One disease in particular, myxomatous mitral valve disease (MMVD) is said to account for 75% of heart disease and affects 85% of small dogs over 13 years old. Not all of these will need treatment, but many will. Later I’ll show you how to tell.

There is no question that recent advances have made MMVD much less of a death sentence than it once was. So it’s good to get to know pimobendan, the newest, and most commonly used of these treatments.

How Pimobendan Works

Pimobendan is a drug that unusually has two separate positive effects. First, it increases the strength of contraction of the heart, increasing the amount of blood delivered. Second, it dilates blood vessels in the general circulation, reducing the heart’s workload.

Pimobendan needs to be given at a dose of 0.2–0.3 mg/kg twice a day on an empty stomach, leading to the following inescapable logic. If it needs to be given one hour before any food and 12 hours apart, then even starting with a 7am dose will result in an 8pm dinner time. Now of course, we don’t recommend feeding dogs after dark…

You can picture the disappointment in peoples’ faces when they think this through. It’s definitely a drug for the early risers in the house. The only other alternative is to make their main meal in the morning.

Lifespan Of Dogs On Pimobendan

Early work demonstrated that pimobendan could help dogs with MMVD, but by how much was uncertain, and so vets like me were slow to change treatments that were already working. Then two large international studies appeared. With them came a sea-change in how we viewed this drug.

Each of them has something important to say about both effects and side effects. Both are referenced below.

2008: The QUEST Study

252 dogs with naturally occurring MMVD and congestive heart failure were divided into two groups: one taking pimobendan and another taking benazepril, the leading heart treatment at the time. Both were allowed other treatments as needed. They were then studied over the following years until one of the following three things happened:

1. sudden death
2. euthanasia for cardiac reasons
3. treatment failure

For pimobendan, the median time to this endpoint was 188 days. For benazepril it was 140. So a good result, but far from impressive. However, it’s worth pointing out here that these survival times are artificially short; many dogs in the study had already been affected for some time before beginning.

Real life is better. The point is more that in matched groups, pimobendan outperformed its rival.

2016: The EPIC Study

To my knowledge, the EPIC study was the first in veterinary medicine to be stopped early because of what was found. 354 dogs were chosen who had MMVD but were not yet in heart failure. At this earlier stage they had enlarged hearts as determined by xray and ultrasound.

Up to the time of the study, treatment was not believed to help at this stage, and so they were divided into dogs given pimobendan and dogs given a harmless placebo instead. This time the endpoint was chosen to be one of:

1. development of left-sided heart failure
2. euthanasia for a cardiac reason
3. death presumed to be cardiac in origin

The median time to this endpoint was 1228 days in the pimobendan group and 766 days in the placebo group. In other words, dogs with enlarged hearts but without heart failure had an extra 60% or 462 days of disease-free life if they took pimobendan.

This of course was a stunning result. Once it became obvious, all of the dogs were put on pimobendan.

Pimobendan Side Effects

Similar rates of adverse effects were reported for pimobendan and benazepril. This suggests that the drug is at least as safe as other heart treatments,

Pimobendan also recorded similar side effects to the placebo. Deaths in the pimobendan group were 46.4% versus 57.2% in the placebo group. This suggests that pimobendan is safe compared with any drug.

If you want to take a closer look, I’ve included the reported side effects from both studies in two tables after the references.

Help! Pimobendan Killed My Dog!

What then do we make of online reports of terrible events after dogs took pimobendan? The high rates of death and side effects in the placebo group provide the best clue. These are old dogs with a high risk of illness from any cause.

We humans are notoriously bad at separating causation from correlation. In fact, with any one dog, it’s virtually impossible to decide if a sudden death is caused by a drug or not. It’s only by looking at large groups that we can see the trend. Sometimes it’s real, other times it’s not.

Pimobendan may in fact cause deaths in some dogs. Even if so, the evidence tells us that they are heavily outweighed by the dogs that survive for longer.

When Should My Dog Take Pimobendan?

Pimobendan is a much better drug at stopping dogs going into heart failure than it is in treating them once they do. So here’s a quick summary of how to use pimobendan in 2022 and beyond:

1. Get regular checkups (at least annually) to look for early signs of heart disease. This is mainly the appearance of a heart murmur.
2. Once a murmur appears, watch fitness, coughing and resting respiratory rate closely and get a checkup at least every 6 months.
3. Follow your vet’s advice on further testing. Sooner rather than later they will want to do chest xrays and possibly cardiac ultrasound to look for the signs of heart enlargement.
4. Even if things are normal, expect things to change and so repeat the tests every 6 to 12 months based on your vet’s advice. Eventually you’re likely to spot the right time to start pimobendan.
5. Once started, most heart disease will stabilise but dose adjustments and extra medications will still be necessary as the disease slowly worsens (hopefully over years, not months). Therefore, keep attending scheduled checkups and get advice straight away if anything changes.

Most importantly, trust the science. It’s very hard to judge the efficacy of any treatment used to prevent a disease instead of treat it, but we actually have a lot to go on here.

Related: A Dog With Dilated Cardiomyopathy (also treated with pimobendan) caused by a grain-free diet

Update: Mitral Valve Repair

I hesitate to add this as I fear giving dog owners false hope, but several comments below have spurred me to also discuss the surgical option. As of 2023, there are now several centres around the world that offer open heart surgery to improve mitral valve function. It is not replacement of the valve, but instead modifying its shape or adding support so that the leak is less significant.

Costs are extreme (I would guess $40-50K) and availability currently limited to the UK, France, Japan and the USA. If you Google ‘dog mitral valve repair’ you should find useful information from these sites. There is no doubt that this procedure will become more commonplace with time, and hopefully more realistic.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

References

Boswood, A., Häggström, J., Gordon, S. G., Wess, G., Stepien, R. L., Oyama, M. A., … & Watson, P. (2016). Effect of pimobendan in dogs with preclinical myxomatous mitral valve disease and cardiomegaly: the EPIC study—a randomized clinical trial. Journal of Veterinary Internal Medicine 30,(6), 1765-1779. Full Article.

Häggström, J., Boswood, A., O’grady, M., Jöns, O., Smith, S., Swift, S., … & DiFruscia, R. (2008). Effect of pimobendan or benazepril hydrochloride on survival times in dogs with congestive heart failure caused by naturally occurring myxomatous mitral valve disease: the QUEST study. Journal of Veterinary Internal Medicine, 22(5), 1124-1135. Full Article.

Keene, B. W., Atkins, C. E., Bonagura, J. D., Fox, P. R., Häggström, J., Fuentes, V. L., … & Uechi, M. (2019). ACVIM consensus guidelines for the diagnosis and treatment of myxomatous mitral valve disease in dogs. Journal of veterinary internal medicine, 33(3), 1127-1140. Full Article.

The food that nearly killed her is a leading brand of grain-free dog food you can buy at nearly any Australian supermarket. I wish I could tell you its name.

Here’s what happened.

Rowdie’s Collapse

That’s Rowdie in the picture. She’s a 12-year old Beagle who’s always been in good health, including at a checkup early this year.

On the 16th of May, she was having a bath when she suddenly collapsed, rolled on her side and remained stiff and unresponsive for 10 to 15 seconds. She was taken to an emergency vet and had blood taken. The cause was thought to be a seizure.

I saw Rowdie a few days later. The first thing I thought was that it probably wasn’t a seizure: these go on for at least 30 seconds and have lots of muscular activity. Her history contained a further clue: she’d recently developed a moist cough.

Heart Disease, Not Seizure

More clues came from her examination. Her heart rate and her breathing were faster than expected, and I could feel fluid in her abdomen. Most importantly, she had a grade 3 heart murmur that wasn’t there just four months earlier.

The final clue was the bath. Seizures happen at any time, even during sleep. Rowdie’s collapse on the other hand happened at a time of increased activity.

I strongly suspected a heart problem and so we took chest xrays straight away. These showed an enlarged heart with pulmonary oedema (fluid on the lungs). Heart disease was confirmed.

Why Rowdie Though?

You see, Rowdie’s problem wasn’t typical. She’s not of a breed prone to heart problems, and she’d been normal so recently. Most cases of heart failure don’t come on without warning because we’ve been listening to the murmur getting louder for months or years beforehand.

Here’s where Rowdie’s luck turned the first time. Here in Adelaide we’ve always had a shortage of vets skilled enough to offer cardiac ultrasound, called echocardiography. Well just the week earlier I’d received news that a board-certified ultrasonographer was setting up a freelance service.

We started Rowdie on heart medications and booked her in for the soonest available appointment.

Echocardiography Saves The Day

The ultrasound exam saved her life. That’s because the results showed she had a very unusual form of heart disease that I never would have predicted: dilated cardiomyopathy or DCM.

DCM is when the heart muscle gets thin and weak, and it normally has a very short survival time. However, not in Rowdie’s case. It was while I was talking over the results with her owner that she got her second lucky break.

I remembered those reports about grain free foods. And so I asked about Rowdie’s diet.

Grain Free Diets & Heart Disease

It turned out that earlier in the year, Rowdie’s owners had started buying a grain-free dog food. Like most people, they assumed that if it was being proudly marketed as grain free, it must be better.

Vets have known for some time that this is not true, but we can’t get the message out to dog owners. The reality is that grain free diets are being regularly linked to dogs like Rowdie.

You can read more here. We don’t know exactly why, but theories include B vitamin deficiency, inhibition of taurine or carnitine metabolism, or unidentified, potentially cardiotoxic compounds. 89% of DCM-associated diets reported to the FDA contained peas¹.

Treatment of Diet-Related DCM

I advised Rowdie’s owners to put her back onto a quality grain-based diet, and added a taurine supplement as a precaution. She also needed to stay on the heart medications. There was no way of knowing if my suspicions were correct except by trying.

Even when DCM is caused by the diet, not all affected dogs can recover. It depends how much damage is already done, and her case was severe.

I saw Rowdie two weeks later. She was doing very well, which was probably just the effect of the heart meds. A month later she was doing even better, which by now was not what we expected for regular cases of DCM.

By the way, the best way to tell is by measuring sleeping or resting respiratory rate.

A Stunning Response

On the 11th of August we repeated the echocardiogram. Here is a summary of what was found:

• The dilation of the left ventricle had vastly improved, but was not completely resolved
• The left atrial enlargement had completely resolved
• The measurements of heart contraction (fractional shortening and EPSS) were now normal
• The regurgitation jet at the mitral valves was no longer visible

And here are the numbers:

The improvement was so great that it was debatable whether Rowdie needed to stay on heart medications any more. We’ve got one more ultrasound exam planned and then we’ll probably stop them.

A Warning To Dog Owners

What is critical for you, the reader, to understand here is how rarely dogs receive a cardiac ultrasound. Heart disease is one of the most common problems of dogs, but we lack the skilled sonographers to do all but a tiny fraction. I only ordered this test because there was something not quite right about Rowdie.

As nearly every case of canine heart disease has just one cause, it’s reasonable for vets to make assumptions. Especially in a user-pays system where any further investigation will add costs and delays. However, for Rowdie this would have been deadly.

There is no doubt in my mind that most cases of DCM caused by grain free diets will go undiagnosed. This would have happened to Rowdie too if she was a more ‘typical’ breed or had a more typical history. Which matters because this specific form often responds well to treatment especially if recognised early.

Without a realisation that the diet was to blame, Rowdie would have died quickly. Like the more regular cases of DCM, she would have responded briefly to the medications, but then started declining again.

These days I ask a lot more about the diet every time I hear a heart murmur. And I hope that the lesson for you is to avoid these diets until we can report which ones are faulty, and either fix or remove them.

Related: Why I can’t warn you about bad dog foods (yet)

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

Reference

1. Smith, C. E., Parnell, L. D., Lai, C. Q., Rush, J. E., & Freeman, L. M. (2021). Investigation of diets associated with dilated cardiomyopathy in dogs using foodomics analysis. Scientific Reports, 11(1), 1-12 Full text

Here I’m going to give you a very simple trick to recognise when a cat is struggling to breathe. If you do it successfully, your cat will probably be OK.

How To Tell If A Cat Has Breathing Problems

Unlike dogs who are regularly exercised, cats can hide respiratory distress for a long time. But there’s one thing they can’t hide: the fact that they are breathing faster and faster.

A sleeping or a resting respiratory rate greater than 30 breaths per minute is almost always abnormal. This is usually the earliest and most sensitive sign of breathing problems. The problem is that it isn’t natural for cat owners to notice.

This is often the only sign. However, sometimes you might also see:

• open-mouth breathing
• noisy, raspy or wheezy breathing
• frequent coughing or hacking
• obvious chest or stomach heaving
• upright, tense posture

Cats with breathing trouble usually can’t breathe when lying down. The picture above shows the typical posture of such a cat: hunched and upright, not relaxed.

In contrast, even young healthy cats can have rapid or heaving respiration, or even breathe with their mouth open. However, this should only happen for a few minutes after vigorous exercise, and never at rest.

How To Measure Resting Respiratory Rate

The trick is to understand that the rate of breathing changes with activity or stress. Therefore, it can’t be done just any time and you need to know what to look for.

Resting Respiratory Rate should be measured when your cat is at their most relaxed. They need to be unstimulated and preferably even asleep. This is when they are breathing at the slowest they can, and this is what you measure.

Now count the number of breaths over 60 seconds. Most cats have a normal value between 15 and 25, but this can be higher in hot conditions.

If you can’t see your cat breathing at all (but they are alive!) then the rate should be OK. Cats with respiratory issues usually have more laboured or heavy breathing which is easier to see.

What Causes Laboured Breathing?

These are the most common three reasons for a cat to be consistently breathing faster than 30 breaths per minute:

• heart disease
• chest infections
• asthma

They all need urgent attention, but they all can be treated.

I’m not expecting cat owners to watch their cats breathing every day, but whenever you suspect a problem it’s a great thing to do. For certain cases (like cats with heart murmurs), it’s something I ask owners to do as an early warning.

By spotting a subtle increase in your cat’s respiratory rate, you’ll take what would have been a dire emergency and make it just another health problem.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here. The information provided here is not intended to be used as a substitute for going to the vet. If your pet is unwell, please seek veterinary attention.

When a dog suddenly falls over or cannot use their back legs, it is usually an emergency. You should travel to a vet.

On the way, take a video if you can. Here are some things to look for:

1. Is there muscle movement? This is common in seizures or poisonings.
2. Is the dog unconscious? Look for a lack of response and passing urine or faeces.
3. Are the eyes moving? Vestibular disease causes nystagmus or eye flicking.
4. Is the heart rhythm normal? Place your hand on the chest and try to feel it.
5. How long does it last? Fainting and airway issues usually only last for seconds.
6. Is recovery quick? After seizures, dogs commonly appear incoordinated for some time.
7. What was the dog doing beforehand? Cardiac, respiratory and thermal problems are more common after exercise.

Cardiac arrest is an extremely uncommon cause, and therefore it is not recommended to try CPR. You will see that most causes either recover by themselves or require treatment that only a vet can give.

Now let’s dive deeper into each of these causes…

Cardiac Causes Of Collapse

Collapse would make people immediately think of the heart, and they’d mostly be right. Any heart disease can cause collapse due to fainting or syncope, which is essentially ‘blacking out’ from a lack of oxygen in the brain.

Cardiac collapse most often occurs after excitement or exercise, and might only last a few seconds each time. In our clinic, the following heart diseases are more likely to cause collapse:

• rhythm disturbances (arrhythmias such as heart block, Boxer cardiomyopathy)
• late stage mitral insufficiency
• pericardial effusion

Many causes are treatable. Read more about these in our page on heart diseases.

Shock & Bleeding

The most common cause of acute shock is bee sting in dogs.

Low blood volume or anaemia can cause collapse that looks just like cardiac disease. The best clue is very pale, almost white gums. Perhaps the one we see most is rat bait poisoning, which causes internal bleeding. Two autoimmune diseases which have similar signs are platelet deficiency and haemolytic anaemia.

Another common cause of sudden collapse due to internal bleeding is a tumour of the spleen called haemangioma or haemangiosarcoma. It is seen mostly in older large breed dogs. Spleen removal can be curative but an ultrasound exam is best done first to look for tumour spread.

Rapid fluid shifts in the body cause shock, of which by far the most common cause is any severe and sudden gastroenteritis. In these, body fluids go from the blood vessels into the gut faster than they can be replaced and the circulation collapses. The treatment is of course prompt restoration of the fluids via a drip.

Respiratory Causes Of Collapse

Any problems of the airways or lungs can cause collapse due to hypoxia. Here are some of the ones we see more often.

Brachycephalic Obstructive Airway Syndrome or BOAS occurs in dogs with short faces, like Bulldogs and Pugs. When there’s a need to breathe quickly, the soft palate that lies over the larynx in some dogs will block enough airflow to cause collapse. This can be complicated by a narrow trachea (windpipe) and small nasal openings.

If a brachycephalic breed has noisy breathing even when at rest, or gets tired easily, they almost always benefit from airway surgery. Acting proactively can save a life.

Collapsing trachea is a common cause of a honking or harsh dry cough in older small breeds. When they get hot or excited, the airflow through the flattened windpipe sometimes can’t keep up with demand and the dog might collapse for a few seconds. Treatment involves various medication combinations, weight loss, avoiding excitement, and surgery as a last resort.

Laryngeal paralysis is a similar problem mainly seen from middle age in medium and large breeds. Instead of a cough, they have harsh, raspy breathing that gets louder with exercise or temperature. Collapse most commonly occurs in warm conditions, but can be prevented by timely surgery.

Pulmonary hypertension is a rarer disease of the lungs secondary to many problems, such as heartworm, birth defects in the heart and a specific disease of West Highland White terriers. It can also happen when blood clots are formed associated with immune-mediated haemolytic anaemia, protein-losing diseases and Cushing’s disease.

Neurological Causes Of Collapse

Any poison that affects the nervous system can cause a dog to collapse. In Australia, the most common are:

• any recreational drugs
• chocolate
• macadamias
• 1080 and strychnine
• xylitol
• some mushrooms

Three neurotoxins found in Australian animals also deserve special mention: tick paralysis, cane toads, and snake bite, which often causes immediate collapse followed by a short-lived recovery. Other toxins are ethyl glycol in engine coolant, bromethalin in rat baits outside Australia, insecticides and herbicides.

What about deliberate dog baiting? It’s rare, but does happen. Read more at the link.

Any injury or trauma to the brain or spinal cord can cause collapse. The best example of this is intervertebral disc disease, which is especially common in dogs like Dachshunds.

Seizures can also be a cause of collapse. Usually they’re easy to identify by paddling leg movements, jaw champing and salivation, but sometimes these aren’t obvious. That’s especially true for partial seizures where the dog remains conscious throughout.

A portosystemic shunt is an abnormal blood vessel that sends unprocessed blood from the gut directly to the brain, bypassing the liver. It can cause collapse especially not long after a meal. A shunt would be high on the list in a young adult of a susceptible breed such as the Maltese.

Low blood sugar also causes neurological signs. Collapse in a diabetic dog is most often due to a high insulin dose suppressing blood glucose levels, but we also see it with insulinoma, Addison’s disease and very young puppies not getting adequate nutrition.

The last item on the nervous system list is vestibular disease. This refers to any disorder that affects the balance organs in the inner ear and brain. These dogs have a head tilt, fast flicking in the eyes, and usually can’t stand up. The most common is Idiopathic Vestibular Syndrome, but you can read all the common causes of vestibular disease here.

Musculoskeletal Causes

As a young vet, I didn’t believe it when I first saw simple arthritis cause a dog to collapse. Why would a long-term disease known for slow worsening lead to sudden collapse? Now I understand that these dogs have been putting up with pain until they couldn’t any longer.

We see this mainly in larger breeds, and especially German Shepherds. Often they will be howling or crying and brought in on a stretcher. Good intravenous drugs (especially cortisone) can do wonders to get them up again but they really need long-term pain control to keep them going.

Of course, we should view these dogs as our own failure. To do it right would be to identify and treat their pain before it gets too much.

Exercise-Induced Collapse

Let’s finish up with two unusual conditions. Hyperthermia or heat stroke won’t often cause outright collapse, but it can cause an unsteady gait and vacant expression. The clue is that it should happen after prolonged exercise or excitement especially in warm weather.

We see heat stroke most in dogs obsessed by ball-chasing, or overly excitable dogs, but there may also be a genetic influence in some breeds such as Spaniels. For many dogs, the solution is to realise that dogs don’t know when to stop and that you need to regulate their exercise and keep them calm.

Exercise induced collapse is a genetic fault found in Labradors, Border Collies and others. It causes muscle weakness, incoordination and life-threatening collapse after intense exercise. The genetic mutation in Labradors is now understood and screening by many breeders should reduce the incidence.

This list is by no means complete but all the common reasons for collapse should be found here. Diagnosis will require your vet using the history you give them, taking a physical exam and choosing the right tests to confirm their suspicion. Good luck.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here. The information provided here is not intended to be used as a substitute for going to the vet. If your pet is unwell, please seek veterinary attention.

These cats are in severe distress from having cold, hard, painful hind legs and pulmonary oedema. They also often have pre-existing heart disease.

The first cat I saw, I treated as I’d been taught and he made a rapid and full recovery. As far as I know he went on to live a good life.

The problem is that this experience was an outlier, only I didn’t know it. It meant that for many years afterwards I’d see other cats with ATE give their owners a positive outlook and attempt to treat them.

I say ‘attempt’, because they always did badly, even though I used the same treatment. There’s almost nothing worse for a vet than trying to treat a suffering patient only to realise three days later you should never have put them through it. We want to avoid that at all costs.

My mistake was prioritising my personal experience over the science. Here’s what it says:

Treatment of Aortic Thromboembolism In Cats

Four large studies look at success rates for the treatment of cats with ATE

• 33% survival with a medial survival time of 51 days (46 cats)
• 37% survival with a medial survival time of 11 months (100 cats)
• 39% survival with a median survival time of 6 months (44 cats)
• 31% survival with a medial survival time of 4 months (127 cats)

In looking at these results, we have to keep in mind two things. Firstly, these cats were treated in 24 hour intensive care referral centres, not private clinics. Secondly, how important it is to look at long-term survival data, not just how many get out of hospital.

Now you know that these terrible rates of success exist despite the best of care, you will hopefully see why I now only offer two options to cat owners facing ATE:

1. Emergency referral to a specialist centre, with a clear warning of the poor prognosis
2. Humane euthanasia

In my opinion, given the suffering, anything else is inhumane. This is just my view, and if your vet feels differently, I cannot argue. It’s a judgement call.

Though I suspect I am not alone, judging by a recent paper. Of 250 cats with ATE seen in general practice, the decision between vets and owners was euthanasia for 153 of these. When you look at the rest you can see why: only 30 of the remaining cats were still alive one week later, and their median survival time was only 3 months.

But if you’re reading this because your cat’s unwell, don’t give up yet. ATE is not the only cause of a cat’s back legs suddenly not working, or dragging the back legs. Get to your vet ASAP and get a proper diagnosis before making any decision.

So what about the positive information you read on online forums?

The Outlier Effect

When you search online about your dog’s or cat’s illness, you’ll quickly find forums, full of well-meaning advice. Some of it is undoubtedly useful; after all, these are real experiences from pet owners sharing what you’re going through.

However, some is extremely misleading. The outlier doesn’t know they’re an outlier, and even I was guilty of that despite knowing better. Outliers are also more likely to be the ones wanting to share their experiences, whether good or bad.

I use forums too. I find them especially useful when I want to know if something has ever happened, or if anyone has reported the thing I’m seeing. What I’ll never do without checking is use any advice I see, whether on treatment or prognosis. For this we need science.

Blimey, I won’t even use case reports, which are published accounts of a single case. I need to see good outcome data, enough to make an informed decision. I certainly don’t need unrealistic expectations at this most critical time.

In the case of diseases like aortic thromboembolism, using anything except good science is likely to lead to false hope and bad decisions like mine. I’ve learnt my lesson, but if it was so hard for me I can understand why it’s even harder for cat owners.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

Further Reading

Borgeat, K., Wright, J., Garrod, O., Payne, J. R., & Fuentes, V. L. (2014). Arterial thromboembolism in 250 cats in general practice: 2004–2012. Journal of veterinary internal medicine, 28(1), 102-108

Moore, K. E., Morris, N., Dhupa, N., Murtaugh, R. J., & Rush, J. E. (2000). Retrospective study of streptokinase administration in 46 cats with arterial thromboembolism. Journal of Veterinary Emergency and Critical Care, 10(4), 245-257

Laste, N. J., Harpster, N. K., Harkins, J. D., Stanley, S., Mundy, G. D., Sams, R. A., … & McAllister, P. M. (1995). 2392581. A retrospective study of 100 cases of feline distal aortic thromboembolism: 1977-1993. Journal of the American Animal Hospital Association, 31(6), 492-500

Schoeman, J. P. (1999). Feline distal aortic thromboembolism: a review of 44 cases (1990–1998). Journal of Feline Medicine & Surgery, 1(4), 221-231

Smith, S. A., Tobias, A. H., Jacob, K. A., Fine, D. M., & Grumbles, P. L. (2003). Arterial thromboembolism in cats: acute crisis in 127 cases (1992–2001) and long‐term management with low‐dose aspirin in 24 cases. Journal of veterinary internal medicine, 17(1), 73-83

When Is A Swollen Belly An Emergency?

Dogs with any of these symptoms need to be taken to a vet immediately:

• Vomiting
• Hard, painful abdomen
• Collapse
• Severe lethargy
• Not eating

Now dive deeper…

The picture above shows what a dog’s normal body shape should be.

Could it just be fat? The answer is usually ‘no’. Overweight dogs are so common that they look normal to most people. Therefore, trust your instincts: if the stomach looks odd, it’s almost certainly not just fat.

For example, the pictured dog isn’t fat anywhere else, and the belly hangs down more than it should. Even though he seems well, he’s in a lot of trouble.

Causes Of An Enlarged Abdomen

There are many reasons why the stomach gets bigger than normal. I’ll classify them by the cause of enlargement and start with the most serious. There are two special cases in puppies near the end.

Gas: Bloat

Bloat or GDV occurs when the stomach suddenly twists and blocks the escape of gases. Gastric expansion follows, and without treatment dogs die a rapid and horrific death.

Affected dogs are usually large breeds with obvious distress and a hard, painful abdomen. If your dog is comfortable and eating or drinking, they don’t have bloat. You can read more about the causes and prevention of bloat here.

Sometimes a dog’s stomach swells up with gas for less serious reasons, like overeating. I saw one this week which happened with no obvious cause. These dogs need xrays to tell them apart from life-threatening cases of bloat, and to monitor the stomach size.

Pain: Peritonitis

Abdominal pain makes dogs hold their belly stiff and tight like a drum. We call this splinting. You should always treat this sign as an emergency.

The most common cause is pancreatitis, which you can read about at the link. However, this is indistinguishable without testing from other causes of inflammation or infection, such as:

• Intestinal obstruction from swallowing the wrong thing
• Ruptured or twisted bowel
• Gall bladder diseases
• Gunshot or stake injuries

Blood: Haemorrhage

Internal bleeding can cause the belly to look bigger, however it’s rarely the most obvious sign. These dogs are also usually weak, pale, lethargic or even collapsed.

There are two common causes of abdominal bleeding:

1. Eating rat poison stops the blood from clotting, and although there’s an antidote, most dog owners haven’t realised their dogs ate it until symptoms begin
2. Haemangiosarcoma is a tumour of the spleen whose first sign is often unexplained blood loss

It’s also very possible to have abdominal haemorrhage after any major surgery or injury. Obviously, whatever the reason, bleeding is always a critical emergency.

Urinary Tract Damage

Damage anywhere in the urinary tract can cause urine to leak into the abdomen. The most common reasons for this are bladder stones blocking the urethra, and car accidents.

Like with bleeding, the amount of fluid is mostly small, and other more obvious signs of illness are present, like lethargy, straining or pain.

Food: Overeating

A classic and sometimes serious cause of bloated stomachs is when a dog biscuit bag is left out while you’re not at home. Most dogs will binge on the kibble until they can’t eat any more, then the kibble starts to swell as it takes on water. These dogs often need the vet to induce vomiting to relieve the distress.

In puppies, abdominal distension after eating is quite normal. As long as they are bright and playful, and it goes down in a few hours, there’s nothing to worry about. However, the next cause also needs consideration…

Parasites: Worms

Intestinal worms are a very common and serious reason for a swollen stomach in a young puppy. Roundworms (pictured) often get large and numerous enough to swell the belly and block the passage of food.

Read all about preventing and treating intestinal worms here.

Fluid: Ascites

Many diseases cause the buildup of a clear fluid that we call a transudate. Most of these slowly worsen without any other major signs of illness. Examples might be:

1. Heart disease
2. Caval syndrome from heartworm
3. Portal vein obstruction from tumours
4. End stage liver disease
5. Certain widespread cancers
6. Protein-losing enteropathy
7. Protein-losing nephropathy

The first four happen because the blood pressure in abdominal vessels gets high enough that fluid leakage occurs. Number 5 is simply because fluid often escapes from tumours with a high surface area.

Numbers 6 and 7 are probably the most common. They happen when blood proteins are being lost through the gut or via kidney disease. This leads to a drop in plasma oncotic pressure, which causes fluid to leak from small vessels. The fluid will also often be present in the chest cavity.

Testing is essential to identify and treat the cause. Often all of the following are needed:

• History & physical exam
• Ballottment of the abdomen (percussing one side of the belly and feeling for a fluid wave on the other)
• Blood and urine tests
• Ultrasound exam
• Intestinal biopsy

The most common cause is inflammatory bowel disease as a consequence of protein-losing enteropathy. You can read about that here. As you can imagine, without treating the cause, drainage of the fluid is usually useless.

Fat: Hormonal Diseases

Even though fat deposition is unlikely, there are two diseases in which it is laid down in a way that can look like a swollen stomach. These are:

• Cushings disease, associated with an enlarged liver, pot belly, hair loss and excessive drinking
• Thyroid disease, associated with lethargy and unexplained weight gain 

You can read about tests and treatment for both diseases at the links.

Masses & Enlarged Organs

Sometimes a tumour in the abdomen can get so large that it causes the belly to noticeably bulge. These are usually slow-growing benign masses, otherwise they would have caused other signs earlier. Swelling can also occur when organs themselves become enlarged. Perhaps the most important are the liver and spleen. 

Diagnosis requires blood testing and an ultrasound exam. Even large masses can often be removed if there is no evidence of spread.

Uterus: Pregnancy & Pyometra

Lastly and very rarely I have seen owners of a female dog not be aware of a mating 5 to 6 weeks earlier. In older un-desexed females, a uterine infection called pyometra or reproductive tract cancer can also swell the abdomen in a similar way. 

These unplanned events should be a lot less common now that desexing has become compulsory in Adelaide.

I’ll end on a positive note. Despite some of the horrendous diseases mentioned here, most causes of abdominal enlargement that I see are the ones that can be treated, often with just a tablet. Therefore, don’t be frightened of getting the vet to take a look. It’s usually all for the better.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here. The information provided here is not intended to be used as a substitute for going to the vet. If your pet is unwell, please seek veterinary attention.

[There is] compelling evidence that a nutritionally based, partially reversible cardiomyopathy occurs in some dogs fed non-major brand grain free diets.

Journal of Veterinary Cardiology 2019

Enough evidence now exists to warn dog owners. Some diets they choose appear to cause a heart disease called dilated cardiomyopathy. These dogs can often be saved with a simple diet change if the cause is recognised early enough.

A Brief History Up To Now

Dilated cardiomyopathy or DCM is a nasty disease where the heart muscle gets weak and thin. We’ve known for a long time that it’s common in Dobermans but we also see it in many giant breeds of dog. The cause has always been assumed to be a genetic fault.

In the 1990s we got the first hints that diets were also a factor. Cardiologists started noticing unexpected breeds like Cocker Spaniels and Golden Retrievers getting DCM, this time related to a taurine deficiency. It wasn’t long before they also noticed that a lot of them were eating the same, unusual foods.

The diets involved were a few boutique brands, all containing lamb or rice. The assumption was made that certain breeds were more sensitive to a faulty diet. Whatever the cause, it seems like those diets were fixed, because for a while things went quiet…

Then in 2018 an unusual spike of DCM cases was noticed. This time, it seems that a wider list of dog breeds are involved and they all have one thing in common: diet. And it isn’t as simple as a taurine deficiency any more.

The Diets Linked With DCM

It’s not just grain-free diets.

Have you noticed how many new brands have appeared on the market in the past ten years? They may contain an unusual ingredient, have a ‘special’ or ’boutique’ feel, or tout the benefit of avoiding grains. These are the sort of diets that the affected dogs are eating.

The term the cardiologists and nutritionists use is boutique, exotic-ingredient, or grain-free (BEG). By this they mean diets which may have one or more of the following features:

• Manufacturing by a smaller company
• Not undergoing feeding trials before sale
• Using potato or pulses (peas, beans, lentils etc) instead of grains

You can read the FDA’s full report here which names the foods most commonly linked with DCM. However, these are only those in the USA.

Suspicion has also fallen on vegan and vegetarian diets. Of course, many BEG diets will be just fine but there’s now a clear link with some of them and DCM. We can expect this problem to exist wherever these foods are sold, including Australia.

And in fact, here is an article from 2021 featuring one of our own patients here in Adelaide.

Is It A Taurine Deficiency?

A long time ago vets realised that taurine is an essential amino acid of cats, and that without it they develop DCM. However, the current situation in dogs is not that simple. Most of the diets from sick dogs have adequate levels of taurine when analysed, and the dogs usually have adequate plasma levels too. Let’s also not forget that, unlike cats, dogs can manufacture their own taurine.

However, it is still true that if we give these dogs taurine supplements, even without changing the diet, many get better. That makes nutritionists suspicious that something in these diets is interfering with taurine metabolism.

It’s also possible that there is an as-yet unrecognised cardiac toxin or deficiency unrelated to taurine. Diets aren’t just a list of ingredients; once you combine them, unexpected things can happen. Just look at how hard it’s been to work out why so many Australian dogs died of megaoesophagus even though we know the food that did it.

What Dog Owners Should Do

Firstly, don’t panic. The vast majority of dogs on BEG diets will remain perfectly healthy. However, personally I would be moving to a larger manufacturer that conducts feeding trials.

Of course, one of these (Hills) had its own health scare recently so nobody’s perfect. You can read about the Hills recall here and here why I still feed Hills foods to my pets.

What I would not recommend is a wholesale move to home-made diets. I’ve published what I believe to be a balanced home made diet, but I still believe that these are not a good idea for the majority of dog owners. How many will invest in the vitamin and mineral supplements needed for balance, and how many have the storage space and time? Some, yes, but not all.

And then there’s the fact that we still have the issue of using an untested diet.

For owners of dogs with DCM, there are two big messages.

First, dogs with DCM on non-traditional diets have a much better prognosis if you are willing to change their food to a more traditional type. They can experience improvements unavailable to dogs with ‘regular’ DCM.

Second, if your dog has DCM for any reason, ask your vet for a taurine supplement. We can’t test which dogs need taurine, so we should be giving it to all dogs with DCM. I’d even give it to Dobermans. We aren’t sure of the correct dose, but here are some guidelines:

Taurine should be safe and harmless when given to normal dogs. Then if your dog is lucky enough, the prognosis for this special type of DCM can be quite good. However, I fear that many dogs with DCM died without anyone asking what they were eating.

If you’re reading this, not any more. Pass it on!

Related: The Pros & Cons Of Grain-free Diets

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

Further Reading

Adin, D., DeFrancesco, T. C., Keene, B., Tou, S., Meurs, K., Atkins, C., … & Saker, K. (2019). Echocardiographic phenotype of canine dilated cardiomyopathy differs based on diet type. Journal of Veterinary Cardiology, 21, 1-9.

Freeman, L. M., Stern, J. A., Fries, R., Adin, D. B., & Rush, J. E. (2018). Diet-associated dilated cardiomyopathy in dogs: what do we know?. Journal of the American Veterinary Medical Association, 253(11), 1390-1394. Full text.

Freid, K. J., Freeman, L. M., Rush, J. E., Cunningham, S. M., Davis, M. S., Karlin, E. T., & Yang, V. K. (2020). Retrospective study of dilated cardiomyopathy in dogs. Journal of Veterinary Internal Medicine. Full text.

• A young, social dog with no other signs of illness is at low risk
• An older dog or any with lethargy or loss of appetite is higher risk
• Dogs with an elevated breathing rate should see a vet urgently

Now dive deeper…

Coughs in dogs are common enough that almost all of our dogs will have one at some time in their life. Some will be serious, others less so.

It’s also quite possible you will get the wrong advice. Our understanding of the causes of coughing has changed, especially for older dogs. It’s certainly not as simple as knowing whether it’s a wet or a dry cough. 

However, before we get to the causes, there’s one question we always need to ask ourselves…

Is It Even A Cough?

This might seem a strange thing to say, but trust me, it’s not. Most dogs that cough are also gagging and retching, making for a very confusing picture. Here are just three signs often mistaken for coughs:

• Reverse sneezing is a loud snorting or choking noise made in the back of the throat. If you’ve never seen it, I’ve put up a few videos here.
• Post-nasal drip occurs when thick mucous secretions from the nose or sinuses run over the back of the soft palate to the larynx. The clue is that these dogs are mostly snorting or sneezing. Find the causes of sneezing and nasal discharge here.
• Retching and vomiting often look like coughing in dogs. Perhaps the best way to tell is that vomiting dogs have usually also lost their appetite.

Odds-on your dog will miraculously stop coughing when they reach the vet. Therefore, the best way to put a smile on your vet’s face is to take a video with your smartphone. It won’t necessarily tell us what type of cough it is, but it should at least tell us which body system to investigate first.

So let’s say you’re confident what you see is a cough. Let’s look at why it might be happening.

Causes Of Coughing In Young Dogs

A simple way to get a rough idea of what might be wrong is the age of the dog. While (of course!) anyone can get anything, generally young and old dogs get different diseases. Add to that a good physical exam, possibly an X-ray and we’re usually in a good position to tell you what’s wrong. 

Causes of coughing in a young dog are mostly infections.

Kennel cough

Kennel cough or infectious laryngotracheitis is extremely common in social dogs (you can read a whole article on it here). Key points are:

• It’s acquired anywhere, but especially from dog parks
• It has an incubation period of around seven days
• Vaccination is good, but not perfect

Treatment of kennel cough is mostly via anti-inflammatories. By reducing the discomfort, the cough reflex gets a lot better and the poor doggies can sleep. We also use antibiotics and cough suppressants in selected cases.

Foreign material

Just like people, dogs can inhale solid objects into their airways. While anything can do it, we mostly see one of two scenarios:

1. Grass seeds can get stuck anywhere due to their spiky nature. We generally see them in the nasal passages but sometimes they get inhaled right into the lungs.
2. Food can be inhaled into the lungs, from where it causes aspiration pneumonia. Most of these dogs have something else wrong, like laryngeal paralysis or megaoesophagus but it’s also why we’re so careful about not giving anaesthetics unless the stomach is empty.

Aspiration pneumonia has a characteristic appearance on X-rays. Grass seeds are a lot harder to see and require us to be suspicious to go further. Therefore, it’s a good idea to let your vet know if there are a lot around at home.

Heartworm

Up to the late-1990s, heartworm was our most common cause of unexplained coughing. These dogs got very sick, and many died. With the advent of good heartworm prevention, this has become just a memory, but it’s still common in areas with poor levels of control. You can read more about our experiences with heartworm in Adelaide here. 

Bronchopneumonia

Infection of the lungs is a lot less common in dogs than people. That’s probably because dogs don’t get the human cold or flu, but also because gravity is on their side. It’s a lot easier to cough things up if your lungs are horizontal!

However, we do see occasional unexplained pneumonia. As long as we treat them promptly, these dogs should make a full recovery. 

Why Old Dogs Cough

Most of the reasons for an old dog coughing are the effect of ageing on the body. We’ll start with two common conditions that affect the cartilage.

Tracheal Collapse & Bronchomalacia

If you feel your windpipe it will no doubt be hard and inflexible. That’s just how it should be. Yet for unexplained reasons, the cartilage in many old dogs gets soft. Then, during the breathing cycle, the weakened cartilage is unable to maintain its normal shape.

If this happens in the windpipe, it often results in tracheal collapse. The usually round trachea becomes oval and can even collapse completely so that the sides touch. 

You can imagine how distressing and uncomfortable this is for the dog. Attempts to breathe only increase pressures and make the collapse worsen. Airway irritation stimulates a harsh cough that in turn adds further irritation. 

Excitement and neck pressure tend to make tracheal collapse worse. I really feel for these dogs. 

Bronchomalacia is the same process when it occurs in the smaller airways of the chest. The distinction is important as this cough is often confused with heart failure. 

Treatment for either problem is never easy. Surgery is rarely a realistic option, so we have to rely on juggling a combination of the following:

• Anti-inflammatories
• Weight loss
• Cough suppressants
• Bronchodilators

It’s almost never possible to stop the cough completely, but we can usually at least reduce distress and give comfort.

Cardiac disease

A heart problem can cause a cough in two ways. 

1. Pulmonary oedema causes fluid to accumulate in the lungs until it stimulates a cough reflex. We see this cough more commonly after lying down and especially at night. Often the dogs will also have an elevated respiratory rate (above 30 per minute) and cough up small amounts of white foam. 
2. Heart enlargement causes the airways above the heart to be compressed. This is especially likely if there is also bronchomalacia.

These days, most heart specialists think that ‘cardiac coughs’ are being over diagnosed. It’s vital that we don’t assume that just because a coughing dog has a heart murmur that the two are related. 

A dog with a heart problem, not just a murmur, will usually also have poor fitness and rapid breathing. At a bare minimum, we should at least do an X-ray to be more certain. Treatment is then via:

• Diuretics to reduce pulmonary oedema. 
• Drugs for heart disease to improve performance and reduce heart size. 
• Plus treatments for bronchomalacia (above) and bronchitis (below) if need be. 

Chronic bronchitis

Bronchitis is another disease that can affect the same animals. In fact, it’s not unusual for all three to have a role in an old dog’s cough.

Bronchitis responds best to either antibiotics, prednisolone or both. Despite the changes you might see on an X-ray, it often comes down to a ‘treatment trial’ to see what works.

Are you starting to get the idea that old coughing dogs are challenging?

Laryngeal paralysis

I’ve already mentioned laryngeal paralysis in the context of aspiration pneumonia but it’s really a disease of older dogs. These are usually larger breeds of dogs with characteristic raspy breathing that gets worse with exercise and warm temperatures. The treatment is surgical. 

Rare Causes Of Coughs

The last few I have almost never seen but are included for the sake of completeness. 

• Parasites are a rare cause of coughing in Australian dogs, but reasonably common in other parts of the world.*
• Eosinophilic pneumonitis is the closest thing we see to an allergy response. Strangely, we almost never see coughs from dust or smoke.
• Cancer in the chest can cause coughing but it mostly causes difficulty breathing.
• A dog that eats rat poison might cough from bleeding in the lungs.
• Some fungal infections are very common in certain places.
• Both the distemper and hepatitis viruses can cause coughing.

What To Give A Dog For A Cough

The use of cough suppressants without a diagnosis is never a good idea. In our desire to get rid of a cough it’s easy to forget that most coughs are doing something useful: clearing the lungs of material that shouldn’t be there.

Successful treatment is entirely about understanding the cause. The final thing to say about coughs is that it’s not really possible to tell them apart at home. Hopefully, I’ve given you an idea of what might be wrong, but you always need a vet to get a proper diagnosis. And it really matters to get it right, as I hope you can see.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here. The information provided here is not intended to be used as a substitute for going to the vet. If your pet is unwell, please seek veterinary attention.

*Four species of worm (Crenosoma, Oslerus, Capillaria, Angiostrongylus) can cause coughing in certain areas. 

If A Pet Has A Heart Murmur

1. Don’t panic! A heart murmur doesn’t mean much on its own.
2. Learn the signs of heart failure so you know what to look for.
3. Get your pet’s heart checked regularly

now dive deeper…

Max the Bengal cat has a heart murmur. He came in for something else and it was only during a routine physical that we found it. He’s not sick or showing any signs of heart problems. Should his owner worry?

Heart murmurs are common in dogs and cats. They can mean nothing but can also be essential to monitor.

What Is A Heart Murmur?

The audio clip above shows what to a vet would be a loud and obvious heart murmur. Instead of the normal lub-dub, lub-dub, the heart is going whoosh, whoosh. We call this type a systolic heart murmur, meaning it occurs only when the heart is contracting.

The whooshing noise is the sound of abnormal turbulence in blood flow. Normal hearts should produce a smooth laminar flow of blood so that the only noises you hear are the sounds of valves closing. “Lub” is the sound of the mitral and tricuspid valves, and “dub” is the aortic and pulmonary valves.

What Heart Murmurs Mean In Pets

The most likely reason why a pet has a heart murmur will be a heart defect. In puppies and kittens, there are also innocent murmurs. These are a murmur for which no cause can be found. The good news is that these can be up to half of the murmurs heard in young dogs and cats.

Below I have listed the common causes of murmurs for puppies, dogs, kittens, and cats. In addition to heart-related reasons, anaemia can also cause a murmur by making the blood too thin.

Do Dogs & Cats Grow Out Of Heart Murmurs?

Some puppies and kittens can grow out of heart murmurs by approximately 16 weeks of age. These murmurs are usually low grade and should show no signs of affecting the animal. Signs of a heart murmur being a problem are:

• Being quieter than their littermates
• More rapid respiration and heart rate
• Weak pulses and poor gum colour or refill

A vet can easily help you decide. Unfortunately, it’s more common for a murmur we hear in a young animal to be present for life. Even if mild, it is likely to be a congenital fault and so the animal should be desexed to prevent breeding.

Life Expectancy & Heart Murmurs

A dog or cat can live with a heart murmur for life. This is especially the case if a number of things are true:

• The murmur is only graded 1 or 2 (see the grading system below)
• The murmur does not progress or worsen
• There are no other signs of heart disease

In other words, you need a vet to keep an eye on it. While it’s always better to investigate a murmur, it’s acceptable to monitor it closely and investigate those of grades 3 and above in young dogs. In cats, it’s worth investigating all grades of heart murmur.

The prognosis for an older dog that develops a murmur depends on the speed at which it worsens. While it’s also OK to wait and see with mild murmurs, it’s best that you start getting more regular checkups.

Adult cats should start with blood testing to look for hyperthyroidism. Cats with heart diseases have more unpredictable lifespans than dogs. We see some cats that nearly die from severe failure able to live normal, symptom-free lives on treatment.

My Pet Has A Heart Murmur- What Do I Do?

Most heart murmurs in puppies and kittens are found by vets at the 6-week vaccination. This allows the breeders to make an informed decision and disclose the fault to potential purchasers. However, we still see a few that slip through, which is why we always advise a free checkup within days of arrival.

If your pet has a murmur, the best thing you can do is follow your vet’s instructions. Visit this page to read about the tests and treatment for heart disease that may be needed.

For cats, monitoring their resting respiratory rate provides useful early warning.

Grades Of Heart Murmurs

If your dog or cat has had a murmur diagnosed, you’ll want to know how bad it is and if it’s changing. In general, the higher the grade, the more likely a murmur is a concern*. Here’s how murmurs are graded :

1. Heard only after several minutes in a quiet room with a quiet animal
2. Easily heard but quieter than the heart sounds
3. The same intensity as the heart sounds
4. Louder than heart sounds but no ‘thrill’
5. Loud with a thrill (vibration) now able to be felt
6. Very loud with thrill and wide extent on the chest

*(except VSD)

Causes of Murmurs in Puppies

In order, the four most common causes of heart murmurs in shelter puppies are:

1. Pulmonic Stenosis (PS): narrowing of the outlet from the right ventricle.
2. Patent Ductus Arteriosus (PDA): failure of closure of a shunt at birth.
3. Aortic Stenosis: narrowing of the outlet from the left ventricle.
4. Ventricular Septal Defect: a ‘hole’ between the two chambers. Unlike the others, usually, the noisier these are, the smaller the hole.

About 1 in 400 shelter puppies have a murmur, though I would expect the rate to be higher for purebreds. The cause can only be properly diagnosed by cardiac ultrasound, although we often suspect a PDA just from the unusual ‘machinery’ murmur (audio clip above). Some, especially PS and PDA can even be cured or improved by surgery at a cardiac specialist.

Causes of Murmurs In Adult Dogs

There are only two common reasons in Adelaide for acquired murmurs in older dogs:

1. Degenerative Mitral Valve Disease: a progressive leak in the valve between the left atrium and ventricle. This is the classic loud murmur of old small dogs that gradually worsens with age. Read about the recent treatment advances here.
2. Dilated Cardiomyopathy: thinning and ballooning of the heart muscle, especially common in large breed dogs. Sometimes the murmur can be quiet even when the problem is severe.

Both of these can be successfully managed if monitored closely and treated early.

Causes of Murmurs in Kittens

In order, the three most common causes of heart murmurs in shelter kittens are:

1. Ventricular Septal Defect
2. Aortic Stenosis
3. Hypertrophic Cardiomyopathy: a heart disease where the muscle becomes enlarged and thickened

Around 1 in 300 kittens have a murmur. It’s likely that purebreds get other diseases as well such as valve defects and dilated cardiomyopathy.

Causes of Murmurs in Adult Cats

Acquired murmurs in older cats are almost always caused by heart muscle diseases called cardiomyopathies. We see three sorts:

1. Hypertrophic: the most common, especially with thyroid problems or older male cats.
2. Restrictive: an inflexible heart, probably with a similar cause to hypertrophic.
3. Dilated: like the dog disease, especially in Maine Coons and Ragdolls.

Max, by the way, will be just fine.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here. The information provided here is not intended to be used as a substitute for going to the vet. If your pet is unwell, please seek veterinary attention.

The world’s longest living pet cat was a Maine Coon called Ludo, who is a phenomenal 118.3cm long.

The world’s tallest living female dog was a 96.4cm Great Dane.

Why do these cute facts make all vets shudder?

What’s Wrong With Great Danes?

Here is what a Great Dane was once like. Once upon a time, Great Danes were just large hunting dogs. Then they got well known and the breed was quickly selected for certain features and larger size.

Note the broad chest, stocky build and minimal jowls. Ignore the artificially cropped ears.

Below is a classic example of a modern Great Dane, like the ones we see here in Adelaide. He’s a fine specimen but he’s come a long way from how his breed began.

The increased height and deep, narrow chest are thought to be at least partly why they are now known for:

• Osteosarcoma (Bone Cancer)
• Dilated Cardiomyopathy
• Gastric Dilation Volvulus (Bloat)

Bloat is now such a problem that many young Great Danes get a preventative gastropexy. This abdominal surgery attaches the stomach to the chest wall to stop it rotating.

I’ve said it before: giant breed dogs don’t age faster than other dogs, they die younger. Lifespan data for dog breeds show Great Danes live to only 6 to 8 years of age, versus 13 for cross breeds.

In fact, Zeus, the world’s tallest dog ever was a Great Dane that lived to only 5 years old. This should be a scandal, not a cute fact. I have no doubt (though it’s untested) that the taller we breed them, the shorter they’ll live on average.

Read common inherited diseases of other dog breeds here.

What’s Wrong With Maine Coons?

Maine Coon cats have undergone a similar selection for size from when they were just large American barn cats to the gigantic cats that can be seen today.

Maine Coons are great cats, full of personality. However, just like in Great Danes, the story of their growth has been sad one for their health.

• Hypertrophic cardiac disease has become common in the breed
• Hip dysplasia, unheard of in other cats, can be found in up to half of Maine Coons
• Lifespans are 3 years below the average for other cats

In fact, the world’s longest cat ever was a Maine Coon called Stewie that only lived to 8 years old. It’s appalling that no one is making the link between these lifespans and their size.

What’s Going Wrong?

Breed standards set the guidelines that breeders and show judges use to select the best animals. Unlike for most dogs, the standard for Great Danes only sets a minimum height. The standard for Maine Coons does not specify size despite it being their obvious claim to fame.

The lack of a maximum height, weight or length means that breeders are encouraged to breed for more extreme and noteworthy individuals, whether to win shows or achieve success elsewhere. You’ve only got to look at the competitions for largest, tallest or longest pet to see how much it matters to people.

They are probably ignorant of the true cost of breeding animals for body shapes like these.

Breeding for single spectacular traits also means other, more important, traits like fitness and resistance to disease are being overlooked. I had the pleasure of watching the German Shorthaired Pointer judging at the Royal Adelaide Show this year. I enjoyed it so much because a big part of the judging was the dogs being run, and run, and run. You won’t easily hide a bad heart or hip dysplasia with testing like this. Is it any wonder this is a healthy breed?

What I say about Maine Coons and Great Danes could be said of many other cases of exaggerated features being selected by animal breeders. Here’s what I’ve said before about Shar Pei and Scottish Fold breeding practises. All these breeds are beautiful animals being treated unfairly. It’s up to us to say no to extremes.

Cat breed lifespan data taken from O’Neill, D. G., Church, D. B., McGreevy, P. D., Thomson, P. C., & Brodbelt, D. C. (2014). Longevity and mortality of cats attending primary care veterinary practices in England. Journal of feline medicine and surgery, 1098612X14536176.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.