Literature review of the most reported cardiac pathology in canines in veterinary medicine; Myxomatous valvular degeneration is the most common acquired heart disease in the canine species, studies carried out in the last decade have been numerous, determining that it is a pathology of high casuistry in veterinary clinics, which represents approximately 75% of cases of emerging heart disease 90% to geriatrics with greater predisposition in those under 20 kg and some breeds such as the Cavalier King Charles Spaniel, Poodle, Shih Tzu and Dachshund. Due to its high casuistry, it is important to know the clinical characteristics, the form of presentation, the current diagnostic methods such as echocardiography, radiography, among others, classify the patient according to the American College of Veterinary Internal Medicine (ACVIM) to establish the treatment according to the stage of the disease, however, pimobendan remains the drug of choice for myxomatous valvular degeneration.