title: [Predictors of lack of clinical improvement at mid-term follow-up with cardiac resynchronization therapy].
abstract: BACKGROUND
  About 30% of all patients do not respond to cardiac resynchronization therapy for heart failure. The objective of the study was to analyze the variables that may predict the lack of response.
  
  
  METHODS
  We analyzed the results in a series of 63 patients who received cardiac resynchronization with a biventricular device. Clinical and left ventricular function parameters were evaluated at the beginning of the study and at 6 months. Responders were defined as those who were alive, had not received a heart transplant, and who achieved more than a 10% increase in distance in the 6-minute walking test.
  
  
  RESULTS
  Mean age was 68.3 (8) years, 51 patients (81%) were men, and NYHA functional class was III-IV in 79.4%. Mean left ventricular ejection fraction was 22.4% (6)%, QRS width was 177 (25) ms, and 77.8% were in sinus rhythm. Almost half (46%, n=29) had ischemic heart disease. At 6-month follow-up, 69.8% of the patients were responders. Ischemic heart disease, sustained monomorphic ventricular tachycardia and a degree of mitral regurgitation >II/IV before implantation were associated with lack of response. No association was found for any of the other baseline variables. Logistic regression analysis identified all three of the aforementioned variables as independent predictors of lack of response: ischemic heart disease OR=4.8, 95% CI, 1.2-18.3, P=.023; ventricular tachycardia OR=8.7, 95% CI, 1.8-41.3, P=.007; and mitral regurgitation OR=8.03, 95% CI, 1.7-37.1, P=.008.
  
  
  CONCLUSIONS
  The likelihood of responding to resynchronization therapy is lower in patients with ischemic heart disease, significant mitral regurgitation, or sustained monomorphic ventricular tachycardia.
authors.affiliation: Unidad de Arritmias, Instituto de Enfermedades Cardiovasculares, Hospital Clínico Universitario, Universidad de Barcelona, Barcelona, España.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Díaz-Infante
authors.forename: Antonio
authors.initials: A
authors.lastname: Berruezo
authors.forename: Lluís
authors.initials: L
authors.lastname: Mont
authors.forename: Paulo
authors.initials: P
authors.lastname: Osorio
authors.forename: Emilio
authors.initials: E
authors.lastname: García-Morán
authors.forename: Alba
authors.initials: A
authors.lastname: Marigliano
authors.forename: Marta
authors.initials: M
authors.lastname: Sitges
authors.forename: Manel
authors.initials: M
authors.lastname: Azqueta
authors.forename: Carles
authors.initials: C
authors.lastname: Paré
authors.forename: Africa
authors.initials: A
authors.lastname: Muxí
authors.forename: Pilar
authors.initials: P
authors.lastname: Paredes
authors.forename: Xavier
authors.initials: X
authors.lastname: Fosch
authors.forename: Salvador
authors.initials: S
authors.lastname: Ninot
authors.forename: Eulalia
authors.initials: E
authors.lastname: Roig
authors.forename: Josep
authors.initials: J
authors.lastname: Brugada
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000628:therapy; D006801:Humans; D008297:Male; D011379:Prognosis; D011446:Prospective Studies; D013997:Time Factors; D017211:Treatment Failure