The present disclosure provides an improved ablation catheter. In particular, the present disclosure provides an improved renal denervation ablation catheter and system including a catheter handle and a means for tracking, monitoring, and/or recording the circumferential angular history of the renal denervation ablation catheter handle. The renal denervation ablation catheters in accordance with the present disclosure are well-suited for use with a renal denervation ablation system that can record the circumferential angular history of the renal denervation catheter handle, and hence the circumferential angular ablation history of the catheter electrode within a vessel, and use this data in combination with other known information to estimate the percent circumferential denervation of the vessel.