, and Dymphna brought Lucky to see me. At this stage, he was only coughing a few times a day, but it was always worse after exercise.

When I examined Lucky, at first he seemed like a vibrant, healthy dog. His coat was glossy, his eyes were bright, and his muscles were well-toned. But when I put my stethoscope to his chest, it was obvious that there was something amiss. He had a loud heart murmur that had not been present in previous years when I had examined him. And his heart-beat was racing along faster than it ought to be, at around 160 beats per minute.

The dictionary defines the word “murmur” as “a quiet, continuous sound, e.g. of running water”. This is an apt description of what I could hear with the stethoscope. A healthy heart sounds like two fingers being drummed on a table surface. In Lucky’s case, the normal double-beat of his heart had a hissing sound in the background, like a tap being turned on and off.

A mild heart murmur is a common incidental finding in some dogs, and it does not always mean that there is a significant problem. But this was a loud heart murmur, and along with the rapid heart rate, it was a sign that his heart might not be as healthy as it should be. I then examined the gums in his mouth, which seemed to be a good, healthy pink colour. When I pressed my finger tip onto the gums, they blanched white, and it took around two seconds for the normal pink colour to come back. This was a sign that Lucky’s circulation was not as healthy as it should be. This test is known as the “capillary refill time”, and in a healthy dog, the normal colour floods back almost instantaneously. When the gums are pressed, if the pink colour does not rush back in less than one second, it is a sign of poor circulation.

My initial examination showed that Lucky was suffering from signs of a heart problem, but to give him the best possible treatment, I needed to find out exactly what was wrong with his heart. The first stage of the process was to take some x-ray pictures of his chest. These confirmed what I had suspected – Lucky’s heart was very enlarged. The heart is a type of muscle, and like any muscle elsewhere in the body, if it does more work, it gets bigger. When a dog has a heart murmur, this often indicates a leaky heart valve, and so the heart has to work harder to keep up with the normal demands of the body. As a result of this extra effort, the heart literally grows bigger. The x-rays gave me definite proof that Lucky’s cough was caused by a serious, problem with his heart.

The next stage of the investigation was to carry out an ultrasound examination. Fur was clipped from the side of Lucky’s chest wall, and the smooth, rounded probe was pressed against his skin. A three-dimensional, moving picture could now be seen of his heart. Different parts of his heart could be viewed and measured, including the various valves and chambers.

The ultrasound examination revealed the precise cause of Lucky’s heart problem. One of the main valves of his heart had prematurely aged, causing thickening that prevented the valve from closing properly. As a result, there was a backflow of blood through the leaky valve, which was causing the murmur I could hear. This leaky valve meant that the heart could not function as efficiently as normal. The result was that fluid was gathering in Lucky’s lungs, causing his irritating cough.

Now that a full diagnosis had been made, treatment could be given. Ideally, a new heart valve would be the answer, and of course, this is common in humans, but not possible for dogs. Instead, Lucky was prescribed with two different types of tablets that work together to remove excessive fluid from his lungs, and to make it easier for his heart to pump blood around his body.

Lucky responded well to the medication and the cough settled down.


  • There are many different causes of a cough.
  • If heart disease is suspected, extra tests are important to confirm the diagnosis.
  • Modern treatments for heart disease can be very effective

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