Survival Study and Assessment of Prognostic Factors in Dogs with Idiopathic Dilated Cardiomyopathy
F.L. Yamaki1; E.C. Soares1; G.G. Pereira1; V.C.M. Oliveira1; D.A.R. Moreira2; M.H.M.A. Larsson1
Dilated cardiomyopathy (DCM) is one of the most common acquired cardiovascular diseases of dogs. Few studies have been described in dogs with the purpose of determining prognostic indicators for DCM, and predicting prognosis in any given single patient continues to be a challenge. Therefore, the aim of this study was to evaluate survival time, and to find factors influencing prognosis in dogs with DCM.
Fifty dogs with DCM were prospectively evaluated by physical examination, ten-lead electrocardiography, thoracic radiography, 24-hour Holter monitoring, and echocardiography. The animals were followed-up for at least 150 days or until death. Thirteen clinical variables were studied, including left ventricle shortening fraction, and presence of non-sustained ventricular tachycardia on Holter monitoring. Kaplan-Meier method was used for estimating survival curves. Comparisons of Kaplan-Meier curves were made using Log-Rank test. A multivariate analysis based on exponential distribution was performed, and Cox regression method was used in order to determine independent prognostic factors.
The mean and median survival times were, respectively, 347 days and 223 days (range 5 to 1021 days). Probability of survival at six months was 51%, at 1 year was 37%, and at 2 year was 13%. The survival time was significantly longer (p=0.046) in English Cocker Spaniel. Atrial fibrillation (p=0.037), ventricular ectopy on ten-lead electrocardiography (p=0.022), and non-sustained ventricular tachycardia on Holter monitoring (p<0.001) were associated with increased mortality.
Survival time was variable, but the prognosis was usually poor. The presence of non-sustained ventricular tachycardia in Holter monitoring was the most significant prognostic indicator.