title: Quantitative magnetic resonance imaging analysis of the relationship between contact force and left atrial scar formation after catheter ablation of atrial fibrillation.
abstract: BACKGROUND
  Catheter contact force (CF) is an important determinant of radiofrequency (RF) lesion quality during pulmonary vein isolation (PVI). Late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) allows good visualization of ablation lesions.
  
  
  OBJECTIVE
  This study describes a new technique to examine the relationship between CF during RF delivery and LGE signal intensity (SI) following PVI.
  
  
  METHODS
  Six patients underwent PVI for paroxysmal AF using a CF-sensing catheter and following preprocedural MRI. During ablation, CF-time integral (FTI) and position was documented for each RF application. All patients underwent repeat LGE MRI 3 months later. The LGE SIs were projected onto a MRI-derived 3-dimensional left atrial (LA) shell and a CF map was generated on the same shell. The entire LA surface was divided into 5 mm(2) segments. Force and LGE maps were fused and compared for each 5 mm(2) zone. An effective lesion was defined when MRI-defined scar occupied >90% of a 5 mm(2) analysis zone.
  
  
  RESULTS
  Acute PVI was achieved in 100%. Two hundred sixty-eight RF lesions were tagged on the LA shells and given a lesion-specific FTI. Increasing FTI correlated with increased LGE SI, which was greater when the FTI was > 1,200 gs. Below an FTI of 1,200 gs, an increment in the FTI resulted in only a small increment in scar, whereas above 1,200 gs an increment in the FTI resulted in a large change of scar.
  
  
  CONCLUSIONS
  There is a correlation between FTI and LGE SI in MRI following AF ablation. Real-time FTI maps are feasible and may prevent inadequate lesion formation.
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, King's College London, London, UK; Department of Cardiology and Pneumology, Heart Center, Georg-August-University of Göttingen, Göttingen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Sohns
authors.forename: Rashed
authors.initials: R
authors.lastname: Karim
authors.forename: James
authors.initials: J
authors.lastname: Harrison
authors.forename: Aruna
authors.initials: A
authors.lastname: Arujuna
authors.forename: Nick
authors.initials: N
authors.lastname: Linton
authors.forename: Richard
authors.initials: R
authors.lastname: Sennett
authors.forename: Hendrik
authors.initials: H
authors.lastname: Lambert
authors.forename: Giovanni
authors.initials: G
authors.lastname: Leo
authors.forename: Steven
authors.initials: S
authors.lastname: Williams
authors.forename: Reza
authors.initials: R
authors.lastname: Razavi
authors.forename: Matt
authors.initials: M
authors.lastname: Wright
authors.forename: Tobias
authors.initials: T
authors.lastname: Schaeffter
authors.forename: Mark
authors.initials: M
authors.lastname: O'Neill
authors.forename: Kawal
authors.initials: K
authors.lastname: Rhode
mesh_terms: D001281:Atrial Fibrillation / Q000473:pathology* / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D002921:Cicatrix / Q000209:etiology* / Q000473:pathology* / Q000503:physiopathology; D003199:Computer Systems; D005260:Female; D006325:Heart Atria / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011667:Pulmonary Veins / Q000473:pathology / Q000601:surgery; D013314:Stress, Mechanical; D016896:Treatment Outcome
keywords: atrial fibrillation; catheter ablation; contact force; left atrium; magnetic resonance imaging; pulmonary vein isolation