Mitral Valve Dysplasia In Dogs
Mitral valve dysplasia refers to the irregular development or deformation of the mitral valve of the heart, providing a way for blood to be regurgitated back into the left atrium. Bull Terriers, German Shepherds, and Great Danes are the breeds of dogs most prone to developing mitral valve dysplasia.
Long-standing mitral regurgitation leads to enlargement of the left ventricle and atrium. With severe regurgitation, blood flow from the heart reduces, causing the affected dog to display signs of heart failure and arrhythmias. In certain cases, mitral valve defects cause stenosis, or constriction of the valve. The symptoms of mitral valve dysplasia are reliant on the complexity of the defect, with signs of left-sided congestive heart failure including coughing and problematic breathing. An electrocardiogram, chest x-rays and echocardiography can all be used to diagnose the defect.
The outlook for dogs with Mitral valve dysplasia is poor. Slightly affected animals may survive without displaying symptoms for quite a number of years.
Mitral Stenosis In Dogs
Mitral valve stenosis refers to a tapering of the mitral valve opening due to irregularities of the mitral valve. Blood inflow to the left ventricle is then blocked as a result. Although the deformity is not common in dogs, it can occur in conjunction with other inborn defects such as subaortic stenosis, mitral valve dysplasia, and pulmonic stenosis.
The effects of mitral stenosis include; an enlargement of the left atrium, an elevation in blood pressure within the veins of the lungs, fluid accumulation in the lungs, fainting due to lack of blood flow to the brain, and in some cases, a low-grade heart murmur. In the event that mitral valve dysplasia is enjoined with the stenosis, a louder murmur can be detected. X-rays, electrocardiography and echocardiography can be used not only to show the effects of stenosis, but to also corroborate the diagnosis.
Dogs suffering from this particular ailment can be prescribed diuretics and be placed on a low-salt diet. However, use of diuretics should be tracked vigilantly as it can lead to a large urine output, thus reducing blood flow from the heart. It should be noted that surgery and other treatments are not usually conducted due to the overall risk on the animal and its high cost.
Tricuspid Dysplasia In Dogs
This is a condition where there is abnormal development or deformity of the tricuspid valve of the heart, causing blood to be regurgitated back into the right atrium. Labrador Retrievers and German Shepherds are the dog breeds most likely to suffer from tricuspid dysplasia. On rare occasions, narrowing (stenosis) of the tricuspid valve is also detected.
If the tricuspid regurgitation goes on unabated, there could be effects such as overload of the right atrium, enlargement of the right ventricle and atrium, reduction in blood flow to the lungs, fatigue, and a rapid respiratory rate. Due to the elevation in pressure in the right atrium, blood collects in the veins, leading to build-up of fluid in the abdomen.
Severe defects produce severely obvious symptoms in affected dogs. Symptoms of right-sided congestive heart failure include; accumulation of fluid in the abdomen and lungs, a loud heart murmur, and arrhythmias, which may cause death. Various techniques can be useful in evaluating and diagnosing the enlargement of the right ventricle and atrium, e.g. electrocardiography and x-rays, while the abnormal tricuspid valve can be diagnosed using echocardiography.
The prognosis for dogs with these symptoms is usually 50-50. Intermittent draining of fluid from the abdomen, and medications such as diuretics, vasodilators, and digoxin, are commonly recommended.