Heart Valves: These may develop abnormally or degenerate (“shrivel up”) over time. Leaky valves do not close properly (for example degenerative mitral valve disease- DMVD) and stenotic valves do not open properly and obstruct blood flow (for example aortic stenosis). The abnormal blood flow creates a murmur that your veterinarian may hear with a stethoscope and this can also be seen on ultrasound.
Heart muscle: The most common heart muscle disease in dogs is dilated cardiomyopathy (DCM). This condition leads to the weakening of the heart muscle. The heart is less efficient in pumping which leads to blood pooling and leads to the dilation of the heart.
Electrical conduction disturbance: An abnormally slow, fast and/ or chaotic heart rhythm leads to circulation issues and affects the heart muscle itself in later stages. An abnormal rhythm can often be detected during a clinical examination but a veterinarian needs an electrocardiogram to diagnose which abnormal rhythm is present.
Pericardium: The pericardium is a sac that surrounds the heart. Changes within the sack prevent the heart from stretching and filling properly. The most common heart conditions in dogs are DMVD (degenerative mitral valve disease) and DCM (dilated cardiomyopathy).
DMVD: This leaky valve syndrome commonly affects small breed dogs, especially Cavalier King Charles Spaniels, and Terriers.
DCM: This is a condition that affects mostly large breed dogs (such as Newfoundlands, and Boxers) but Springer Spaniels can also be affected.
Cats and ferrets often present with cardiomyopathies (heart muscle disease) such as hypertrophic cardiomyopathy. Heart disease does not always lead to heart failure or a reduced life span. Often the heart and body can compensate for small changes, such as a leaky valve. In an early stage of heart disease owners might not even notice that the dog has a heart condition. Only in later stages when the heart enlarges, the owner may notice exercise intolerance, coughing or breathing problems at rest when fluid accumulates on the lungs (if in left-sided heart failure) or when his belly enlarges due to free fluid in the abdomen (if in right-sided heart failure). Ultrasonography will provide the owner with more information regarding the condition and staging of heart disease. It may also give a rough prognosis and will answer what treatment is necessary if any.