An electronically controlled syringe system for connection to a balloon catheter for automatically monitoring, displaying and recording inflation or deflation data. A syringe having a barrel and a plunger is used to apply or to release pressure to the balloon catheter or other balloon member. A transducer housed on the barrel of the syringe senses fluid pressures applied by the syringe. An electromagnetic signal output by the transducer means is input to a controller where the signal is digitally processed so as to derive and record therefrom electronic data representing the magnitude of applied fluid pressure and the length of time that positive fluid pressure is applied, which derived data is automatically displayed and recorded. The deflation of the balloon-type member is similarly processed and recorded. The controller is also programmable to permit input of various control parameters, such as a lesion location identifier, a maximum positive inflation pressure and maximum duration for applying pressure. Input of the various control parameters can be made at either of two redundant switch sets, where one of the switch sets is located on the syringe barrel.