Echocardiographic evaluation of systolic and diastolic parameters of dogs with dilated cardiomyopathy treated with carvedilol

Author(s)

Elaine Cristina Soares

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2006-01-13

Examining board members

Maria Helena Matiko Akao Larsson; James Newton Bizetto Meira de Andrade; Wilson Roberto Fernandes; Silvia Regina Ricci Lucas; Denise Saretta Schwartz

• Advisor: Maria Helena Matiko Akao Larsson

Abstract

Dilated Cardiomyopathy (DCM) is the second more common heart disease in dogs, wherein large and giant breeds, as well as Cockers Spaniels, are predisposed. Such disease has a high mortality rate besides reducing the quality of life of the affected animals. The definitive diagnosis is based upon echocardiography which is characterized by dilation of cardiac chambers, mainly the left ones, and by reduced systolic function. Human medicine studies have reported that the diastolic dysfunction also plays an important role; so, an abnormal transmitral flow pattern, which represents the ventricular diastolic filling, has a great prognostic value in terms of survival and symptoms status (heart failure functional class) The management of DCM traditionally consists of digitalis, diuretics and vasodilators, however, in the late years, some attention has being paid to the importance of the sympathetic nervous system on the pathophysiology of this disorder; being so, β-blockers have been included in the therapy. Many authors have reported that these drugs improve the left ventricle systolic and diastolic function, and so they increase the survival rate and reduce the symptoms progression. Forty-five dogs with idiopathic dilated cardiomyopathy, divided into two groups (A and B), were studied. The group A (n=25) consisted of dogs that were put on the traditional therapy (digitalis, diuretics and vasodilators) and the group B (n=20) included those who were treated with all these drugs plus carvedilol, a third generation β-blocker. The animals went through clinical and echocardiographic assesment before and 3, 13, 26 and 52 weeks after starting the treatment or until death. The variables of systolic and diastolic function were not statistically different between the two groups. The median survival time of the dogs treated with carvedilol was higher, but the difference was not statistically significant. Concerning to the symptoms (heart failure funcional class), dogs who were put on carvedilol had a better progression, as more of them were classified as "mild symptoms" after three months of therapy. In conclusion, despite the beneficial effects of carvedilol on the symptoms, these can not be correlate with the systolic and diastolic functions (AU)