title: Assessment of response criteria to cardiac resynchronization therapy (CRT) and prediction of response.
abstract: OBJECTIVE
  Approximately 30% of patients treated with cardiac resynchronization therapy (CRT) do not respond. We evaluated response to CRT at six and 12 months, tested a novel response criterion and evaluated different clinical and echocardiographic predictors of response.
  
  
  RESULTS
  Eighty one patients were enrolled. A definition of response to CRT was predefined as a combination of 1) a reduction of LV end-systolic volume of ≥10% and 2) either an improvement in NYHA class by ≥1 or an increase in peak oxygen consumption of ≥1 ml/kg/min. Pre-and postoperatively at six and 12 months we also evaluated the most commonly employed definitions of response in our material: NYHA class, quality of life, left ventricular (LV) performance and functional capacity. After six and 12 months of CRT, 42 (52%) and 48 patients (59%) were responders, respectively. Employing different criteria, response ranged from 33-96% and 31-94% at six and 12 months, respectively. In our material a large pre-operative interventricular motion delay (IVMD) was a predictor of response to CRT (p<0.05).
  
  
  CONCLUSIONS
  Fifty two percent and 59% were responders to CRT at six months and one year given a predefined novel endpoint. Different response criteria to CRT gave response rates ranging from 33-96% and 31-94% at six and 12 months, respectively. A large IVMD predicts response to CRT at six and 12 months.
authors.affiliation: University of Oslo and Oslo University Hospital, Department of Cardiology, Oslo, Norway. marit.aaronaes@oslo-universitetssykehus.no
authors.forename: Marit
authors.initials: M
authors.lastname: Aarønæs
authors.forename: Svend
authors.initials: S
authors.lastname: Aakhus
authors.forename: Halfdan
authors.initials: H
authors.lastname: Aass
authors.forename: Torbjørn
authors.initials: T
authors.lastname: Moum
authors.forename: Ragnhild
authors.initials: R
authors.lastname: Wergeland
authors.forename: Lars
authors.initials: L
authors.lastname: Gullestad
authors.forename: Erik
authors.initials: E
authors.lastname: Kongsgård
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D058406:Cardiac Resynchronization Therapy; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006306:Health Surveys; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D011379:Prognosis; D011446:Prospective Studies; D011788:Quality of Life; D012720:Severity of Illness Index; D013223:Statistics as Topic; D013318:Stroke Volume; D011795:Surveys and Questionnaires; D013599:Systole; D016896:Treatment Outcome; D018608:Ultrasonography, Doppler; D016277:Ventricular Function, Left