title: Effect of fixed-rate vs. rate-RESPONSIve pacing on exercise capacity in patients with permanent, refractory atrial fibrillation and left ventricular dysfunction treated with atrioventricular junction aBLation and bivEntricular pacing (RESPONSIBLE): a prospective, multicentre, randomized, single-blind study.
abstract: OBJECTIVE
  Atrioventricular junction (AVJ) ablation followed by biventricular pacing is an established strategy for improving symptoms and morbidity in patients with permanent atrial fibrillation (AF), reduced left ventricular ejection fraction (LVEF), and uncontrolled ventricular rate. There is no clear evidence that such patients benefit from rate-responsive (RR) pacing.
  
  
  RESULTS
  This prospective, randomized, single-blind, multicentre study was designed as an intra-patient comparison and enrolled 60 patients (age 69.5 ± 11.8 years, males 63.3%, NYHA 3.0 ± 0.6) with refractory AF and reduced LVEF (mean 32.4 ± 8.3%) treated with AVJ ablation and biventricular pacing. Two 6-minute walking tests (6MWT) were performed 1 week apart: one during VVI 70/min biventricular pacing and the other during VVIR 70-130/min biventricular pacing; patients were randomly and blindly assigned to Group A (n = 29, first 6MWT in VVIR mode) or B (n = 31, first 6MWT in VVI mode). Rate-responsive activation determined an increase of 18.8 ± 24.4 m in the distance walked during the 6MWT (P < 0.001). The increase was similar in both groups (P = 0.571). A >5% increase in the distance walked was observed in 76.7% of patients. The increase in the distance walked was linearly correlated with the increase in heart rate recorded during the 6MWT in the VVIR mode (r = 0.54; P < 0.001).
  
  
  CONCLUSIONS
  In permanent AF patients with uncontrolled rate and reduced LVEF who had undergone AVJ ablation and biventricular pacing, RR pacing yields a significant gain in exercise capacity, which seems to be related to the RR-induced frequency during effort.
authors.affiliation: Cardiology Unit, 'Card. G. Panico' Hospital, Via S. Pio X, 4, 73039 Tricase, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Palmisano
authors.affiliation: Cardiology - Coronary Care Unit, Pugliese-Ciaccio Hospital, Catanzaro, Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Aspromonte
authors.affiliation: Department of Cardiology, Monaldi Hospital, Second University of Naples, Naples, Italy.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Ammendola
authors.affiliation: Division of Cardiology, University of Eastern Piedmont, Maggiore della Carità Hospital, Novara, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Dell'era
authors.affiliation: Institute of Cardiology, University of Bologna, S. Orsola-Malpighi University Hospital, Bologna, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Ziacchi
authors.affiliation: Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital 'Umberto I - Lancisi - Salesi', Ancona, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Guerra
authors.affiliation: Department of Cardiology, San Filippo Neri Hospital, Rome, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Aquilani
authors.affiliation: Cardiology - Coronary Care Unit, Pugliese-Ciaccio Hospital, Catanzaro, Italy.
authors.forename: Giampiero
authors.initials: G
authors.lastname: Maglia
authors.affiliation: Department of Cardiology, Monaldi Hospital, Second University of Naples, Naples, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Del Giorno
authors.affiliation: Division of Cardiology, University of Eastern Piedmont, Maggiore della Carità Hospital, Novara, Italy.
authors.forename: Ailia
authors.initials: A
authors.lastname: Giubertoni
authors.affiliation: Institute of Cardiology, University of Bologna, S. Orsola-Malpighi University Hospital, Bologna, Italy.|Cardiology Department, University of Modena and Reggio Emilia, Policlinico di Modena, Modena, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Boriani
authors.affiliation: Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital 'Umberto I - Lancisi - Salesi', Ancona, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Capucci
authors.affiliation: Department of Cardiology, San Filippo Neri Hospital, Rome, Italy.
authors.forename: Renato
authors.initials: R
authors.lastname: Pietro Ricci
authors.affiliation: Cardiology Unit, 'Card. G. Panico' Hospital, Via S. Pio X, 4, 73039 Tricase, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Accogli
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D001283:Atrioventricular Node / Q000503:physiopathology / Q000601:surgery*; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000379:methods*; D017115:Catheter Ablation / Q000009:adverse effects; D017079:Exercise Tolerance; D005260:Female; D006339:Heart Rate; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D020127:Recovery of Function; D016037:Single-Blind Method; D013318:Stroke Volume; D013997:Time Factors; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D016277:Ventricular Function, Left; D000070857:Walk Test
keywords: Ablate and pace; Atrial fibrillation; Cardiac resynchronization therapy; Rate-responsive