Echocardiographic determination of left ventricular haemodynamics following acute and chronic administration of frusemide (Lasix) to patients with heart failure.

Twenty patients (8 females) with NYHA class II symptoms of chronic left ventricular heart failure completed a study to investigate the hemodynamic effects of intravenous and oral frusemide. Echocardiography indicated that frusemide 20 mg intravenously produces a transient undesired hemodynamic effect in the prediuretic phase without any influence on the patient's clinical symptoms. Once diuresis is established the hemodynamic conditions are reversed and there is an improvement in cardiac function. There is no evidence of a direct positive inotropic effect of the drug. Repeated oral dosing with frusemide 40 mg/day for 3 weeks produced an improvement in cardiac hemodynamics particularly during the first 2 weeks of treatment. The possible underlying mechanisms for these observations are discussed.