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Congestive Heart Failure

Congestive heart failure (CHF) occurs from severe heart disease. In left sided CHF, the left atrium has become severely enlarged from the underlying disease process. As the pressure of blood inside the left atrium starts to elevate, the pressure backs up along the vessels draining blood from the lungs. If this pressure gets high enough, fluid can leak out into the air sacs. This is called pulmonary oedema and means your dog has developed congestive heart failure. This is a life threatening condition that requires prompt treatment. Signs of congestive heart failure include an increased breathing rate and effort, lethargy, poor tolerance to exercise, reduced appetite and, occasionally, collapse. The goal of treatment for CHF is remove the pulmonary oedema with medication and maintain a good quality of life for your pet.



  1. Frusemide. This is a diuretic that causes increased urination to remove excess fluid from the body. Frusemide is the most important drug in congestive heart failure and the best drug for removing pulmonary oedema from the lungs. It will cause your dog to drink and urinate more so please make sure there is always plenty of water available and easy access to outdoors.

  2. Pimobendan (Vetmedin). This drug helps the heart pump better and increases survival. Side effects are rare but the occasional dog can develop anxiousness. Diarrhea can occur in the rare dog as well.

  3. Benazepril (Fortekor). Drugs in this class (ACE inhibitors) stop the kidneys from retaining more fluid. Side effects are rare but if your dog stops eating and starts vomiting after starting this drug, please stop this drug and contact us.



Sleeping RR

It is very important to monitor your pets sleeping respiratory rate daily once they have congestive heart failure, as this is the easiest and quickest way to pick up recurrence of pulmonary oedema. The sooner this is diagnosed, the easier it is to treat and the quicker the response. While sleeping, count the number of breaths your pet takes over 15 seconds then multiply by 4 to get breaths/minute. Record this number in an exercise book daily or on your smartphone using the Cardalis app. A normal sleeping respiratory rate is < 30 breaths/minute. If your pets respiratory rate is consistently over 40 breaths/minute, please have him or her re-evaluated as a higher dose of frusemide will likely be required. However, if your pets respiratory rate becomes > 60 breaths/minute or there is marked effort, please have him or her evaluated by a vet immediately as this may be a medical emergency. 


Chest Xrays

Chest xrays are often taken to assess if pulmonary oedema is present. If your pet develops an increased respiratory rate or effort, this test will likely be recommended.


Blood work

Some of the drugs used to treat CHF can affect the kidneys. This becomes especially important in the later stages of the disease when high doses of multiple drugs are used. A blood kidney panel will often be recommended at the onset of CHF then more frequently in the later stages of the disease when drug doses are being increased.



If you pet stops eating and drinking for any reason, the diuretics used to remove the excess fluid in heart failure can cause severe dehydration.  Please contact us or your regular vet if your pet has not eaten or drank for 24 hrs while on treatment for CHF. It is common for the appetite to reduce and your pet to become very picky in the later stages of the disease. Tempt feeding and changing food frequently is often required at this stage.

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