An electrophysiology system, comprising: a catheter including: a flexible catheter body having a distal portion ; and a plurality of electrodes disposed on the distal portion , the plurality of electrodes including: a radiofrequency (RF) ablation electrode ; first, second and third mapping electrodes positioned within the RF ablation electrode; and a plurality of ring electrodes located proximally of the RF ablation electrode and including a first ring electrode located proximally to a distal end of the catheter , an intermediate second ring electrode positioned distally of the first ring electrode , and a distal ring electrode located distally of the second ring electrode ; a signal generator configured to generate an electrical signal by driving one or more currents between a first set of the plurality of electrodes defined by the RF ablation electrode and the first ring electrode , wherein a second set of the plurality of electrodes defined by one of the mapping electrodes and the distal ring electrode is configured to obtain an impedance measurement based on the electrical signal; and a mapping processor configured to: receive the impedance measurement from the second set of electrodes; determine at least one impedance metric; and determine at least one lesion characteristic based on the at least one impedance metric. a catheter including: a flexible catheter body having a distal portion ; and a plurality of electrodes disposed on the distal portion , the plurality of electrodes including: a radiofrequency (RF) ablation electrode ; first, second and third mapping electrodes positioned within the RF ablation electrode; and a plurality of ring electrodes located proximally of the RF ablation electrode and including a first ring electrode located proximally to a distal end of the catheter , an intermediate second ring electrode positioned distally of the first ring electrode , and a distal ring electrode located distally of the second ring electrode ; a flexible catheter body having a distal portion ; and a plurality of electrodes disposed on the distal portion , the plurality of electrodes including: a radiofrequency (RF) ablation electrode ; first, second and third mapping electrodes positioned within the RF ablation electrode; and a plurality of ring electrodes located proximally of the RF ablation electrode and including a first ring electrode located proximally to a distal end of the catheter , an intermediate second ring electrode positioned distally of the first ring electrode , and a distal ring electrode located distally of the second ring electrode ; a signal generator configured to generate an electrical signal by driving one or more currents between a first set of the plurality of electrodes defined by the RF ablation electrode and the first ring electrode , wherein a second set of the plurality of electrodes defined by one of the mapping electrodes and the distal ring electrode is configured to obtain an impedance measurement based on the electrical signal; and a mapping processor configured to: receive the impedance measurement from the second set of electrodes; determine at least one impedance metric; and determine at least one lesion characteristic based on the at least one impedance metric. receive the impedance measurement from the second set of electrodes; determine at least one impedance metric; and determine at least one lesion characteristic based on the at least one impedance metric. <EOS>