The article presents the results of assessing the informativeness of the improved technique of preoperative echocardiographic screening study in dwarf dog breeds. Evaluation of the ratio of the sizes of the left atrium to the root of the aorta, the pulmonary vein to the right branch of the pulmo-nary artery, normalized to the body weight of the end-systolic and end-diastolic dimensions, the fraction of the shortening of the left ventricle, the velocity of the peak E of the transmitral blood flow and the time of isovolumic relaxation makes it possible to carry out an effective preoperative assessment functional state of the cardiovascular system in dwarf dogs. These indicators do not de-pend on the body weight of dogs and characterize the state of remodeling, systolic and diastolic functions of the left chambers of the heart. Determination of the complex of these echocardiograph-ic parameters within 8-11 minutes makes it possible to assess the pumping function of the heart, to predict and reduce the risk of developing cardiogenic pulmonary edema.