Understanding the signs of a heart murmur can help you recognize signs of a cardiovascular problem in your feline friend that needs to be treated by your vet. Here, our Long Island vets discuss the symptoms and stages of heart murmurs in cats.
What is a feline heart murmur?
When your vet listens to your cat's heart with a stethoscope, they'll listen for any abnormal heart sounds, called heart murmurs. A heart murmur is caused by turbulent blood flow in the heart or the large vessels exiting the heart. This triggers an abnormal noise that your vet will be able to hear.
This may leave you wondering what your feline friend's life expectancy may be if they are diagnosed with a heart murmur, and whether stress can cause a heart murmur in cats. If your cat is scheduled to have surgery when the heart murmur is detected, you may also question whether there are any concerns about heart murmurs in cats and anesthesia.
Before we explore these factors, let's establish some basic facts surrounding heart murmurs in cats.
The Heart Murmur Grading System
Veterinary cardiologists assess and grade heart murmurs using specific ceriteria. Grades 1 – 6 are recognized, with Grade 1 being the mildest and Grade 6 being the most severe. The grading system is primarily based on how loud the heart murmur is. However, other factors such as the area over which the heart murmur is audible are also considered.
Grade 1: Essentially inaudible
Grade 2: Always focal. Readily but softly heard.
Grade 3: Regional. Readily heard; the heart murmur is moderately intense.
Grade 4: Typically wide radiation and readily heard.
Grade 5: Loud with precordial thrill and readily heard.
Grade 6: Loud with a precordial thrill and readily heard. Can be heard when your vet cardiologists lifts the stethoscope once centimeter from the thorax.
Note that the grade of the heart murmur does not necessarily relate to the degree of severity of the underlying heart problem. While some severe heart conditions may not be associated with a heart murmur, some murmurs are quite loud and may develop with relatively small defects.
Symptoms of Heart Murmurs in Cats
The most common symptoms of a cat with a clinically significant heart murmur are: poor appetite, breathing problems, pale gums, weakness, lethargy, and weight loss (or stunted growth in a kitten).
The Potential Causes of Heart Murmurs in Cats
While the presence of a murmur generally implies an underlying heart condition, murmurs can sometimes have other causes.
In young kittens, ‘innocent’ heart murmurs may be heard as an incidental finding. These are usually no longer present when the kitten is older. Anemia is another cause of heart murmurs in cats, but the cats often show other signs of lethargy and anorexia as well.
Occasionally cats are reported to have incidental murmurs as adults, which is when the blood flow within the large vessels exiting the heart may occasionally be heard as a murmur.
Can stress cause a heart murmur in cats?
Some heathy adult cats may develop an intermittent heart murmur when stress causes their heart rate to increase. This type of physiologic murmur vanishes when the heart rate returns to normal, and it does not impact the cat's health.
Heart Murmurs in Cats: Treatment Options
When a heart murmur is first discovered in a cat, an investigation will be performed to find out the underlying issue. This may involve further tests such as an X-ray of the heart or a cardiac ultrasound examination.
If however the cat is showing no other signs of a problem and is exercising normally, then your vet may suggest you come back for a second examination in a few months to reassess the heart murmur and see if it has changed.
Sometimes if the cat is well and the heart murmur is unchanged, a periodic examination will be recommended.
The only way to determine if there is any disease within the heart itself that may be causing the murmur is to perform a detailed ultrasound examination of the heart. This is completely painless and is normally performed in a fully conscious cat.
Life Expectancy of a Cat With a Heart Murmur
Even cats with a more severe murmur who have been diagnosed with hypertrophic cardiomyopathy (a cardiac disease characterized by thickening of the heart's left ventricle) can live for many years if medical treatment is effective. If a cat with a heart murmur develops congestive heart failure, they are typically expected to live between 6 and 18 months.
Veterinary Cardiology in Long Island
While your primary care veterinarian will be able to diagnose and treat a variety of health issues very well, some conditions require specialized diagnostics and care so your pet will have the best chance at a positive outcome.
This includes heart murmurs and related illnesses or diseases, congestive heart disease, congenital heart disease, cardiac tumors, arrhythmias, and more.
If your cat or dog has been diagnosed with a heart condition or you'd like one of our board-certified veterinary cardiologists to assess your pet's heart problem, feel free to contact us. While we accept referrals from primary care veterinarians, we do not require them.
Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.