An impeller (1) for a centrifugal implantable ventricular assist pump comprises a body, blades (3) and closed interblade flow channels (2) with variable cross-sections. The blades (3) of the impeller (1) are of variable thickness. Each channel (2) along the entire length thereof is arch-shaped. The inflow angle (±) onto the blade at the inlet of the channel (2) ranges between 18° and 25°. The outflow angle (²) from the blade (3) at the outlet of the channel (2) does not exceed 30°. The cross-sections (10) of the channel along the entire length thereof from the inlet to the outlet are uniform in shape, and the width (s) and height (h) of the channel (2) along the entire length thereof from the inlet to the outlet increase continuously. The ratio of the width (s) to the height (h) of the channel (2) along the entire length thereof from the inlet to the outlet increases continuously, and the hydraulic radius of the channel (2) along the entire length thereof from the inlet to the outlet increases continuously.
