A pod propulsion system comprises a housing defining a fluid duct and an annular drum rotatably mounted to the housing within the fluid duct. Each individual VLED may emit light bidirectionally. According to the invention, the actuator is configured as a piston that can be displaced axially between an open and a closed position and the cross-sections of the connection channel and the piston taper from the exterior to the interior in the vicinity of the connection orifices. Additionally, the implanted apparatus may initiate therapy of MII and emerging infarction.