A catheter that is particularly useful for mapping electrical activity in the heart of a patient is provided. The catheter comprises an elongated catheter body having a lumen extending longitudinally therethrough. A control handle is attached to the proximal end of the catheter body and includes first and second members that are moveable relative to each other. The second member is attached to the catheter body. An inner member is slidably mounted in the lumen of the catheter body. The inner member comprises an elongated stiffening member that is surrounded by and connected to a non-conductive covering having a free distal end on which is mounted one or more electrodes. The proximal end of the inner member is attached to the first member of the control handle. Longitudinal movement of the first member relative to the second member results in longitudinal movement of the inner member relative to the catheter body to cause the inner member to extend out of and retract into the catheter body.