title: [Biventricular pacing as a treatment for advanced heart failure. Preliminary experience in a series of 22 consecutive patients].
abstract: OBJECTIVE
  Recent data suggest that biventricular pacing may play an important role in treating advanced heart failure in the presence of a significant interventricular and/or intraventricular conduction disorder by correcting cardiac dysynchrony. In this article, we review the initial technical and clinical experience with cardiac resynchronization therapy in an electrophysiology laboratory.
  
  
  METHODS
  The first 22 consecutive patients with severe congestive heart failure, ejection fraction < 0.35, NYHA functional class III or IV, and QRS duration > 120 ms who were implanted biventricular pacemakers were studied. Clinical, electrocardiographic, and echocardiographic evaluations were made before and three months after pacemaker implantation. Acute functional capacity testing with peak oxygen uptake was measured during biventricular pacing and during intrinsic rhythm or right ventricular pacing three months after the implantation procedure.
  
  
  RESULTS
  The success rate of pacemaker implantation was 95%. Pre-discharge left ventricular pacing was achieved in 91%, with an average pacing threshold of 1.53 (1.04) volts. NYHA functional class improved (p = 0.039) from 3.4 (0.7) to 2.3 (0.78). The rate of hospitalization for heart failure decreased from an average of 3.12 (0.58) three months before the procedure to 1.38 (0.34) three months after the procedure. Peak oxygen uptake was significantly greater (p = 0.028) during biventricular pacing: 14.89 (2.1) ml/min/kg, than during intrinsic rhythm or right ventricular pacing: 12.65 (2.3) ml/min/kg.
  
  
  CONCLUSIONS
  Cardiac resynchronization therapy can be performed safely and with a high success rate in the electrophysiology laboratory. Biventricular pacing seems to improve the symptoms of congestive heart failure in patients with evidence of atrioventricular and/or interventricular/intraventricular dysynchrony. An acute benefit in peak oxygen uptake was associated with biventricular pacing after the implantation procedure.
authors.affiliation: Departamento de Cardiología y Cirugía Cardiovascular. Clínica Universitaria de Navarra. Facultad de Medicina. Universidad de Navarra. Pamplona. España. igarciab@unav.es
authors.forename: Ignacio
authors.initials: I
authors.lastname: García-Bolao
authors.forename: Alfonso
authors.initials: A
authors.lastname: Macías
authors.forename: Eduardo
authors.initials: E
authors.lastname: Alegría
authors.forename: Alejandro
authors.initials: A
authors.lastname: Berenguel
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Gavira
authors.forename: Pedro
authors.initials: P
authors.lastname: Azcárate
authors.forename: Joaquín
authors.initials: J
authors.lastname: Barba
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000150:complications / Q000628:therapy*; D006334:Heart Function Tests; D006801:Humans; D007902:Length of Stay; D008297:Male; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000628:therapy*