MAGNESIUM STATUS AND THE EFFECT OF MAGNESIUM SUPPLEMENTATION IN FELINE HYPERTROPHIC CARDIOMYOPATHY

Magnesium deficiency has been associated with the development of cardi ovascular disease in several species, Cats may be predisposed to alter ations in magnesium status because of recent changes in the compositio n of commercial feline diets, The purposes of this study were 1) to ex amine the dietary history of cats with hypertrophic cardiomyopathy (HC M), 2) to study magnesium status of cats with HCM compared to normal c ats, and 3) to determine the effects of magnesium supplementation in c ats with HCM. In part 1 of the study, diets of 65 cats with HCM were e xamined retrospectively. Forty of the 45 cats for which diets could be determined (89%) ate a diet designed to be magnesium-restricted and/o r to produce an acidic urine, In part 2 of the study, 10 cats with HCM were compared to 10 healthy control cats for serum creatinine and mag nesium; urine creatinine and magnesium, urine specific gravity and pH, and fractional excretion of magnesium, Urine creatinine and specific gravity were higher in control cats than in cats with HCM. No other di fferences were found between the 2 groups, In part 3, cats with HCM we re supplemented with either 210 mg magnesium chloride (n = 15) or 210 mg lactose (n = 15) for 12 wk, No differences between the 2 groups wer e found for changes in either magnesium status or echocardiographic pa rameters, However, the 30 cats with HCM, as a group, did show signific ant improvements in measures of cardiac hypertrophy over the 12-week p eriod, This was likely the result of treatment with other medications, rather than the magnesium supplementation. The results of this study suggest that cats with HCM are likely to be fed magnesium-restricted d iets, but that they do not appear to have altered magnesium status com pared to healthy controls.