A cardioplegic agent delivery system comprises a supply reservoir (40) for a cardioplegic agent carrier fluid, a delivery channel from the supply reservoir (40) to an outlet (48), and a pump (50) to flow the carrier liquid in the delivery channel above a minimum driving pressure. The supply reservoir (40) is configured to hold carrier fluid below the minimum driving pressure. The pump (50) is a centrifugal pump configured to receive carrier fluid from the supply reservoir (40) and to flow the carrier fluid to the outlet (48) at a flow rate and above the minimum driving pressure for the delivery of cardioplegic agent. This allows cardioplegia delivery to be managed better.
