Selected echocardiographic variables change more rapidly in dogs that die from myxomatous mitral valve disease

ObjectivesTo determine if echocardiographic measurements change at a greater rate in dogs with myxomatous mitral valve disease (MMVD) that die of cardiac mortality.AnimalsClient-owned dogs (n = 242) with MMVD of varying severity were recruited from first opinion private practice. Only dogs which died during the study period (n = 102) were included in statistical analyses.MethodsProspective cohort study comparing the rate of change of echocardiographic variables between dogs that experienced cardiac mortality and those that experienced non-cardiac mortality. Measurements were repeated approximately every 6 months and repeated measures linear models were constructed to estimate the rate of change of each variable over time.ResultsLeft ventricular (LV) end-diastolic diameter, normalized for body weight (LVEDDN) increased over time in both mortality groups. LV end-systolic diameter, normalized for body weight (LVESDN), LV end-diastolic diameter to LV free wall thickness in diastole (LVEDD/LVFWd) ratio, E wave velocity, E- to A-wave velocity ratio and left atrial to aortic root diameter ratio all increased over time in the cardiac mortality group, but did not change in the non-cardiac mortality group. MR velocity decreased over time in the cardiac mortality group but did not change in the non-cardiac mortality group. Tricuspid regurgitation jet velocity increased over time in both mortality groups. A wave velocity and fractional shortening did not change over time in either mortality group.ConclusionsSerial echocardiographic examination every 6–12 months is useful to identify dogs with progressive MMVD that are at increased risk of cardiac mortality.