Just like us, our canine and feline friends benefit from regular heart health monitoring, particularly as they get older.
Here’s more about the two most common types of canine and feline heart disease, including symptoms, diagnosis, and how we can help affected pets.
What are the most common types of heart disease in dogs and cats?
The most common heart disease in dogs is myxomatous mitral valve disease (MMVD). This involves progressive degeneration and thickening of the mitral valve within the heart, which leads to reduced heart function.
In cats, the most common type of heart disease is hypertrophic cardiomyopathy (HCM), a condition involving progressive thickening of the heart wall muscle, so that the heart becomes less able to effectively fill with blood.
What are the symptoms of MMVD and HCM?
In milder cases, affected pets may never develop any obvious symptoms of heart disease, and eventually pass away from old age or another unrelated health issue.
More severely affected pets, however, will develop symptoms of heart failure as their heart deteriorates to a point where it can no longer effectively pump blood around their body.
Dogs who have reached a moderate to severe stage of MMVD will usually show a fairly clear onset of symptoms, although the rate at which these symptoms occur will vary. Common symptoms can include:
- Decreased exercise tolerance, i.e. becoming “puffed” easily
- An intermittent cough
- Increased breathing rate and/or effort, even at rest
- A swollen tummy
- Episodes of cyanosis (purplish or bluish tongue) or fainting
In cats, symptoms of HCM are often not noted until the disease reaches a severe point, because cats are good at masking their symptoms. Some cats may present with a history of reduced activity or lethargy. Others may develop sudden respiratory difficulties (e.g. panting) or symptoms related to blood clot formation (such as sudden leg pain, coldness, and weakness)
How can MMVD and HCM be diagnosed in affected pets?
In dogs with MMVD, regular veterinary health checks can often detect the issue in the earlier stages, because affected pets usually have a heart murmur (an abnormal heart sound that can be heard with a stethoscope).
Dogs with murmurs can then be monitored for any progression in their condition via options including:
- Regular checks of their resting respiratory rate by their owners
- Sequential chest x-rays to monitor their heart size
- Referral to a specialist for echocardiogram (heart ultrasound)
Unfortunately, HCM can be a little trickier to identify in cats. This is because listening to a cat’s heart with a stethoscope is not a sensitive tool for diagnosing heart disease, as up to 70% of cats with an audible heart murmur have an “innocent” murmur (i.e. a murmur that is not a sign of actual disease), and some cats with HCM may not have a murmur at all!
For this reason, it’s recommended that any cat showing abnormal breathing undergo an urgent veterinary assessment. If you have a feline friend with a breed-related predisposition to heart disease, e.g. a Maine Coon, British Shorthair, Ragdoll or Sphynx, it’s also a good idea to have a chat with our veterinary team about options for heart health monitoring.




