An ablation therapy system is disclosed comprising an ablation catheter system for treating atrial fibrillation (AF). The ablation catheter system comprises a catheter body including a lumen for receiving a visualization catheter, an ablation element for ablating tissue in a patient's heart having abnormal electrical activity, a support assembly for supporting the ablation element, the support assembly being supported by the catheter assembly. The support assembly includes a lumen to receive the visualization catheter, wherein the support assembly is configured to rotate and/or pivot with respect to the catheter body.