title: Long-term clinical response to cardiac resynchronisation therapy under a multidisciplinary model.
abstract: BACKGROUND
  Cardiac resynchronisation therapy (CRT) is established in the management of cardiac failure in patients with systolic dysfunction. Clinical response to CRT is not uniform, and response has been difficult to predict.
  
  
  OBJECTIVE
  Patient management within a high volume, multidisciplinary service focused on optimal delivery of CRT would improve response rates.
  
  
  METHODS
  Four hundred and thirty-five consecutive patients who underwent CRT under a multidisciplinary heart failure service were enrolled prospectively over a 5-year period. Medically optimised, symptomatic patients with an ejection fraction (EF) <35%, widened QRS or abnormal dyssynchrony index were included. Left ventricular lead position was targeted anatomically to the segment of latest mechanical activation, and electrically to a site with maximal intrinsic intracardiac electrogram separation. Routine device and clinical follow up, as well as CRT optimisations, were performed at baseline and at 3-monthly intervals. Responders were defined as having an absolute reduction in left ventricular end-diastolic diameter >10% and an improvement in EF >5%.
  
  
  RESULTS
  With a mean follow up of 53 ± 11 months, response rate to CRT was 81%. Mean EF improved from 26 ± 10% to 37 ± 11%, and mean left ventricular end-diastolic diameter reduced from 68.6 ± 9.2 mm to 57.8 ± 9.3 mm. Predictors of response were sinus rhythm, high dyssynchrony index and intrinsic electrical dyssynchrony >80 ms. Successful LV lead implantation at initial procedure was achieved in 99.1%, and at latest follow up 94.6% of initial LV leads were still active.
  
  
  CONCLUSIONS
  CRT undertaken with a unit focus on optimal LV lead positioning and device optimisation, along with a multidisciplinary follow-up model, results in an excellent response rate to CRT.
authors.affiliation: Department of Cardiology, Austin Health, Melbourne, Victoria, Australia.
authors.forename: D
authors.initials: D
authors.lastname: O'Donnell
authors.forename: T
authors.initials: T
authors.lastname: Lin
authors.forename: M
authors.initials: M
authors.lastname: Swale
authors.forename: P
authors.initials: P
authors.lastname: Rae
authors.forename: D
authors.initials: D
authors.lastname: Flannery
authors.forename: P M
authors.initials: PM
authors.lastname: Srivastava
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000639:trends*; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D011446:Prospective Studies; D013318:Stroke Volume / Q000502:physiology; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology
keywords: cardiac resynchronisation therapy; defibrillator; dyssynchrony; left ventricular lead position; long-term response