Top 10 Most Common Causes of a Dog Heart Murmur

Anemia occurs when there is not enough hemoglobin (red blood cells) circulating in the bloodstream. With younger dogs, anemia can be caused by an infestation of intestinal worms, fleas, ticks, or other parasites.

Heartworm disease is caused by the parasitic worm Dirofilaria immitis which is spread to dogs through mosquito bites. After entering the host, the adult worms will settle in the heart, blood vessels, and lungs causing heartworm disease.

Heart murmurs are very common in dogs and humans during pregnancy. This is sometimes attributed to the increased volume of blood flowing through the heart while pregnant.

Hypoteinemia occurs when protein loss exceeds protein manufacturing in the body. This is usually caused by a protein-losing enteropathy, protein-losing nephropathy, impaired protein synthesis/absorption, or protein deficiency/loss.

Hypothyroidism occurs when the thyroid is underactive causes the body’s metabolism to slow down.

Dilated cardiomyopathy is the most common heart disease in dogs. It occurs when the heart muscles weaken and wear thin. This decreases the heart’s ability to contract and pump blood efficiently.

Mitral insufficiency is when the mitral valve begins to “wear out” or weaken, causing it to leak over time.

Bacterial endocarditis is a bacterial infection of a heart valve and is most commonly found in the mitral or aortic valves.

Sub-aortic stenosis is the most common of aortic stenosis heart diseases. Sub-aortic stenosis is characterized by the narrowing just below the aortic valve of the heart.

Patent ductus arteriosis is the most common congenital heart disease in dogs. It occurs when the ductus arteriosus (the arterial shunt between the aorta and the pulmonary artery) fails to constrict and leaves a passageway for blood flow.