Feline Heart Murmur


Years ago, a veterinarian might detect a heart murmur during your pet’s annual examination, and you might have heard the comment, “We’ll watch this.”  Not too long ago, veterinary medicine was limited in what could be done diagnostically, and effective heart medications had not been developed.  Now, with new diagnostic capabilities, new knowledge and new medications, many pets with heart disease are living longer and more comfortably than was possible previously.

There are many causes of heart murmurs, and it is impossible to know the cause, the severity or the treatability just by listening with a stethoscope. Causes of heart murmurs in cats include birth defects, valve infection (valvular endocarditis) and the list goes on, but the most common cause is Hypertrophic Cardiomyopathy (hypertrophic = thick, cardio = heart, myo = muscle and pathy = disease).  The heart muscle thickens to the point that there is very little space in the heart for blood to accumulate to be pumped.

A special ultrasound termed an echocardiogram gives us the ability to painlessly see inside the heart while it is beating and evaluate the valves and  heart muscle.  It is the best method available to determine the severity of cat heart disease.  Ultrasound is greatly preferred over x-ray for this disease because x-rays can appear normal until this condition is very advanced.  Having an ultrasound does not require anesthesia, but an occasional pet does need a calming medication.      

Echocardiograms are not commonly available in veterinary hospitals.  Animal Hospital of North Asheville is proud to be the first animal hospital in Western North Carolina to have untrasound with color flow and continuous wave doppler for advanced imaging of the heart.  Additionally, Dr. Jim Earley has taken extensive special training and has years of experience in performing echocardiograms for our patients and for referral patients from other veterinary hospitals.

It is important to detect Cardiomyopathy  before the pet develops problems. Many cats can live comfortable, happy lives for many years with medication and monitoring.  Without treatment cats can develop congestive heart failure, or fatal complications such as a “saddle” thrombus, a clot that blocks blood flow to the rear legs and is horribly painful.

Dr. Earley performing an echocardiogram on a feline patient.

Breeds more likley to develop this condition are Ragdolls, Maine Coons, Persians and American and Oriental shorthairs, but the most commonly diagnosed breed is the common domestic shorthair cat.  This condition is more common in young to middle aged cats over a year of age, but can affect any age cat.

ACTUAL CASE: Mistoffelees, (see his picture above), is one of the most striking cats that we have ever seen.  He is a 5 year old Maine Coon who weighs 18 pounds and is not overweight.  His personality is absolutely delightful.

During his Annual Comprehensive Examination, a mild heart murmur was detected.  Dr. Earley recommended an echocardiogram because this was a new murmur and because Maine Coon cats are at higher risk for Hypertrophic Cardiomyopathy.

Unfortunately, the test shows that Mistoffelees does have cardiomyopathy and also has an arrhythmia (an abnormal beat).  Because the arrhythmia is unusual, Dr. Earley recommended a consultation with a cardiologist.  Utilizing our telemedicine capabilities, his data was sent to three cardiologists who have reviewed his case and have made recommendations.  We generally receive a written report from our specialists within 1 hour.  Mistoffelees’ cardiomyopathy has been caught early which gives a better prognosis, and the arrhythmia will be monitored closely to determine if it is stable or unstable.

We all hope that Mistoffelees will continue to feel as wonderful as he does now. Medications will be initiated to treat symptoms should it become necessary.