Catheters for mapping and/or ablation are disclosed. In one embodiment, the catheter comprises a handle, a flexible shaft, a tip assembly, and a cable. The handle includes an actuator and is attached, at its distal end, to the proximal end of the flexible shaft. The flexible shaft has a longitudinal axis that extends along a length of the shaft. The proximal end of the tip assembly is attached to the distal end of the shaft and includes a fixed bend of approximatley ninety degrees relative to the longitudinal axis of the shaft. The distal end of the tip assembly includes an arcuate curve having a diameter. The arcuate curve is oriented in a plane that is approximatley perpendicular to the longitudinal axis of the shaft. The cable is attached to the actuator and the distal end of the tip assembly, and extends through the shaft. The cable is adapted to change the diameter of the arcuate curve in response to movement of the actuator.