When dogs have a heart murmur, their hearts can become enlarged and lose the ability to pump blood into their lungs and the rest of their body. Known as heart failure, the symptoms show up as coughing and difficulty in breathing due to both the accumulation of fluid in the lungs and the enlarged heart pushing on and irritating the trachea.
Other symptoms of heart failure include lethargy, persistent loss of appetite, a swollen belly and pale/bluish gums.
Because coughing is a symptom of multiple other conditions, it is vital to differentiate the cause. Dogs in heart failure need immediate evaluation and medications, while dogs that are coughing but not in heart failure are less likely to need urgent care.
An easy and useful way to distinguish a cough due to heart failure versus another cause (which may include fungal infections, kennel cough or heartworms, to name a few) is to monitor the sleeping respiratory rate.
Sleeping respiratory rate is the rate, or times per minute, that your dog breathes in one minute while in a complete state of rest, meaning he or she is completely relaxed or even asleep. Research shows that dogs in heart failure have elevated sleeping respiratory rates, while dogs that are not in heart failure have normal respiratory rates.
To determine the sleeping respiratory rate, watch your dog take a breath and then exhale. Count the breaths in 15 seconds and multiply this by four to achieve the breaths per minute. If the rate consistently increases to above 40 breaths per minute, and he or she is coughing and has a suppressed appetite, contact your veterinarian immediately. You will want to set up an evaluation within 24 to 48 hours.
For assistance in accuracy, we recommend using an app such as this one.
The cardiology service at CARE focuses on the diagnosis and treatment of heart disease in dogs and cats. Animals can develop heart disease at any age. Some diseases may be quite mild and only require intermittent monitoring, but others can be quite serious and require medications and frequent monitoring both at home and at our hospital.
Our focus is on helping pets maintain a good quality of life. We educate owners about their pet’s disease so that we can work as a team to keep them feeling good and enjoying life. If you suspect that your dog is suffering from heart failure, call your vet immediately and ask to set up an appointment with our specialists.