A catheter apparatus for assessing denervation comprises: an elongated catheter body; a deployable structure coupled to the catheter body, the deployable structure being deployable outwardly from and contractible inwardly toward the longitudinal axis of the catheter body; one or more ablation elements disposed on the deployable structure to move outwardly and inwardly with the deployable structure; one or more stimulation elements spaced from each other and disposed on the deployable structure to move with the deployable structure, the stimulation elements being powered to supply nerve stimulating signals to the vessel; and one or more recording elements spaced from each other and from the stimulation elements, the recording elements being disposed on the deployable structure to move with the deployable structure, the recording elements configured to record response of the vessel to the nerve stimulating signals.