Kostiuk O. Hypertrophic cardiomyopathy of the domestic cat (prevalence, prognosis and risk factors)

This study describes the overall prevalence of hypertrophic cardiomyopathy among asymptomatic cats and cats with signs of congestive heart failure. The study was performed in veterinary clinics in Kyiv. The prevalence of cardiomyopathies in 315 cats was studied. Among them, 65 % are female, and 35 % are male domestic cats. The average age of the animals was 4.5 years (from 2 to 14 years), the average body weight was 4.2 kg (from 2.2 to 8.3 kg). According to the echo-results, heart disease was detected in 14 % of domestic shorthair cats, 2.8 % of cats had changes that may indicate the early stage of hypertrophic cardiomyopathy (suspicious for the presence of heart disease or grey zone). Most cats in symptomatic hypertrophic cardiomyopathy was males – 60 %. The assessment of the prevalence of hypertrophic cardiomyopathy in British and Scottish Shorthair cats was carried out. It was established that in Kyiv city, British shorthairs is susceptible breed. It was found that the prevalence of the disease in this breed is 24 %. Also was studied the complications of hypertrophic cardiomyopathy – cardiogenic pulmonary edema in 90 cats. The mortality rate in intensive care unit was 46 %. 11 % of cats were diagnosed with complete or partial arterial thromboembolism as additional complication. The mortality rate of cats in this group was much higher – 80 %. The significance of the lung damage severity was studied. A scoring system from 1 to 4 was created and investigated. It was found that in cats that died in intensive care unit (experimental group), the lung damage degree is higher, compared to control group animals. According to the score system 50% of the cats in the control group had a mild degree of lung damage (2 points), while 74 % of animals in the experimental group had 3–4 points, the difference is reliable p<0.001. The study, the four-year survival was determined in cats with different phenotypes. Also was investigated the impact of risk factors on their life expectancy. Data analysis of 315 cats from the first stage of the study and 40 cats that survived after pulmonary edema was performed. The total number of examined animals was 355 cats. We found 27 % cats with cardiomyopathy. Hypertrophic cardiomyopathy was diagnosed in 80 % of the animals. Other forms of cardiomyopathy were less common: 13 % had restrictive cardiomyopathy, 4 % of cats were diagnosed with non-specific cardiomyopathy and 3 % with dilated cardiomyopathy. It was determined that the probability of survival in the first year of life of cats after the diagnosis of hypertrophic cardiomyopathy is 86 %. Animals die most often in the 2nd and 3rd year after diagnosis. The survival probability in the second year of life after the diagnosis is 50 %, while in the third year survival drops to 15 %. It was found that the average age of cats in control group was higher compared to the cats in experimental group (respectively 6 and 4.8 years). Among cats that died, more animals had signs of congestive heart failure (86 %), gallop rhythm was more common during the examination (66 %). This sound forms as an additional tone only with severe elasticity changes in the interventricular membrane and indicates increased stiffness of the myocardium.