Indices for M-mode measurements in dogs usually have been based on the assumption that a linear relationship exists between these measurements and body weight (BW) or body surface area (BSA). The relationships between the geometry of 3-dimensional objects do not support this assumption. The purposes of this study were to retrospectively examine M-mode data from a large number of dogs of varying sizes and breeds that were examined by a large number of ultrasonographers, to use the allometric equation to determine the appropriate BW exponent required to predict these cardiac dimensions, and to determine normal mean values and prediction intervals for common M-mode variables. Linear regression analyses of data from 494 dogs (2.2-95 kg) revealed a good correlation between M-mode measurements and BW after logarithmic transformation of the data (r 2 .55-.88). Most variables were most closely related to an index of body length, BW 1/3 , although the exponent that best predicted diastolic and systolic left ventricular wall thicknesses was closer to 0.25. No variable indexed well to BW or BSA. With these data, appropriate mean values and prediction intervals were calculated for normal dogs, allowing veterinarians to correctly and appropriately index M-mode values. The equations developed from this study appear to be applicable to adult dogs of most breeds.

Recommendations are presented for standardized imaging planes and display conventions for two-dimensional echocardiography in the dog and cat. Three transducer locations ("windows") provide access to consistent imaging planes: the right parasternal location, the left caudal (apical) parasternal location, and the left cranial parasternal location. Recommendations for image display orientations are very similar to those for comparable human cardiac images, with the heart base or cranial aspect of the heart displayed to the examiner's right on the video display. From the right parasternal location, standard views include a long-axis four-chamber view and a long-axis left ventricular outflow view, and short-axis views at the levels of the left ventricular apex, papillary muscles, chordae tendineae, mitral valve, aortic valve, and pulmonary arteries. From the left caudal (apical) location, standard views include long-axis two-chamber and four-chamber views. From the left cranial parasternal location, standard views include a long-axis view of the left ventricular outflow tract and ascending aorta (with variations to image the right atrium and tricuspid valve, and the pulmonary valve and pulmonary artery), and a short-axis view of the aortic root encircled by the right heart. These images are presented by means of idealized line drawings. Adoption of these standards should facilitate consistent performance, recording, teaching, and communicating results of studies obtained by two-dimensional echocardiography. nary Internal Medicine (ACVIM) has recognized the need to adopt profession-wide standards for nomenclature, display and recording, interpretation, communication, and publication of images obtained using this technology. Accordingly, a Committee on Echocardiography, composed of experienced veterinary cardiac ultrasonographers, was formed to produce a report of recommendations for standards in veterinary echocardiography. This report, one of several to be developed by the committee, contains recommendations for standards for routine transthoracic two-dimensional echocardiography (2DE) in the dog and cat. The principles are generally applicable to other species, including horses and other farm animals, but more study and experience will be required before detailed recommendations can be made for these species. The recommendations presented in this report have been reviewed and approved by consensus of the diplomates of the Specialty

Indices for M-mode measurements in dogs usually have been based on the assumption that a linear relationship exists between these measurements and body weight (BW) or body surface area (BSA). The relationships between the geometry of 3-dimensional objects do not support this assumption. The purposes of this study were to retrospectively examine M-mode data from a large number of dogs of varying sizes and breeds that were examined by a large number of ultrasonographers, to use the allometric equation to determine the appropriate BW exponent required to predict these cardiac dimensions, and to determine normal mean values and prediction intervals for common M-mode variables. Linear regression analyses of data from 494 dogs (2.2-95 kg) revealed a good correlation between M-mode measurements and BW after logarithmic transformation of the data (r 2 ϭ .55-.88). Most variables were most closely related to an index of body length, BW 1/3 , although the exponent that best predicted diastolic and systolic left ventricular wall thicknesses was closer to 0.25. No variable indexed well to BW or BSA. With these data, appropriate mean values and prediction intervals were calculated for normal dogs, allowing veterinarians to correctly and appropriately index M-mode values. The equations developed from this study appear to be applicable to adult dogs of most breeds.Key words: Canine; Echocardiography; Heart; Reference range. M-mode echocardiography is commonly used to measure linear cardiac dimensions of cardiac chambers, walls, and great vessels. Because adult dogs range in weight from Ͻ2 to Ͼ90 kg, any definition of normal heart size must take into account the variation caused by differences in body size. Consequently, it is important to identify equations that accurately describe the relationships between body size and cardiac dimensions. Several authors have published equations, nomograms, or tables that are intended to be used as reference ranges for M-mode measurements for adult dogs of varying size and breed. [1][2][3][4][5][6][7][8][9][10][11] Critics have questioned the usefulness of some of these reference ranges because of small sample sizes, lack of data points for the extremes of body size, wide prediction intervals, and the use of inappropriate statistical methods. 5,[10][11][12][13][14][15] In addition, many authors have assumed that a linear relationship exists between linear cardiac dimensions and either body weight (BW) or body surface area (BSA), which might not be true. Evidence also has been presented suggesting that a general equation might never be accurate because breed is a factor Davis, CA 95616-8747; e-mail: cccornell@ucdavis.edu. Submitted March 7, 2003; Revised July 1 and October 31, 2003; Accepted December 11, 2003. Copyright that can cause M-mode measurements in dogs of the same weight to differ. 13The statistical methods used to produce the previously mentioned reference ranges were not described in every case, but in 2 studies in which the authors detailed their methods, reference ranges we...

Background: Myxomatous mitral valve disease (MMVD) continues to be an important cause of morbidity and mortality in geriatric dogs despite conventional therapy.Hypothesis: Pimobendan in addition to conventional therapy will extend time to sudden cardiac death, euthanasia for cardiac reasons, or treatment failure when compared with conventional therapy plus benazepril in dogs with congestive heart failure (CHF) attributable to MMVD.Animals: Two hundred and sixty client-owned dogs in CHF caused by MMVD were recruited from 28 centers in Europe, Canada, and Australia.Methods: A prospective single-blinded study with dogs randomized to PO receive pimobendan (0.4-0.6 mg/kg/d) or benazepril hydrochloride (0.25-1.0 mg/kg/d). The primary endpoint was a composite of cardiac death, euthanized for heart failure, or treatment failure.Results: Eight dogs were excluded from analysis. One hundred and twenty-four dogs were randomized to pimobendan and 128 to benazepril. One hundred and ninety dogs reached the primary endpoint; the median time was 188 days (267 days for pimobendan, 140 days for benazepril hazard ratio 5 0.688, 95% confidence limits [CL] 5 0.516-0.916, P 5 .0099). The benefit of pimobendan persisted after adjusting for all baseline variables. A longer time to reach the endpoint was also associated with being a Cavalier King Charles Spaniel, requiring a lower furosemide dose, and having a higher creatinine concentration. Increases in several indicators of cardiac enlargement (left atrial to aortic root ratio, vertebral heart scale, and percentage increase in left ventricular internal diameter in systole) were associated with a shorter time to endpoint, as was a worse tolerance for exercise.Conclusions and Clinical Importance: Pimobendan plus conventional therapy prolongs time to sudden death, euthanasia for cardiac reasons, or treatment failure in dogs with CHF caused by MMVD compared with benazepril plus conventional therapy.