title: Biventricular pacing for patients with severe congestive heart failure: a single center experience.
abstract: BACKGROUND
  Biventricular pacing is becoming more and more popular as a therapeutic strategy for patients with severe congestive heart failure refractory to medical treatment. The aim of our study was to evaluate the outcome of resynchronization therapy on the clinical and echocardiographic statuses, to determine whether any factors were predictive of a positive or negative results after biventricular pacing and to analyze the survival curves.
  
  
  METHODS
  From October 1998 to April 2002, 96 patients were selected for biventricular pacing at our center. The implant was successful in 95 (99%) patients. We followed-up the patients at 1, 3 and 6 months and then every 6 months. Follow-up evaluation included a clinical visit, an echocardiogram for the determination of left ventricular diameters, ejection fraction, E and A wave velocities, E/A ratio, E wave deceleration time, entity of mitral regurgitation (calculated as the percentage of the left atrium occupied by the mitral regurgitant jet) and aorto-pulmonary delay (mechanical delay).
  
  
  RESULTS
  Sixty-eight of our 96 patients were followed for at least 6 months. We observed a significant reduction in the electrical (QRS from 177 +/- 30 to 143 +/- 23 ms) and mechanical delay (aorto-pulmonary delay from 55 +/- 33 to 25 +/- 19 ms). We also observed a significant clinical improvement, as demonstrated by the reduction in the NYHA functional class (from 3.2 +/- 0.5 to 2.1 +/- 0.8). This clinical improvement was reflected by the increase in ejection fraction (from 23 +/- 8 to 36 +/- 12%), by the decrease in mitral regurgitation (from 21 +/- 18 to 12 +/- 12%) and by the increase in E wave deceleration time (from 165 +/- 94 to 210 +/- 93 ms). Eight patients died during the first year of follow-up, with a mortality rate of 13%. The 2- and 3-year mortality rates were both 25.4%.
  
  
  CONCLUSIONS
  Even though not randomized, our study enrolled a very homogeneous population of unselected patients; nevertheless, it seems to confirm that biventricular pacing is effective in improving the clinical and instrumental statuses of patients with severe congestive heart failure. Furthermore, it seems to indicate that this treatment could be effective in reducing the mortality rate among such patients.
authors.affiliation: Laboratory of Electrophysiology, Division of Cardiology, University of Brescia, Brescia, Italy. gmascioli@inwind.it
authors.forename: Giosuè
authors.initials: G
authors.lastname: Mascioli
authors.forename: Antonio
authors.initials: A
authors.lastname: Curnis
authors.forename: Luca
authors.initials: L
authors.lastname: Bontempi
authors.forename: Livio
authors.initials: L
authors.lastname: Dei Cas
mesh_terms: D000206:Actuarial Analysis; D000368:Aged; D001783:Blood Flow Velocity; D002304:Cardiac Pacing, Artificial; D015150:Echocardiography, Doppler; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016019:Survival Analysis; D016896:Treatment Outcome