Your cat’s heartbeat is one of the sweetest sounds you can hear. However in some cases, a veterinarian may listen to a cat’s heart with a stethoscope and hear an abnormal sound -- otherwise known as a heart murmur. A heart murmur occurs when there is turbulent blood flow in the heart as a result of structural problems or other health issues. Many murmurs are harmless and your cat can live a healthy life without any treatment, but other cat heart murmurs may indicate a more serious underlying health condition.
Causes of Heart Murmurs in Cats
Heart murmurs are caused by turbulent blood flow within the heart. This type of disturbed flow can be the result of structural problems within the heart (i.e., heart disease) or an “extracardiac” problem (not associated with heart disease).
Structural problems within the heart that can cause a heart murmur include:
- Leaky or malfunctioning heart valves
- Abnormal hole between heart chambers or arteries
- Narrowing or thickening within a chamber or vessel that blood needs to move through
Structural heart problems are either congenital (meaning the cat was born with a faulty heart) or acquired later in life.
Extracardiac problems that can cause what is referred to as a “functional heart murmur” include:
How Are Heart Murmurs in Cats Detected?
The majority of heart murmurs are detected when your veterinarian listens to your cat’s heart at their annual exam. Not all murmurs sound the same, and they are graded by intensity on a scale of I to VI, with I being very quiet and VI being very loud. The intensity of your cat’s murmur will not necessarily indicate its severity. Your veterinarian will also characterize the murmur based on when it occurs during the heart cycle as well as its location in the heart. All of these factors, in addition to any other symptoms your cat may be exhibiting, will help your veterinarian determine what is causing the murmur.
An “innocent” or “psychological murmur” is one that has no impact on your cat’s health. These murmurs are generally low intensity, and often show up in young kittens (who will usually outgrow the murmur). Adult cats can also develop this type of murmur during stressful situations (like visits to the vet). These murmurs are usually not accompanied by any other symptoms, and your veterinarian may ask to reexamine your kitten or cat in a few weeks’ time to see if the murmur has changed or disappeared.
On the other hand, murmurs caused by structural heart disease or extracardiac problems will usually have accompanying symptoms that suggest a more significant health issue. Symptoms can vary and may not show up right away, but the most common include:
Further diagnostic testing will take place if your veterinarian suspects that the murmur is being caused by structural heart disease or extracardiac problems. Depending on your cat’s symptoms, recommended testing may include x-rays, an echocardiogram (ultrasound of the heart), an electrocardiogram, and blood tests.
Heart Murmur Treatment
The underlying cause of the murmur will determine what treatment -- if any -- is appropriate for your cat.
Innocent or physiological murmurs are not treated; however, your veterinarian may continue monitoring the sound.
If the murmur is the result of an underlying health condition, that condition will be treated.
The prognosis for heart murmurs varies greatly. Since a veterinarian is the only one who can hear and diagnose a murmur, it is incredibly important to keep up with your cat’s annual health care. In the case of structural heart disease or extracardiac problems, a routine trip to the vet could save your cat’s life.
More on Cat Health
What Can Affect a Cat's Lifespan?
The Best Senior Cat Pet Supplies
5 Common Cat Problems and Health Issues
This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.