A medical device for use by an operator to perform a medical procedure in a body includes a handle to be held by the operator, a shaft attached to the handle and an actuating assembly to control functions associated with the medical procedure. The shaft includes an operative distal portion to perform a medical procedure in the body. The medical device may be part of an ablation catheter system that is programmed to correlate one or more functions with the actuation of the actuating assembly. Multiple actuating assemblies may be provided. Each actuating assembly may be a button. Other types of actuating assemblies may also be used, such as switches or a trackball. The actuating assembly may also be provided on a sleeve that may be selectively attached to the handle of the catheter or the physician operating the catheter, for example.