RESTING AND DOBUTAMINE STRESS ECHOCARDIOGRAPHIC FACTORS ASSOCIATED WITH THE DEVELOPMENT OF OCCULT DILATED CARDIOMYOPATHY IN HEALTHY DOBERMAN-PINSCHER DOGS

In 29 healthy Doberman Pinschers, echocardiographic parameters evaluat ing systolic and diastolic function were examined prospectively at res t and during dobutamine constant rate infusion (5 mu g/kg/minute) to d etermine if any parameters were associated with the development of occ ult dilated cardiomyopathy (DCM). A resting echocardiogram was repeate d 1 year later to determine which dogs had met our criteria for occult DCM. Six dogs developed occult DCM during the follow-up period. Univa riate logistic regression analysis showed that at rest, an increased l eft ventricular internal dimension in systole (LVID-S) (P = .02), pree jection period (PEP) (P = .03), ratio of PEP to left ventricular eject ion time (P = .02), and isovolumic relaxation time (P =.02) were signi ficantly associated with the development of occult DCM. During dobutam ine stress echocardiography (DSE), high LVID-S (P = .02) and systolic wall stress index (P = .04) and reduced fractional shortening (P =.02) and ratio of peak early to late diastolic mitral filling velocity (E/ A) (P = .05) were associated with the development of occult DCM. Multi ple logistic regression showed that LVID-S (P = .002) and E/A (P = .00 2) measured during dobutamine infusion also were associated with the d evelopment of occult DCM. Reclassification based on the DSE data was n ot significantly different than reclassification based on the resting echocardiographic data. Resting echocardiography and DSE have the pote ntial to be clinically applicable screening tests for very early systo lic and diastolic dysfunction in Doberman Pinschers, heralding the ons et of occult DCM as it is currently defined.