Previous studies document a linear relationship between left ventricular (LV) end-systolic (ES) and end-diastolic (ED) dimension (D). To test the hypothesis that this relationship is invariant for effects of age, gender and breed, we analyzed a group of 442 dogs admitted to our clinic because of cardiac problems. The diameter of the LV was determined by using M-mode echocardiography. Employing linear regression, each group can be characterized by the corresponding regression equation, e.g. for gender: female ESD=0.89 EDD - 086 n=162 r=0.94 male ESD=0.95 EDD - 1.05 n=280 r=0.95 with ESD and EDD as cm. By using regression analysis with multiple groups, we could not detect a significant difference in slopes (p=0.064). When we tested the effect of age, the regression slope for dogs younger than 2 years differed significantly (p=0.0005) from dogs older than two years (n=163 and n=279 respectively). When checking if this effect was gender specific, only a significant difference between slopes was found for female dogs. No difference in slope was detected for breed (p=0.91) when comparing subgroups, e.g. the Doberman (n=21) and the Bouvier (n=29). We conclude that ventricular volume regulation in dogs appear to be independent of gender and breed. However, age seems to affect ventricular volume regulation and this effect is only discernible in female dogs.
|Published - 1 Dec 1996