Congestive Heart Failure (CHF)

As heart disease gets worse in dogs, this can lead to fluid building up in the lungs. This makes it difficult to breathe. This is an urgent (and potentially an emergency) condition and needs urgent treatment. The good news is, there is usually treatment that we can give to make your dog feel better. This information guide will help you understand the condition and help you treat and monitor your dog.

What is Congestive Heart Failure?

Worsening heart disease in dogs (either a leaky heart valve or weak heart muscle) can result in fluid building up in the lungs - this is called Congestive Heart Failure, or CHF. I don’t like this term, as the word “Failure” sounds like nothing more can be done. Ultimately, it just means your dog’s heart is struggling to cope with the underlying valve or muscle disease. Of course, as the amount of fluid in the lungs gets worse, this can result in severe difficulty breathing, which can become life-threatening if not treated.

How do we look out for CHF?

As fluid in the lungs makes breathing more difficult, then your dog’s breathing will get faster and often deeper. As such, a great, cheap and accurate way of monitoring your dog is by checking their breathing rates. This is best done when they are sleeping (as breathing rates increase when they are awake, and even more so when they are excited/exercising). Try and do this at the same time each day, when your dog has been asleep for 20 minutes or so. Count how many times your dog’s chest rises in 30 seconds (note that your dog’s chest will move up once and down once in each breath) - double your number to get a breathing rate per minute. In most dogs, a normal rate is less than 20 breaths per minute. We get concerned if the rate is above 30 breaths per minute. Any dog will occasionally have a rate over 30 breaths per minute (eg if they are dreaming, or really hot). Dogs with CHF tend to have a gradual increase in their breathing rates over a number of days, and this is sustained. If your dog’s breathing rate is consistently over 30 breaths per minute, then you should contact your vet ASAP. This may have to be an urgent or emergency appointment if you are concerned. There is also a free app you can download on your phone (search “Cardalis”) to help you measure and record the breathing rates; you can then show these to your vet at recheck appointments.

You can watch a video on how to measure breathing rates here: https://vetmedin.co.uk/resting-respiratory-rate

As a note, a lot of smaller breed dogs will have a cough as their heart gets bigger. Usually we do not use the cough to determine if there is fluid in the lungs as they can cough whether they do or do not have fluid buildup. If the cough becomes concerning, make an appointment to see your vet.

How do we know if my dog has fluid in the lungs?

The way to tell if there is fluid buildup is to look for it - most commonly we would do this with an ultrasound (not requiring sedation) or with a chest X-ray (often requiring a light sedative). Sometimes we may trial treatment if we are highly suspicious of the presence of fluid.

How do we treat the fluid?

The fluid in the lungs (CHF) sits inside the lungs, much like water inside a wet sponge. This means it cannot be physically removed using a needle. So we use medicines called diuretics (also known as “water tablets”). There are various different types, most commonly either furosemide (aka frusemide, Libeo) or torasemide (aka torsemide, Upcard, Isemid). These will help get rid of the excess fluid; the body does this by weeing out the excess fluid. To compensate, your dog will drink more water (this is normal). These medications will continue for life, although we will vary the dose depending on how your dog is doing. Higher doses are often required at the beginning to get rid of the fluid and then we may be able to lower the dose longer term. Frequent check ups are required in order to make sure the medications and the doses are correct. Sleeping breathing rates will usually reduce back down less than 30 breaths per minute once the fluid in the lungs is under control. Continue to count breathing rates every day forever as this will help us adjust the diuretic doses. As always, let your vet know if the breathing rates go back up to regularly over 30 breaths per minute.

You should make an appointment earlier if you notice your dog not doing as well (eg worse breathing, lethargic, not eating etc). When we use higher doses of these diuretics, this causes lots of weeing, and therefore sometimes your dog may have an accident in the house. This is only likely at the very beginning of the treatment; if it continues to happen, then let us know and we may adjust the dose or the timing of the tablets to make sure your dog has time to wee out the excess fluid before bedtime. For example, if your dog is on twice a day medication (eg furosemide), then we may give the evening dose earlier at 4pm. If your dog is on once a day medication (eg torasemide or furosemide), then we may give the tablet in the morning rather than the evening.

What happens then?

Our aim is to make sure your dog is happy and well. Every dog is going to need lifelong treatment of some sort, so don’t stop giving the tablets unless you are specifically told to. We fully expect ups and downs, so if your dog isn’t doing well, then make an appointment so we can see what is going on and how we can help; there is often lots we can do. Of course, over time, the leaky valve continues to get worse and at some stage the amount of fluid in the lungs will continue to get worse despite the treatment. If we cannot make your dog feel better, then this is when we would discuss what your dog’s quality of life is like and whether we should discuss euthanasia before they start to suffer. For more challenging cases, or if you want more advice, your vet may recommend an appointment with a Cardiologist (either in your practice, or by visiting a Specialist hospital).

Is there anything else I can do?

When there is a buildup of fluid in the lungs, keeping your dog rested for a week or so can help the heart and lungs work better. Once they are feeling better then you can slowly increase the exercise again, depending on what your dog can manage. Avoiding high-salty (high sodium) foods and treats can also help to reduce the risk of worsening fluid in the lungs. Fluid also gets worse in the hotter weather, especially when it has been very hot for a number of days. Keeping your dog cool and avoiding walking when it is hot weather can help.

In humans, the treatment for a leaky valve will often involve an operation. These are starting to become more available in the UK, but is an extremely technical operation and as such, there are only two places in the country that do this. As you’d expect, they are also very expensive (approximately £12-25,000); have a chat with your vet if this is something you are interested in finding more about.