Types of Heart Murmurs in Cats
Heart murmurs in cats are diagnosed through a physical examination using a stethoscope, grading the heart murmur based on severity, and identifying what type of heart murmur is occurring based on the heart’s sound. An electrocardiogram may help to distinguish the grade and type of heart murmur, and complete blood tests and ultrasound examinations can be used to determine why the heart murmur is occurring.
There are many different types of heart murmurs, and they are distinguished by their specific sounds that occur on an up or down beat and by their intensity. In many cases, it is difficult to determine exactly what the heart is doing by sound alone, and an echocardiogram (ECG) is often used to get a view of the heart’s patterns.
Heart murmurs can be caused by a variety of conditions, and blood tests and ultrasound examinations are often used to determine if a treatable medical condition is causing the murmur, or if the murmur is caused by a physical defect in the heart or an inherited genetic condition.
Grading the Severity of Heart Murmurs in Cats
Heart murmurs are diagnosed based on grades one through six.
- A grade one heart murmur is the least severe and it can barely be heard.
- A grade two heart murmur is a faint murmur that occurs only in a specific area of the heart.
- A grade three heart murmur can be heard immediately once an examination with a stethoscope begins and the sound is widely projected.
- A grade four heart murmur can also be immediately heard during an examination and it is accompanied by a vibration known as a thrill
- A grade five heart murmur is the loudest murmur
- A grade six heart murmur can still be heard when the stethoscope has just been removed from the chest wall
Treating feline heart murmurs is not a realistic or viable option, because heart murmurs are not a disease or illness but rather are simply abnormal heart sounds caused by turbulent blood flow. To “treat” the heart condition, the veterinarian must identify why the murmur exists. Once the cause of the murmur is identified, a treatment program can be formulated.
Treating Heart Murmurs in Cats
Heart murmurs can be congenital (the animal is born with them) or acquired, and the prognosis ranges from excellent to grave, depending on the underlying cause. Available treatment options will vary depending upon the severity of the underlying condition. Many feline heart murmurs do not require “treatment” at all, even if the murmur is very pronounced. Minor heart murmurs can often be addressed by dietary and lifestyle changes without more.
The most common causes of heart murmurs in companion cats are hyperthyroidism and cardiomyopathy. Hyperthyroidism often can be treated or managed through surgery and/or medical regimens. Feline cardiomyopathy often is manageable as well with a combination of drugs and supportive care that will reduce the heart’s workload, increase the elasticity of the heart muscle and improve the heart’s overall efficiency. Feline heart murmurs caused by anatomical abnormalities may be surgically correctable. Many pet owners are unable or unwilling to proceed with these specialized surgeries, but interested cat fanciers should explore all treatment and management options with their treating veterinarians. Heart murmurs in cats can also be caused by severe anemia from internal or external parasite infestation. Appropriate flea and tick preventative protocols and deworming regimens can be discussed with your veterinarian. Nutritional supplements can also help resolve the anemia and corresponding murmurs in some cases.
Cats with murmurs reflecting underlying heart disease should be kept in a warm, calm, soothing household environment where they can minimize their activity level and rest and relax as needed. In households with young children and other pets, the adults will need to carefully manage their cat’s special needs and requirements for rest.