Back to Client Info Index

Heart Murmurs

Understanding Your Pet's Medical Diagnosis

What are heart murmurs?

Heart murmurs are vibrations caused by disturbed blood flow through the heart. These vibrations are heard as "murmurs" when the veterinarian listens to the heart with a stethoscope. The location of the murmur can provide information about the part of the heart most likely affected. The heart murmurs are graded according to how loud they sound and if they are accompanied by a "palpable thrill." A "palpable thrill" means that the vibration is strong enough that it actually can be felt through the animal's chest wall.

What causes heart murmurs?

The heart murmur is caused by the abnormal or turbulent flow of blood through the heart. The causes of heart murmurs include:

Heart valve disease, frequently the mitral or tricuspid valve
Heart disease
Congenital heart defects (present at birth)
Anemia (low red blood cell count)
Narrowing of the arteries
Hyperthyroidism (overproduction of thyroid hormone by the thyroid gland)
Heartworm disease

What are the signs of heart murmurs?

A heart murmur is a clinical sign. The animal may have no outward physical signs. Other animals will have signs depending on the underlying cause. For example, pale gums or tongue (mucous membranes) may indicate anemia; therefore, an anemic murmur is likely.

How are heart murmurs diagnosed?

The veterinarian diagnoses heart murmurs by listening to the heart and lungs with a stethoscope. Some very loud murmurs can be heard without the aid of a stethoscope. The veterinarian must differentiate murmurs from other abnormal heart sounds and from abnormal lung sounds. Complete blood counts (CBCs) may indicate abnormalities, such as anemia or inflammation of the heart. Radiographs (X-rays) help evaluate heart size and abnormalities of the blood vessels. An echocardiogram (graphic recording of the position and motion of the heart) is recommended when heart disease is suspected. An electrocardiogram (ECG or EKG, an electrical analysis of the heart) may be useful in assessing abnormal heart rhythms.

The age of the pet helps identify the cause. For example, murmurs present since birth generally indicate a congenital defect; acquired murmurs in old, small-breed dogs usually are associated with degenerative valve disease.

How are heart murmurs treated?

Treatment for heart murmurs is based on the cause of the murmur and the associated clinical signs. No treatment may be necessary for heart murmurs without any outward signs. If congestive heart failure is evident, the pet may be hospitalized; however, most pets can be cared for at home. Medications may be prescribed, depending on the underlying cause. Animals with heart murmurs should be examined periodically to monitor the murmur and to determine if the animal is developing signs of congestive heart failure.

What is the prognosis for animals with heart murmurs?

The prognosis (outcome) for the animal depends entirely on the cause of the heart murmur.

More info available at : www.VetMedCenter.com


Back to Client Info Index