A cardiac ventricular assist device or VAD includes a pumping unit with a variable-volume chamber capable of receiving a mass of blood, and a control unit to control the pumping unit to obtain contraction of the variable-volume chamber, with consequent expulsion of the blood collected in the chamber, and expansion of the variable-volume chamber consequent on the flow of blood into the chamber. A flow line is included, such as a transcutaneous line, for a gaseous flow caused by the contraction and expansion of the variable-volume chamber. A sensor sensitive to the gaseous flow in the flow line generates a flow-meter signal that is indicative of the expulsion and inflow of blood with regard to the variable-volume chamber. The control unit is sensitive to said flow-meter signal and utilises that signal to control the pumping unit, for example to cause the pumping unit to operate in a condition of synchronous counterpulsation with regard to the natural heart, that is with the variable-volume chamber capable of receiving blood from the assisted heart when it is in a systolic phase and the variable-volume chamber that expels the blood collected in the chamber, when the assisted heart is in a diastolic phase.