Pulsative ventricular assist device

A ventricular assist device (VAD) for use with a heart, comprising:

• a housing;
• an upper membrane pump comprising a pumping chamber coupled to one-way upper inlet and outlet valves, said pumping chamber having a volume between an upper portion of said housing and a membrane sealed to said housing, and an upper piston rod, an upper end of which is arranged to cause movement of said membrane of said upper membrane pump;
• a lower membrane pump comprising a pumping chamber coupled to one-way lower inlet and outlet valves, said pumping chamber having a volume between a lower portion of said housing and a membrane sealed to said housing, and a lower piston rod, a lower end of which is arranged to cause movement of said membrane of said lower membrane pump;
• and
• an actuator coupled to said upper piston rod and to said lower piston rod and configured to cause reciprocating motion of said upper piston rod and said lower piston rod to cause said upper membrane pump and said lower membrane pump to alternately draw blood into and pump blood out of their respective pumping chambers, and a control module in operative communication with said actuator, wherein said actuator operates with a pumping frequency which is greater than a pulse frequency of the heart.