Left ventricular ejection force as been purpose as a new Doppler ejection phase index, to assess left ventricular performance. In order to evaluate its usefulness, 33 patients undergoing cardiac catheterization were prospectively study. We considered three groups based on angiographic ejection fraction: group A-- > or = 55% (11 patients), group B--35 to 55% (10 patients), and group C-- < or = 35% (10 patients). All patients were in sinus rhythm and mitral regurgitation > I/IV or aortic valve disease were exclusion criterion. The following parameters, derived from Pulsed Doppler aortic velocities curves, were analyzed: peak velocity (cm/s), acceleration time (s), velocity time integral over the acceleration time (VTI Ac-cm), mean acceleration (cm/s2) and ejection force (g.cm/s2). Ejection force as calculated using the mass-acceleration concept, ad: ejection force = mean acceleration x VTI Ac x CsA x 1.06 (CsA - 2D cross sectional area of the aortic annulus; 1.06 - mass density of blood, g/cm3). [table: see text] CONCLUSIONS The present study confirms that Doppler echocardiography can be used for the assessment of left ventricular performance based on noninvasive measurements and that Doppler derived ejection force is an accurate index for this purpose. However, ejection force evaluation, taking in account the results obtained for mean acceleration, a much less time consuming Doppler derived parameter, appears not to show any clinical advantage.