CARDIOGRAPHIC ECHODOPPLER ASSESSMENT OF AREA, VOLUME AND RIGHT ATRIAL FUNCTION OF HEALTHY DOGScanine, cardiology, echodopplercardiogramThe left and right atria have numerous functions. Accurate measurement of atrial size is critical in assessing patients for the presence and extent of heart disease. An increase in atrial size usually reflects changes in pressure or volume in a physiological attempt to compensate for an increase in atrial wall stress. The extent of right atrial dilation is often predictive of poor cardiovascular outcomes, so the importance of accurately quantifying right atrial size cannot be overemphasized. Atrial size can be assessed noninvasively using echocardiography. Echocardiography is widely available in veterinary practice and provides veterinarians with the ability to subjectively and objectively assess atrial size. Objective measurements include linear dimensions and area and volume calculations. The present study aims to evaluate the area, volume and right atrial function of healthy dogs, using echodopplercardiography. Thirty dogs, regardless of sex, lifestyle, and reproductive status, weighing up to 15kg, that do not yet have any previous heart disease and/or respiratory disease, from the Laboratory of Experimental Chemotherapy in Veterinary Parasitology (LQEPV) of the University will be included in the study. Rural Federal of Rio de Janeiro (UFRRJ). The work will be submitted to the ethics committee in the use of animals (CEUA/URRJ). The animals will be weighed and then submitted to clinical examination, with emphasis on cardiorespiratory systems. Continuing, the electrocardiographic and echodopplercardiographic exams and chest radiography will be performed to rule out respiratory diseases and the ELISA test (Snap Test 4Dx) and the modified Knott technique to rule out the presence of heartworm.