Use of Simpson's Method of Disc to Detect Early Echocardiographic Changes in Doberman Pinschers with Dilated Cardiomyopathy

Abstract

Background: M-mode is the echocardiographic gold standard to diagnose dilated cardiomyopathy (DCM) in dogs, whereas Simpson's method of discs (SMOD) is the preferred method to detect echocardiographic evidence of disease in humans.Objectives: To establish reference values for SMOD and to compare those with M-mode measurements. Animals: Nine hundred and sixty-nine examinations of 471 Doberman Pinschers. Methods: Using a prospective longitudinal study design. Reference values for SMOD were established using 75 healthy Doberman Pinschers 48 years old with o50 ventricular premature contractions (VPCs) in 24 hours. The ability of the new SMOD cut-off values, normalized to body surface area (BSA), for left ventricular end-diastolic volume (LVEDV/BSA 495 mL/m 2 ) and end-systolic volume (LVESV/BSA 4 55 mL/m

Simpson's Method of Discs for Measurement of Echocardiographic End‐Diastolic and End‐Systolic Left Ventricular Volumes: Breed‐Specific Reference Ranges in Boxer Dogs

“…,[ 5, 6, 14 ] In this study, suggested reference intervals for SMOD‐derived EDVI and ESVI based on data of 85 Boxer dogs are 49–93 mL/m² and 22–50 mL/m², respectively. These reference ranges are comparable to a previous study in Doberman Pinschers, where upper limits of normal for EDVI and ESVI were 95 mL/m² and 55 mL/m², respectively 11. Furthermore, the SMOD‐derived ESVI reference interval, based on data of 40 Great Danes, was 21.9–47.0 mL/m² in a recent study 12.…”

“…In contradiction to this study, the range of SMOD‐derived ESVI was below the cut‐off of 30 mL/m² (9.5–25.4 mL/m²) in a previous study including a group of 24 healthy smaller breed dogs (<10 kg) 19. Because of the large overlap between normal and abnormal values in the ESVC guidelines and several studies describing ESVI >30 mL/m²,11, 12 further study in dogs of different breeds is warranted to determine SMOD‐derived ESVI cut‐offs.…”

“…All of these breeds are predisposed to idiopathic DCM, for which diagnostic criteria have been proposed by the ESVC taskforce 21. In the ESVC recommendations, it is stated that “an ESV‐I over 80 mL/m² offers unequivocal evidence for systolic dysfunction, although this may be an excessively conservative value, as the normal canine ESV‐I has been suggested to be <30 mL/m².” The upper limit of the reference intervals for ESVI in Doberman Pinschers, in Great Danes, and in this study is clearly lower than the 80 mL/m² but higher than the 30 mL/m², suggested in the ESVC paper 11, 12. This would indicate, as previously suggested,11 that either ESVI is higher in these 3 breeds compared with other breeds, suggesting intrinsic systolic dysfunction, or the cut‐off value of 30 mL/m² is too low.…”

“…In dogs, SMOD correlated well with 3D measurements of LV volume, whereas the Teichholz formula overestimated LV volume with a factor 2 10. SMOD measurements have been shown to be more sensitive than M‐mode echocardiography for early detection of occult cardiomyopathy in Doberman Pinschers 11. SMOD reference values have been published for the Doberman Pinscher11 and the Great Dane,12 but not for Boxer dogs.…”

“…SMOD measurements have been shown to be more sensitive than M‐mode echocardiography for early detection of occult cardiomyopathy in Doberman Pinschers 11. SMOD reference values have been published for the Doberman Pinscher11 and the Great Dane,12 but not for Boxer dogs. Because of the substantial variability in echocardiographic measurements in dogs of different somatotypes,13 and the particular interest of cardiac screening in the Boxer breed, the primary objective of this study was to establish breed‐specific SMOD reference values in healthy Boxer dogs.…”