title: Could it be advantageous to tune the temperature controller during radiofrequency ablation? A feasibility study using theoretical models.
abstract: OBJECTIVE
  To assess whether tailoring the Kp and Ki values of a proportional-integral (PI) controller during radiofrequency (RF) cardiac ablation could be advantageous from the point of view of the dynamic behaviour of the controller, in particular, whether control action could be speeded up and larger lesions obtained.
  
  
  METHODS
  Theoretical models were built and solved by the finite element method. RF cardiac ablations were simulated with temperature controlled at 55°C. Specific PI controllers were implemented with Kp and Ki parameters adapted to cases with different tissue values (specific heat, thermal conductivity and electrical conductivity) electrode-tissue contact characteristics (insertion depth, cooling effect of circulating blood) and electrode characteristics (size, location and arrangement of the temperature sensor in the electrode).
  
  
  RESULTS
  The lesion dimensions and T(max) remained almost unchanged when the specific PI controller was used instead of one tuned for the standard case: T(max) varied less than 1.9°C, lesion width less than 0.2 mm, and lesion depth less than 0.3 mm. As expected, we did observe a direct logical relationship between the response time of each controller and the transient value of electrode temperature.
  
  
  CONCLUSIONS
  The results suggest that a PI controller designed for a standard case (such as that described in this study), could offer benefits under different tissue conditions, electrode-tissue contact, and electrode characteristics.
authors.affiliation: Biomedical Synergy, Electronic Engineering Department, Universtat Politècnica de València, Spain.
authors.forename: José
authors.initials: J
authors.lastname: Alba-Martínez
authors.forename: Macarena
authors.initials: M
authors.lastname: Trujillo
authors.forename: Ramón
authors.initials: R
authors.lastname: Blasco-Giménez
authors.forename: Enrique
authors.initials: E
authors.lastname: Berjano
mesh_terms: D006348:Cardiac Surgical Procedures / Q000379:methods*; D017115:Catheter Ablation / Q000379:methods*; D004553:Electric Conductivity; D004566:Electrodes; D005240:Feasibility Studies; D020342:Finite Element Analysis; D006321:Heart; D008962:Models, Theoretical; D013696:Temperature; D013814:Thermal Conductivity