[Treatment of mitral valve insufficiency in dogs with the ACE inhibitor enalapril. A clinical progress study].

The efficacy and safety of the angiotensin converting enzyme inhibitor enalapril in dogs with naturally acquired class III or class IV heart failure was evaluated in this study. Eighteen small-breed dogs with insufficiency of their mitral valves, but without other diseases were included in this study over a period of six months. When necessary due to massive pulmonary edema or high serum potassium concentrations, furosemide was added to the therapy with enalapril. No other drugs, including digitalis, were used in this study. The treatment was followed by anamnesis, clinical examinations, electrocardiography, radiography, echocardiography and laboratory diagnosis. Examinations were performed before treatment and after one week, after six weeks and after six months of treatment. 72% of the dogs improved in NYHA classification until the end of the study (p < 0.05). The incidence of seizures due to syncopes or severe respiratory distress decreased during this study (p < 0.01). For 28% of the dogs this treatment was not successful. In the electrocardiographic, radiographic and laboratory examinations statistically significant changes could not be recorded. The decrease in heart rate did not reach statistical significance. The echocardiographic investigation evaluated a significant decrease in fractional shortening and in the diastolic diameter of the left ventricular wall (p < 0.05 respectively p < 0.01), but no significant change in the diastolic or systolic diameter of the interventricular septum. The average oral dose of enalapril was 0.38 mg/kg body weight b.i.d., the average dose of furosemide was 0.37 mg/kg body weight b.i.d. in the first week of the study and was raised to 0.74 mg/kg body weight b.i.d. until the end of the study. Side effects like diarrhea, vomiting or reduced appetite did not increase during the course of the study. However one dog was excluded from the study because of repeated vomiting after six weeks of treatment. This study shows the beneficial clinical and hemodynamic effects and the security of the therapy with enalapril for dogs with heart failure due to mitral insufficiency.