Hemodynamic and plasma atrial natriuretic peptide responses to acute digitalis therapy in patients with normal and impaired left ventricular function.

BACKGROUND: Digitalis has a long history in the treatment of heart failure but its effects on cardiac hemodynamics and neurohormonal modulation are not well characterized. AIMS: The purpose of this study was to evaluate the relationship between atrial natriuretic peptide (ANP) and the hemodynamic responses to acute digitalis administration in patients with normal and impaired left ventricular function (LVD). METHODS AND RESULTS: Thirty patients were enrolled in the study, 20 with LVD (LVEF=22+/-8%) and 10 control subjects (LVEF=77+/-10%). Hemodynamics and plasma ANP concentrations were measured supine and with leg elevation before and after digitalis. In patients with normal ventricular function, the hemodynamic stress of leg elevation in the pre-digitalis state resulted in significant (P<0.05) increases in PAWP and MPAP. Digitalis administration in the supine position produced reductions in heart rate, PAWP, MPAP and CI; SVR was increased. In LVD patients leg elevation further increased PAWP, RAP and MPAP. Digitalis in the supine position, however, reduced RAP, MPAP and PAWP and increased CI. These improved hemodynamics were preserved during the stress of leg elevation. Leg elevation following digitalis resulted in increased ANP concentrations despite decreased cardiac filling pressures. CONCLUSIONS: Acute digitalis administration results in hemodynamic improvement in LVD patients which may in part result from digitalis stimulated release of myocardial ANP under conditions of hemodynamic stress.