title: Magnitude of QRS duration reduction after biventricular pacing identifies responders to cardiac resynchronization therapy.
abstract: BACKGROUND
  Several studies have investigated the association between native QRS duration (QRSd) or QRS narrowing and response to biventricular pacing. However, their results have been conflicting. The aim of our study was to determine the association between the relative change in QRS narrowing index (QI) and clinical outcome and prognosis in patients who undergo cardiac resynchronization therapy (CRT) implantation.
  
  
  RESULTS
  We included 311 patients in whom a CRT device was implanted in accordance with current guidelines for CRT. On implantation, the native QRS, the QRSd and the QI during CRT were measured. After 6months, 220 (71%) patients showed a 10% reduction in LVESV. The median [25th-75th] QI was 14.3% [7.2-21.4] and was significantly related to reverse remodeling (r=+0.22; 95%CI: 0.11-0.32, p=0.0001). The cut-off value of QI that best predicted LV reverse remodeling after 6months of CRT was 12.5% (sensitivity=63.6%, specificity=57.1%, area under the curve=0.633, p=0.0002). The time to the event death or cardiovascular hospitalization was significantly longer among patients with QI>12.5% (log-rank test, p=0.0155), with a hazard ratio (HR) of 0.3 [95%CI: 0.11-0.78]. In the multivariate regression model adjusted for baseline parameters, a 10% increment in QI (HR=0.61[0.44-0.83], p=0.002) remained significantly associated with CRT response.
  
  
  CONCLUSIONS
  Patients with a larger decrease in QRSd after CRT initiation showed greater echocardiographic reverse remodeling and better outcome from death or cardiovascular hospitalization. QI is an easy-to-measure variable that could be used to predict CRT response at the time of pacing site selection or pacing configuration programming.
authors.affiliation: U.O.C. di Cardiologia, Policlinico Universitario "Paolo Giaccone", Palermo, Italy. Electronic address: giuseppe.coppola@unipa.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Coppola
authors.affiliation: U.O.C. di Cardiologia, Policlinico Universitario "Paolo Giaccone", Palermo, Italy.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Ciaramitaro
authors.affiliation: Clinica Mediterranea, Napoli, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Stabile
authors.affiliation: Department of Cardiology, Monaldi Hospital, AORN Ospedali dei Colli, Napoli, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: DOnofrio
authors.affiliation: Cardiology Unit, 'Card. G. Panico' Hospital, Tricase, (LE), Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Palmisano
authors.affiliation: U.O.C. di Cardiologia, Policlinico Universitario "Paolo Giaccone", Palermo, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Carità
authors.affiliation: Department of Cardiology, Cliniche Gavazzeni, Bergamo, Italy.
authors.forename: Giosuè
authors.initials: G
authors.lastname: Mascioli
authors.affiliation: Fondazione Poliambulanza, Brescia, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Pecora
authors.affiliation: Clinica San Michele, Maddaloni, (CE), Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: De Simone
authors.affiliation: S. Chiara Hospital, Trento, Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Marini
authors.affiliation: Departments of Advanced Biomedical Sciences, Federico II University of Naples, Napoli, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Rapacciuolo
authors.affiliation: S. Giovanni Battista Hospital, Foligno, (PG), Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Savarese
authors.affiliation: Cardiology - Coronary Care Unit, Pugliese-Ciaccio Hospital, Catanzaro, Italy.
authors.forename: Giampiero
authors.initials: G
authors.lastname: Maglia
authors.affiliation: Carlo Poma Hospital, Mantova, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Pepi
authors.affiliation: Cardiovascular Department, IRCCS MultiMedica, Sesto San Giovanni, (MI), Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Padeletti
authors.affiliation: Division of Cardiology, S. Salvatore Hospital, Pesaro, (PU), Italy.
authors.forename: Attilio
authors.initials: A
authors.lastname: Pierantozzi
authors.affiliation: SS Giacomo e Cristoforo Hospital, UOC Cardiologia USL 1, Massa, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Arena
authors.affiliation: Misericordia e Dolce Hospital, Prato, Italy.
authors.forename: Tiziana
authors.initials: T
authors.lastname: Giovannini
authors.affiliation: Sant'Antonio Abate Hospital, Gallarate, (VA), Italy.
authors.forename: Salvatore Ivan
authors.initials: SI
authors.lastname: Caico
authors.affiliation: U.O.C. di Cardiologia, Policlinico Universitario "Paolo Giaccone", Palermo, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Nugara
authors.affiliation: U.O.C. di Cardiologia, Policlinico Universitario "Paolo Giaccone", Palermo, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Ajello
authors.affiliation: Boston Scientific Italia, Milano, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Malacrida
authors.affiliation: U.O.C. di Cardiologia, Policlinico Universitario "Paolo Giaccone", Palermo, Italy.
authors.forename: Egle
authors.initials: E
authors.lastname: Corrado
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods* / Q000401:mortality; D002318:Cardiovascular Diseases / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015996:Survival Rate / Q000639:trends; D020257:Ventricular Remodeling / Q000502:physiology*
keywords: Cardiac resynchronization therapy; ECG; Heart failure; Pacing; Reverse remodeling