Page 706 - Small Animal Clinical Nutrition 5th Edition

Chapter
36

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Cardiovascular Disease

Philip Roudebush
Bruce W. Keene

“Give neither advice nor salt, until you are asked for it.”
English Proverb

Chronic mitral valvular disease (endocardiosis) is by far the
CLINICAL IMPORTANCE most common acquired cardiac abnormality in dogs, affecting
more than one-third of patients over 10 years of age
Cardiovascular disease and congestive heart failure (CHF) are (Buchanan, 1992, 1977). The tricuspid valve is also frequently
common conditions in dogs and cats.The types and prevalence involved (in approximately 30% of cases), but disease of the tri-
of heart disease in dogs in the United States were characterized cuspid valve is usually less severe. Chronic valvular disease
more than 40 years ago in a survey of 5,000 dogs at the occurs with relatively greater frequency in small dogs, especial-
University of Pennsylvania (Detweiler and Patterson, 1965). ly poodles, miniature schnauzers, Chihuahuas, cocker spaniels,
Eleven percent of dogs had reliable signs of heart disease and fox terriers, Boston terriers, dachshunds, Pekingese, miniature
another 9% had possible heart disease. Congenital heart disease pinschers and whippets (Buchanan, 1977; Thrusfield et al,
has been recognized in 0.56 to 0.85% of dogs and 0.2% of cats 1985). Mitral valvular disease has been identified in more than
(Detweiler and Patterson, 1965; Harpster and Zook, 1987; 50% of cavalier King Charles spaniels in the United Kingdom,
Buchanan, 1992). These results predominantly reflect the Sweden and the U.S. (Darke, 1995; Beardrow and Buchanan,
prevalence of congenital disease in the necropsy populations of 1993). Acquired valvular disease in cats is rare.
referral institutions, and may significantly underestimate the Since 1987, the prevalence of dilated (congestive) cardiomy-
prevalence of heart diseases in the general pet population. opathy in cats has decreased markedly following the discovery
The overall prevalence of heart disease appears to be similar that taurine deficiency was the principal cause (Pion et al, 1987,
today, but comparable epidemiologic data for acquired heart 1989), and the subsequent supplementation of most commer-
disease in the U.S. are not available (Buchanan, 1992). A clini- cial feline foods with taurine. One study documented that the
cal review in Italy found heart disease in 11% of 7,148 dogs prevalence of dilated cardiomyopathy as a cause of myocardial
(Fioretti et al, 1988). One informal survey identified heart failure in cats decreased from 28% in 1986 to only 6% in 1989,
problems as the third leading cause of nonaccidental death of whereas the occurrence of hypertrophic cardiomyopathy did
dogs (MAF, 1991). The results of a more recent informal sur- not change (Skiles et al, 1990). Referral institutions continue to
vey of veterinary clinics performed by a pharmaceutical compa- observe several individual cases of dilated cardiomyopathy in
ny also suggest that the prevalence of cardiovascular disease cats each year, only a few of which are now associated with tau-
among dogs has probably not changed dramatically from these rine deficiency. Hypertrophic and restrictive cardiomyopathies
earlier estimates. a are now the most common causes of myocardial failure in cats.