title: Contact Force in Atrial Fibrillation: Role of Atrial Rhythm and Ventricular Contractions: Co-Force Atrial Fibrillation Study.
abstract: BACKGROUND
  In an experimental model, variable and intermittent contact force (CF) resulted in a significant decrease in lesion volume. In humans, variability of CF during pulmonary vein isolation has not been characterized.
  
  
  RESULTS
  In 20 consecutive patients undergoing CF-guided circumferential pulmonary vein isolation, 914 radiofrequency applications (530 in sinus rhythm and 384 in atrial fibrillation) were analyzed. The variability of the 60% CF range (CF(60%)) was 17±9.6 g. Hundred seventy-one (19%) applications were delivered with constant, 717 (78%) with variable, and 26 (3%) with intermittent CF. The mean CF and force-time integral were significantly higher during applications with variable than with intermittent or constant CF. There was no significant difference in CF variability, CF(60%) variability, and force-time integral between applications delivered in sinus rhythm and atrial fibrillation. The main reasons for CF variability were systolo-diastolic heart movement (29%) and respiration (27%). In 10 additional patients, during adenosine-induced atrioventricular block, the minimum CF significantly increased at 19 sites (5.3±4.4 versus 13.4±5.9 g; P<0.001) and at 16 sites intermittent or variable CF became constant. At only 1 site systolo-diastolic movement remained the main reason for variable CF.
  
  
  CONCLUSIONS
  CF during pulmonary vein isolation remains highly variable despite efforts to optimize contact. CF and CF parameters were similar during sinus rhythm and atrial fibrillation. The main reasons for CF variability are systolo-diastolic heart movement and respiration. The systolo-diastolic peaks and nadirs of CF are because of ventricular contractions at the large majority of pulmonary vein isolation sites.
authors.affiliation: From the Cardiology Department, University Hospital of Antwerp, Antwerp, Belgium (A.S., J.S., T.P., W.B., C.V.); Cardiology Department, University Hospital of Geneve, Geneve, Switzerland (D.S., M.N.); and Cardiology Department, ULB Hospital Erasme, Brussels, Belgium (J.S.). andreasarkozy@yahoo.ca.
authors.forename: Andrea
authors.initials: A
authors.lastname: Sarkozy
authors.affiliation: From the Cardiology Department, University Hospital of Antwerp, Antwerp, Belgium (A.S., J.S., T.P., W.B., C.V.); Cardiology Department, University Hospital of Geneve, Geneve, Switzerland (D.S., M.N.); and Cardiology Department, ULB Hospital Erasme, Brussels, Belgium (J.S.).
authors.forename: Dipen
authors.initials: D
authors.lastname: Shah
authors.affiliation: From the Cardiology Department, University Hospital of Antwerp, Antwerp, Belgium (A.S., J.S., T.P., W.B., C.V.); Cardiology Department, University Hospital of Geneve, Geneve, Switzerland (D.S., M.N.); and Cardiology Department, ULB Hospital Erasme, Brussels, Belgium (J.S.).
authors.forename: Johan
authors.initials: J
authors.lastname: Saenen
authors.affiliation: From the Cardiology Department, University Hospital of Antwerp, Antwerp, Belgium (A.S., J.S., T.P., W.B., C.V.); Cardiology Department, University Hospital of Geneve, Geneve, Switzerland (D.S., M.N.); and Cardiology Department, ULB Hospital Erasme, Brussels, Belgium (J.S.).
authors.forename: Juan
authors.initials: J
authors.lastname: Sieira
authors.affiliation: From the Cardiology Department, University Hospital of Antwerp, Antwerp, Belgium (A.S., J.S., T.P., W.B., C.V.); Cardiology Department, University Hospital of Geneve, Geneve, Switzerland (D.S., M.N.); and Cardiology Department, ULB Hospital Erasme, Brussels, Belgium (J.S.).
authors.forename: Thomas
authors.initials: T
authors.lastname: Phlips
authors.affiliation: From the Cardiology Department, University Hospital of Antwerp, Antwerp, Belgium (A.S., J.S., T.P., W.B., C.V.); Cardiology Department, University Hospital of Geneve, Geneve, Switzerland (D.S., M.N.); and Cardiology Department, ULB Hospital Erasme, Brussels, Belgium (J.S.).
authors.forename: Wim
authors.initials: W
authors.lastname: Boris
authors.affiliation: From the Cardiology Department, University Hospital of Antwerp, Antwerp, Belgium (A.S., J.S., T.P., W.B., C.V.); Cardiology Department, University Hospital of Geneve, Geneve, Switzerland (D.S., M.N.); and Cardiology Department, ULB Hospital Erasme, Brussels, Belgium (J.S.).
authors.forename: Mehdi
authors.initials: M
authors.lastname: Namdar
authors.affiliation: From the Cardiology Department, University Hospital of Antwerp, Antwerp, Belgium (A.S., J.S., T.P., W.B., C.V.); Cardiology Department, University Hospital of Geneve, Geneve, Switzerland (D.S., M.N.); and Cardiology Department, ULB Hospital Erasme, Brussels, Belgium (J.S.).
authors.forename: Christiaan
authors.initials: C
authors.lastname: Vrints
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D016275:Atrial Function; D062906:Cardiac Catheters; D017115:Catheter Ablation / Q000009:adverse effects / Q000295:instrumentation*; D022062:Electrophysiologic Techniques, Cardiac; D004867:Equipment Design; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D011667:Pulmonary Veins / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D014160:Transducers, Pressure; D016896:Treatment Outcome; D016276:Ventricular Function
keywords: atrial fibrillation; catheter ablation; heart; pulmonary veins; respiration