COMPARATIVE M-MODE ECHOCARDIOGRAPHIC STUDY OF MALE AND FEMALE DOGS WITH DEGENERATIVE MITRAL VALVE DISEASE (DMVD)

In 2005 researchers examined a sample of 317 dogs with radiologically diagnosed heart disease, and provided their percentage distribution as follows: 225 dogs (70.98%) had mitral insufficiency, 54 (17.03%) had dilated cardiomyopathy, 28 (8.83%) had cor pulmonale, 5 (1.58%) had pericarditis, 3 (0.95%) had arterial stenosis and 2 (0.63%) had pulmonary artery stenosis. Based on these data, they confirm the assertion by many other authors that mitral insufficiency is the most common heart disorder among dogs. A strong predisposition to this disease is seen among small and medium-sized dog breeds. Mitral insufficiency was diagnosed in 211 out of a total of 238 dogs belonging to these breeds (88.66%) and only in 14 of 79 large breed dogs (17.72%). In the group of small and medium breed dogs the incidence of the disease was higher among male animals (58.77% male, respectively 41.23% female) (10). In addition, males have a tendency for a faster progression of heart failure (4). Just recently, one study found a significant relationship between MR and gender in terms of mortality (P = 0.035) (6). The study showed that male dogs with moderate to severe MR had a higher mortality rate than males without MR. The researchers do not establish such a relationship in females. The severity of this cardiac disorder is also related to many other factors, for example, a study had shown that weight gain in dogs with myxomatous valve degeneration is associated with the survival rate of the animals where the longer surviving dogs are those with increased body mass (9). These facts show that the development of heart failure in case of MVD is a multifactor process.