Heart Murmurs

Any disruption of blood flow through the heart can be heard through a stethoscope. They can be heard on the left or right side of the chest depending on which side of the heart is affected. When the body detects that blood flow is disrupted, several mechanisms tell the heart it must beat faster and harder. Vessels around the heart will constrict to aid blood flow. These measures actually do more harm than good: the heart enlarges and the patient becomes hypertensive.   

In young animals, it is more common to have structural defects that are congenital. Patent ductus arteriosis, pulmonic or aortic stenosis, and Tetralogy of Fallot are all congenital abnormalities that can cause murmurs. In older pets, endocardiosis, or systemic problems such as anemia or hyperthyroidism can cause murmurs. Heartworm disease can affect any age animal and will cause murmurs in the later stages.

In many of the diseases, the animal is asymptomatic. When the murmur starts to progressively worsen as congestive heart failure ensues, the patient can cough, become lethargic, or have breathing difficulty.

In animals less than 6 months of age, no treatment is generally necessary for mild murmurs. These murmurs will probably fade over time. If the murmur is severe, then a referral to a cardiologist may be indicated. Many congenital heart abnormalities can be treated with surgery.For older animals, the murmur is usually found on a routine physical exam. Many of these patients are asymptomatic when the murmur is mild. Many veterinarians will recommend starting cardiac medications before the patient is symptomatic. This will hopefully extend the lifespan of the pet and make the heart work more effectively. If the patient is coughing or showing other signs of heart disease, medication will definitely need to be initiated. Some pets only require one pill for heart support, while others will need several medications plus a diuretic to treat fluid in the lungs or abdomen.Patients with heart murmurs who are on medication generally live very long lives and usually pass on from some other disease. These pets will need to have strict dental care as tartar will cause heart disease to progress rapidly.