title: Long-term outcome of 'super-responder' patients to cardiac resynchronization therapy.
abstract: OBJECTIVE
  To evaluate the long-term changes of clinical and echocardiographic parameters, the incidence of cardiac events and parameters associated with late cardiac events in 'super-responders' to cardiac resynchronization therapy (CRT) with [CRT defibrillator (CRT-D)] or without defibrillator back-up.
  
  
  RESULTS
  In all consecutive patients treated with CRT in two Italian centres (Trieste and Udine) with left ventricular ejection fraction (LVEF) ≤0.35 at implantation (Timp) and LVEF > 0.50 1 and/or 2 years (Tnorm) after implantation, the long-term outcome and the evolution of echocardiographic parameters were assessed; factors associated with a higher risk of cardiac events, defined as hospitalization or death for heart failure (HF), sudden death, or CRT-D appropriate interventions, were also analysed. Among the 259 patients evaluated, 62 (24%) had LVEF ≥ 0.50 at Tnorm (n = 44 with at 1 year, n = 18 at 2 years). During a mean follow-up of 68 ± 30 months, one cardiac death (for HF) and eight cardiovascular events (two hospitalization for HF and six appropriate CRT-D interventions) occurred. At the last echo evaluation (Tfup) performed 51 ± 26 months after Timp, LVEF was <0.50 in five patients (>0.45 in four of them). At univariable analysis, only LV end-systolic volume evaluated at Tfup was associated with a higher risk of cardiac events during follow-up.
  
  
  CONCLUSIONS
  In 'super-responders' to CRT long-term outcome is excellent. However, cardiac events, mainly CRT-D appropriate interventions, can occur despite the persistence of LVEF > 0.50. Early identification of these patients is still an unsolved issue.
authors.affiliation: Cardiovascular Department, University and 'Ospedali Riuniti di Trieste' Hospital, Via Valdoni, 7, 34129 Trieste, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Zecchin
authors.forename: Alberto
authors.initials: A
authors.lastname: Proclemer
authors.forename: Silvia
authors.initials: S
authors.lastname: Magnani
authors.forename: Laura
authors.initials: L
authors.lastname: Vitali-Serdoz
authors.forename: Domenico
authors.initials: D
authors.lastname: Facchin
authors.forename: Daniele
authors.initials: D
authors.lastname: Muser
authors.forename: Andrea
authors.initials: A
authors.lastname: Nordio
authors.forename: Giulia
authors.initials: G
authors.lastname: Barbati
authors.forename: Ilaria
authors.initials: I
authors.lastname: Puggia
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Sinagra
authors.forename: Alessandro
authors.initials: A
authors.lastname: Proclemer
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000401:mortality*; D003131:Combined Modality Therapy; D015897:Comorbidity; D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000517:prevention & control; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D005260:Female; D006333:Heart Failure / Q000401:mortality* / Q000517:prevention & control*; D017052:Hospital Mortality; D006801:Humans; D007558:Italy; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D012307:Risk Factors; D016896:Treatment Outcome
keywords: Cardiac resynchronization therapy; Heart failure; Outcome; Super-responders