Dog Heart Murmur

" Dog heart murmur is the term used for hear-able vibrations produced by the heart or major blood vessels, due to a troubled flow of dog blood. Heart murmurs in dogs can also be produced due to any abnormality in a dogs cardiac features, such as the heart valves, cardiac leaflets or chordal structures. Canine heart murmurs can be minor or a normal cardiac behavior. A dog cardiac problem should be suspected in cases where there are accompanying symptoms such as lethargy, intolerance, obesity, cough, fainting and irregular breathing. Heart murmurs are important as part of a clinical examination for any dog heart disease, but confirmation of any underlying condition requires detailed procedures such as X-Rays, blood profiles, electrocardiography etc. Treatment for dog heart murmur is dependent upon a confirmatory diagnosis and requires either a specific surgical or medical approach along with a supportive care. "

Pathology of a Canine Heart Murmur:

Dog heart murmur is often minor in nature, a dog heart condition which is called a “physiological murmur” or “innocent murmur”. This kind of dog heart murmur is usually produced on the outer surface of the heart or major blood vessels, which is caused by blood pressure blood on walls of the heart.  These are usually puppy heart murmurs which resolve by the time the dog reaches 6 months of age. Minor dog heart murmurs is also found in large and giant breed dogs, in dogs that are athletes, and during illnesses such as canine hypoproteinemia (low levels of blood protein), anemia and fever.

Physiological heart murmurs are hard to hear and are usually only noticed when a dog is panting after exercise, fear, excessive barking or running. On the other hand, a “pathological murmur” is a clearly audible cardiac vibration, which is produced inside the heart or major blood vessels due to troubled blood flow. Blood flow can be abnormal due to any problem in the valves, cardiac leaflets in the heart or congested blood flow in major blood vessels.

The comparison of normal to abnormal canine heart murmurs and severity of the cardiac problem is clinically analyzed on the basis of a physical examination with the help of a stethoscope and observation.

Types of Dog Heart Murmur

1. Systolic canine heart murmur: This kind of heart murmur is produced during systole or contraction of the heart. This murmur represents either an ejaculation and/or back flow of blood. Most commonly, an abnormal heart murmur can be noticed during mid-systole of a heart beat. Systolic heart murmur in dogs may representss cardiac problems such as stenosis (valve narrowing) and degeneration of the mitral valves.
2. Diastolic canine heart murmur: This kind of dog heart murmur is produced during diastole or relaxation of the heart. Diastole or relaxation of cardiac muscles ends up filling up the heart to pump through each contraction, but audible vibrations other than normal heart beat sounds may represent a serious cardiac problem such as endocarditis and/or pulmonic insufficiency.
3. Continuous canine heart murmur: Continuous canine heart murmur shows the involvement of both systole and diastolic heart murmurs, i.e. are noticed through out relaxation and contraction of the cardiac muscles. This kind of observation most commonly is present in patients with congenital heart problems and ventricular insufficiency.

For a precise analysis, a heart murmur in dogs are usually identified and related with the intensity of the murmur, timing, pitch, location, quality, frequency and configuration of different vibrations observed in a clinic, during auscultation which means "listening for sounds."

Symptoms related to Dog Heart Murmur:

Canine heart murmur is  a clinical feature of a heart patient during diagnosis. Dogs with symptoms such as cough, lethargy, intolerance, fainting, loss of appetite and irregular breathing should be suspected for possible canine heart disease. A detailed clinical examination for the identification of symptoms and procedures like auscultation (listening) of heart sounds/murmurs can reveal a possible underlying problem.

Auscultation (listening) to dog heart sounds and murmurs can help a veterinarian in identifying the severity and nature of the dog heart problem. This is a clinical feature only, confirmation can only be done through other specific features like radiography and laboratory tests.

Diagnosis of Canine Heart Murmur:

Canine heart murmurs are a clinical feature for heart patients, on the basis of which a veterinarian will recommend different procedures for confirmation of the condition. A brief assessment of possible dog heart disease can be made on the basis of auscultation, but confirmation of any underlying condition can only be made through X-Rays, blood profiles, electrocardiography and echocardiography etc.

Click to listen to a dog heart murmur:

Treatment for Dog Heart Murmur:

Once an underlying canine heart disease is diagnosed, specific treatment should be followed. Approaches can be either medical or surgical, based upon the age of a patient, the severity and nature of the diagnosis made. Canine heart murmur is a clinical feature, a symptom itself and a diagnostic tool which usually resolves on successful specific cardiac treatment.

Since, canine heart murmurs are related with abnormality in the physiology and strength of the heart muscles, valves and major blood vessels, a supportive therapy with supplements and tonics such as Heart and Circulation Tonic can help to improve a dog's clinical condition during treatment. These supplements and natural remedies can be used after recovery to maintain cardiovascular strength. Similarly, along with specific and supportive treatment, critical care is needed in the day to day routine of a dog with heart problems, such as regular use of prescribed medications and care regarding activities.

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References for Congestive Heart Failure in Dogs:

Merck Veterinary Manual (Merck & Co.)

Veterinary Clinical Cardiology