title: Relationship between catheter forces, lesion characteristics, "popping," and char formation: experience with robotic navigation system.
abstract: BACKGROUND
  Popping, char and perforation are complications that can occur following catheter ablation. We measured the amount of grams (g) applied to the endocardium during ablation using a sensor incorporated in the long sheath of a robotic system. We evaluated the relationship between lesion formation, pressure, and the development of complications.
  
  
  METHODS
  Using a robotic navigation system, lesions were placed in the left atrium (LA) at six settings, using a constant duration (40 seconds) and flow rate of either 17 cc/min or 30 cc/min with an open irrigated catheter (OIC). Evidence of complications was noted and lesion location recorded for later analysis at necropsy.
  
  
  RESULTS
  Lesions using 30 Watts (W) were more likely to be transmural at higher (>40 g) than lower (<30 g) pressures (75% vs 25%, P < 0.001). Significantly higher number of lesions using >40 g of pressure demonstrated "popping" and crater formation as compared with lesions with 20-30 g of pressure (41% vs 15%, P = 0.008). A majority of lesions placed using higher power (45 W) with higher pressures (>40 g) were associated with char and crater formation (66.7%). No lesions using 10 g of pressure were transmural, regardless of the power. Lesions placed with a power setting less than 35 W were more likely to result in "relative" sparing of the endocardial surface than lesions at a power setting higher than 35 W (62% vs 33.3%, P = 0.02) regardless of the pressure.
  
  
  CONCLUSIONS
  When using an OIC, lower power settings (<or=35 W) and lower/medium contact pressure were more likely to show a "relative" spared endocardial surface. Overall, contact pressure between 20 g and 30 g and a power setting of 40 W appeared to achieve transmurality by preserving safety.
authors.affiliation: Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Luigi
authors.initials: L
authors.lastname: Di Biase
authors.forename: Andrea
authors.initials: A
authors.lastname: Natale
authors.forename: Conor
authors.initials: C
authors.lastname: Barrett
authors.forename: Carmela
authors.initials: C
authors.lastname: Tan
authors.forename: Claude S
authors.initials: CS
authors.lastname: Elayi
authors.forename: Chi Keong
authors.initials: CK
authors.lastname: Ching
authors.forename: Paul
authors.initials: P
authors.lastname: Wang
authors.forename: Amin
authors.initials: A
authors.lastname: Al-Ahmad
authors.forename: Mauricio
authors.initials: M
authors.lastname: Arruda
authors.forename: J David
authors.initials: JD
authors.lastname: Burkhardt
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Wisnoskey
authors.forename: Punam
authors.initials: P
authors.lastname: Chowdhury
authors.forename: Shari
authors.initials: S
authors.lastname: De Marco
authors.forename: Luciana
authors.initials: L
authors.lastname: Armaganijan
authors.forename: Kenneth N
authors.initials: KN
authors.lastname: Litwak
authors.forename: Robert A
authors.initials: RA
authors.lastname: Schweikert
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Cummings
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000009:adverse effects* / Q000295:instrumentation; D004285:Dogs; D004699:Endocardium / Q000000981:diagnostic imaging / Q000293:injuries*; D004867:Equipment Design; D005260:Female; D006335:Heart Injuries / Q000000981:diagnostic imaging / Q000209:etiology* / Q000517:prevention & control; D008297:Male; D008422:Materials Testing; D011312:Pressure; D018570:Risk Assessment; D012371:Robotics; D013314:Stress, Mechanical; D025321:Surgery, Computer-Assisted; D014463:Ultrasonography