title: Interlead anatomic and electrical distance predict outcome in CRT patients.
abstract: BACKGROUND
  The implantation strategy appears to play a pivotal role in determining response to cardiac resynchronization therapy (CRT).
  
  
  OBJECTIVE
  The aim of our study was to determine the association between anatomic and electrical interlead distance and clinical outcome after CRT implantation.
  
  
  METHODS
  We included 216 first-time CRT recipients with left bundle branch block and sinus rhythm. On implantation, the electrical interlead distance (EID), defined as the time interval between spontaneous peak R waves detected at the right ventricular (RV) and left ventricular (LV) pacing sites, was measured. The anatomic distance between the RV and LV lead tips was determined on chest radiographs.
  
  
  RESULTS
  The mean EID was 74 ± 41 ms, and the mean horizontal corrected interlead distance (HCID) was 125 ± 73 mm. After 12 months, 87 patients (40%) displayed an improvement in their clinical composite score. The cutoff values that best predicted an improved clinical status were as follows: 84 ms for EID (area under the curve 0.59; confidence interval [CI] 0.52-0.66; P = .026) and 90 mm for HCID (area under the curve 0.62; CI 0.55-0.69; P = .004). On multivariate analysis, only EID >84 ms (hazard ratio 0.36; CI 0.14-0.89; P = .028) and HCID >90 mm (hazard ratio 0.45; CI 0.23-0.90; P = .025) were significantly associated with the composite endpoint of death or cardiovascular hospitalization. In particular, the presence of both conditions (EID <84 ms and HCID <90 mm) was associated with the highest rate of events (log-rank test P = .002).
  
  
  CONCLUSIONS
  The interlead anatomic and electrical distance are strongly and independently associated with patient outcome after CRT implantation. The 2 measures show an additive predictive value. (CRT MORE: Cardiac Resynchronization Therapy Modular Registry; www.clinicaltrials.gov, unique identifier: NCT01573091.)
authors.affiliation: Clinica Mediterranea, Napoli, Italy. Electronic address: gmrstabile@tin.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Stabile
authors.affiliation: Ospedale Monaldi, Napoli, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: D'Onofrio
authors.affiliation: Ospedale Carlo Poma, Mantova, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Pepi
authors.affiliation: Clinica San Michele, Maddaloni, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: De Simone
authors.affiliation: Fondazione di Ricerca e Cura 'iovanni Paolo II, Università Cattolica del Sacro Cuore, Campobasso, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Santamaria
authors.affiliation: Ospedale Sant'Antonio Abate, Gallarate (VA), Italy.
authors.forename: Salvatore Ivan
authors.initials: SI
authors.lastname: Caico
authors.affiliation: Departments of Advanced Biomedical Sciences, Federico II University of Naples, Naples, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Rapacciuolo
authors.affiliation: Ospedale Careggi, Università di Firenze, Firenze, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Padeletti
authors.affiliation: Ospedale Poliambulanza, Brescia, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Pecora
authors.affiliation: Ospedale Misericordia e Dolce, Prato, Italy.
authors.forename: Tiziana
authors.initials: T
authors.lastname: Giovannini
authors.affiliation: Ospedale SS Giacomo e Cristoforo, Massa, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Arena
authors.affiliation: Istituti Ospitalieri, Cremona, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Spotti
authors.affiliation: Clinica Mediterranea, Napoli, Italy.
authors.forename: Assunta
authors.initials: A
authors.lastname: Iuliano
authors.affiliation: Dipartimento di Scienze Cardiache, Toraciche e Vascolari, Azienda Ospedaliera di Padova, Padova, Italy.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Bertaglia
authors.affiliation: Boston Scientific Italia, Milano, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Malacrida
authors.affiliation: Ospedale S'Anna, San Fermo della Battaglia (CO), Italy.
authors.forename: Giovanni Luca
authors.initials: GL
authors.lastname: Botto
mesh_terms: D002037:Bundle-Branch Block / Q000175:diagnosis* / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D015331:Cohort Studies; D004562:Electrocardiography / Q000379:methods; D004567:Electrodes, Implanted; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000175:diagnosis / Q000628:therapy; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D013902:Radiography, Thoracic; D020127:Recovery of Function; D012042:Registries; D018570:Risk Assessment; D018709:Statistics, Nonparametric; D013997:Time Factors; D016896:Treatment Outcome
keywords: Cardiac resynchronization therapy; Heart failure; Interlead distance; Interventricular delay; Left bundle brunch block