title: Acute and chronic haemodynamic effects of biventricular pacing and of switching to different pacing modalities in heart failure patients.
abstract: BACKGROUND
  In patients with severe heart failure, sinus rhythm and wide QRS complex biventricular (BiV) pacing leads to clinical and haemodynamic improvement, but the immediate reversibility of these changes is not known.
  
  
  METHODS
  We assessed the acute and medium-term (3-month) haemodynamic effects of BiV pacing and of switching to other pacing modalities in 21 patients with severe heart failure, sinus rhythm and QRS>or=130 ms. Haemodynamic studies were performed: 1) at the time of implantation of a BiV pacing device, during AAI pacing, atrial synchronous right ventricular (RV) pacing, atrial synchronous left ventricular (LV) pacing and atrial synchronous BiV pacing (all at 100 bpm); 2) after 3 months of continuous BiV pacing--with evaluations being made by switching to RV and the other pacing modalities.
  
  
  RESULTS
  At both the acute and medium-term evaluations, BiV pacing provided the greatest improvement in cardiac index. Switching from BiV to RV pacing led to a more marked decrease in the cardiac index at 3 months. No strict correlation was evident between acute and medium-term effects of BiV pacing on cardiac index.
  
  
  CONCLUSIONS
  Cardiac resynchronization by BiV pacing provides acute/medium-term improvements in cardiac index. Sudden, medium-term failure of LV stimulation can lead to an even more pronounced haemodynamic derangement than that inducible by RV pacing at baseline. Acute haemodynamic evaluations do not seem to provide a powerful way for identifying medium-term responders.
authors.affiliation: Institute of Cardiology, University of Bologna, Azienda Ospedaliera S.Orsola-Malpighi, Bologna, Italy. cardio1@med.unibo.it
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Boriani
authors.forename: Davide
authors.initials: D
authors.lastname: Saporito
authors.forename: Mauro
authors.initials: M
authors.lastname: Biffi
authors.forename: Cristian
authors.initials: C
authors.lastname: Martignani
authors.forename: Cinzia
authors.initials: C
authors.lastname: Valzania
authors.forename: Igor
authors.initials: I
authors.lastname: Diemberger
authors.forename: Matteo
authors.initials: M
authors.lastname: Ziacchi
authors.forename: Paolo
authors.initials: P
authors.lastname: Artale
authors.forename: Francesco
authors.initials: F
authors.lastname: Grigioni
authors.forename: Letizia
authors.initials: L
authors.lastname: Bacchi
authors.forename: Salvatore
authors.initials: S
authors.lastname: Specchia
authors.forename: Claudio
authors.initials: C
authors.lastname: Rapezzi
authors.forename: Angelo
authors.initials: A
authors.lastname: Branzi
mesh_terms: D000208:Acute Disease; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D002908:Chronic Disease; D006333:Heart Failure / Q000503:physiopathology* / Q000628:therapy*; D006352:Heart Ventricles / Q000503:physiopathology* / Q000601:surgery; D006439:Hemodynamics; D006801:Humans