We have developed Doppler mitral pow velocity (mfv) indices to estimate peak atrio-ventricular pressure gradient (pg), it's mean and peak rate of change with time (pag and mag) to assess left atrial contractility. Our indices were measured from the digitised mfv signals which were fitted to splines of polynomials in time to represent mitral inflow during atrial systole in 4 normals (GpA) and 10 patients with stable NYHA grade 3 heart failure (GpS). The means (standard deviations) for pg, pag and mag for GpA versus GpB were 4.04 (1.04)mm Hg, 417 (154) and 211.5 (79.7)mm Hg s(-1) respectively versus 2.39 (1.06)mm Hg, 117(111) and 43.5(34)mm Hg s(-1) respectively. Mean indices pg, pag and mag were significantly greater for GpA, t values at the 95% Confidence interval=2.65, 3.91 and 5.73 respectively and p values= 0.021, 0.003 and 0.0001 respectively.