title: Hemodynamic benefit of multiple programmable pacing configurations in patients with biventricular pacemakers.
abstract: BACKGROUND
  Cardiac resynchronization therapy (CRT) is an established treatment for patients with heart failure. However, one-third of the patients fail to improve with this therapy. Stimulation with different left ventricular stimulation (LVS) configurations has been used to prevent diaphragmatic capture and to decrease the capture thresholds. We evaluated the hemodynamic effects of different LVS configurations using echocardiography.
  
  
  METHODS
  Recipients of CRT systems capable of multiple LVS configurations were studied. Biventricular capture was confirmed for each polarity and echocardiographic measurements were made. The atrioventricular and interventricular delays were optimized and kept constant during the study. The cardiac output (CO), myocardial performance index (MPI), and severity of mitral regurgitation (MR) were recorded for all LVS configurations and compared for the best and the worst configurations, determined by CO.
  
  
  RESULTS
  We studied 10 men and four women, 55 +/- 13 years of age on average. The CO and MPI changed significantly by changing the LVS configurations. The difference in CO ranged from 0.3 to 1.5 L, and seven patients (50%) showed > or =20% difference in CO between best and worst LVS configurations. Severity of MR decreased by > or =1 grade in nine patients, while in two patients MR worsened despite improvement in CO.
  
  
  CONCLUSIONS
  Changing the LVS configuration changes hemodynamic function in some CRT system recipients.
authors.affiliation: CARE Hospitals and CARE Foundation, Hyderabad, India.
authors.forename: Ramprakash
authors.initials: R
authors.lastname: Balasundaram
authors.forename: Hygriv B
authors.initials: HB
authors.lastname: Rao
authors.forename: C
authors.initials: C
authors.lastname: Sridevi
authors.forename: B
authors.initials: B
authors.lastname: Somaraju
authors.forename: Balbir
authors.initials: B
authors.lastname: Singh
authors.forename: Narasimhan
authors.initials: N
authors.lastname: Calambur
mesh_terms: D002304:Cardiac Pacing, Artificial / Q000379:methods*; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000175:diagnosis* / Q000517:prevention & control*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013813:Therapy, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000175:diagnosis* / Q000517:prevention & control*