Objective To observe the effect of irbesartan in treating patients with congestive heart failure.Method Forty_two patients\[male26,female16,average age (61?11) with heart failure \[cardiac function (NYHA) grade Ⅲ15 patients,grade Ⅳ27 patients\], who had unsatisfactory results under conventional digitals,diuretics, vasodilators therapy ,were given irbesartan (angiotensinⅡreceptor antagonist)75～300mg orally once a day for 4～6 weeks. The changes of heart rate (HR),blood pressure(BP),cardiothoracic ratio ,left ventricular end diastolic diameter (LVEDD),left ventricular ejection fraction (LVEF) and cardiac function (NYHA) were observed.Results After 4～6 weeks therapy,HR,BP,cardiothoracic ratio and LVEDD all decreased significantly(P