title: Persistent improvement of ejection fraction in patients with a cardiac resynchronisation therapy defibrillator correlates with fewer appropriate ICD interventions and lower mortality.
abstract: OBJECTIVE
  Cardiac resynchronisation therapy with defibrillator back-up (CRT-D) is a well-established treatment option for selected heart failure patients. Left ventricular ejection fraction (LVEF), an important risk determinant of life-threatening arrhythmias, can substantially ameliorate with CRT. Our hypothesis was that patients with LVEF improvement to >40% have a lower arrhythmic risk and fewer appropriate defibrillator therapies beyond year one.
  
  
  METHODS
  In this retrospective analysis, all 175 patients with CRT-D implanted from February 2000 to June 2011 and follow-up of >2 years were identified. Every available echocardiography recording was collected. LVEF measurements were grouped to baseline and yearly intervals (±6 months). All appropriate defibrillator therapies were considered events.
  
  
  RESULTS
  Age at implant was 65 ± 10 years, 86% were male, and 45% patients had ischemic cardiomyopathy. Follow-up was 5.5 ± 2.6 years. LVEF at implant was 25 ± 6%, increased to 34 ± 12% after one year and remained stable thereafter. 39% (69) of patients experienced a sustained increase of LVEF to ≥40%, 14% of them had tachyarrhythmic events (versus 42.5% in those without such increase). Independent predictors for increase were higher baseline LVEF (HR 1.08 (95%-CI 1.04-1.28) per 1% increase) and lack of amiodarone (HR 0.37, 95%-CI 0.16-0.84). With cut-off values of >40%, >45% and >50%, the study hypothesis was refuted in 7%, 2.5% and 5%, respectively. Cumulative 5-year survival was 95% in improvers versus 73% in non-improvers (p <0.001).
  
  
  CONCLUSIONS
  After CRT-D implantation, mean LVEF increased to >40% in 1/3 of patients. These patients experienced significantly fewer arrhythmias during long-term follow-up when compared to patients with persisting LVEF <40%.
authors.affiliation: Department of Cardiology, University Hospital of Basel, Switzerland.
authors.forename: Beat
authors.initials: B
authors.lastname: Schaer
authors.affiliation: Department of Cardiology, University Hospital of Basel, Switzerland.
authors.forename: Simon
authors.initials: S
authors.lastname: Frey
authors.affiliation: Department of Cardiology, University Hospital of Basel, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Sticherling
authors.forename: Stefan
authors.initials: S
authors.lastname: Osswald
authors.affiliation: Department of Cardiology, University Hospital of Basel, Switzerland.
authors.forename: Tobias
authors.initials: T
authors.lastname: Reichlin
authors.affiliation: Department of Cardiology, University Hospital of Basel, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Kühne
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000453:epidemiology* / Q000503:physiopathology; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D058409:Cardiac Resynchronization Therapy Devices; D017147:Defibrillators, Implantable; D018450:Disease Progression; D005260:Female; D006333:Heart Failure / Q000209:etiology / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009026:Mortality; D017202:Myocardial Ischemia / Q000150:complications; D012189:Retrospective Studies; D013318:Stroke Volume; D016896:Treatment Outcome