ECHOCARDIOGRAPHIC EVIDENCE FOR MYOCARDIAL FAILURE INDUCED BY TAURINE DEFICIENCY IN DOMESTIC CATS

Dietary taurine-deficiency is a cause of dilated cardiomyopathy (DCM) in cats. While the incidence of clinical cases of feline DCM has marke dly decreased since the association between DCM and taurine-deficiency was first recognized, not all cats maintained on taurine-deficient di ets develop DCM. The objective was to temporally evaluate left ventric ular (LV) function using M-mode echocardiography in 23 cats maintained on a taurine-deficient diet; 20 time-matched, taurine-supplemented ca ts served as controls. The duration of feeding trials ranged from 6-15 months. No diminution of myocardial function was recorded in a small number of taurine-deficient cats whereas cardiac performance in some t aurine-deficient cats diminished to levels characteristic of DCM. Of t he taurine-deficient cats, 17 (74%) experienced a greater than 25% red uction in fractional shortening and 21 (91%) had a greater than 25% in crease in LV end-systolic short-axis diameter. On average, LV end-syst olic short-axis diameter increased by 70% and fractional shortening de creased by 37% in taurine-deficient cats. Mean velocity of circumferen tial fiber shortening was similarly reduced in taurine-deficient cats. The greatest rate of change in M-mode echocardiographic variables occ urred during the first four months on the taurine-deficient diet. Diet ary taurine deficiency leads to a spectrum of changes in myocardial fu nction in domestic cats. While DCM is observed in some cats, decreased systolic pump function and increased LV end-systolic short-axis diame ter are more consistent findings.