title: Application of microwave energy in cardiac tissue ablation: from in vitro analyses to clinical use.
abstract: BACKGROUND
  Recently, there has been renewed interest in simplifying a surgical cure for atrial fibrillation. Microwave energy ablation provides an easier and faster surgical technique, in lieu of traditional "cut and sew," which can also be applied on the beating heart.
  
  
  METHODS
  Specific absorption rate (SAR) and thermal profiles were determined after microwave energy ablation intended for clinical application. Lesion geometry measures obtained in vitro with tissue equivalent media were compared with values collected from animal myocardium.
  
  
  RESULTS
  Thermal profile analysis demonstrated lesion penetration depths of 2.5, 3, and 5 mm after 8, 16, and 24 seconds, respectively, with microwave power application of 40 W. Dosimetric studies performed using animal myocardium corresponded to the thermal profile analysis and showed that lesion depth was controlled by the output power and the ablation time.
  
  
  CONCLUSIONS
  Lesion geometry in tissue using microwave energy is similar to that predicted from in vitro analysis. The ablation depths and thermal profile of microwave ablation is favorable for performing atrial ablation, and this is corroborated by favorable early clinical results.
authors.affiliation: Columbia University, New York Presbyterian Hospital, New York, New York, USA. mw365@columbia.edu
authors.forename: Mathew R
authors.initials: MR
authors.lastname: Williams
authors.forename: Michael
authors.initials: M
authors.lastname: Knaut
authors.forename: Dany
authors.initials: D
authors.lastname: Bérubé
authors.forename: Mehmet C
authors.initials: MC
authors.lastname: Oz
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000473:pathology / Q000628:therapy*; D004867:Equipment Design; D006801:Humans; D006979:Hyperthermia, Induced / Q000295:instrumentation*; D066298:In Vitro Techniques; D008872:Microwaves; D009206:Myocardium / Q000473:pathology; D013696:Temperature