title: Reverse left ventricular remodeling is more likely in non ischemic cardiomyopathy patients upgraded to biventricular stimulation after chronic right ventricular pacing.
abstract: BACKGROUND
  Chronic right ventricular (RV) apical pacing may lead to left ventricular (LV) dyssynchrony and LV dysfunction. In heart failure due to RV pacing, upgrading to biventricular stimulation (CRT) can improve NYHA Class and LV function. A proportion of patients do not respond to upgrading. Aim was to assess whether etiology of LV dysfunction accounts for responses to CRT in RV-paced patients.
  
  
  METHODS
  Sixty-two patients treated by CRT, under RV pacing from 50.2 ± 5.4 months, were studied. Cause of LV dysfunction was non-ischemic (NIC) in 28 and ischemic cardiomyopathy (IC) in 34 patients. Clinical and conventional echocardiographic parameters were available within 1 month before RV pacing, within 1 month before CRT and at 12 ± 2 months of follow-up (FU).
  
  
  RESULTS
  Decreased LVEF (from 37.0 ± 8.8 to 25.6 ± 6.1%, p <0.001), increased LV end-systolic dimensions (LVESD) (from 48.1 ± 8.6 to 55.2 ± 7.9 mm, p <0.001) and worsened NYHA Class (from 1.9 ± 1.1 to 3.2 ± .6, p < 0.005) were found before CRT, compared to pre RV-pacing. After CRT, 44/62 patients showed a ≥ 1 NYHA Class improvement; >10% decrease in LVESD was observed in 24 patients: 5 with IC, 19 with NIC (p < .0.001). The association between cause of LV dysfunction with >10% decrease in LVESD remained highly significant (p < 0.001) adjusting for pre-CRT QRS duration, NYHA Class, LVEF, LVESD, treatment or RV pacing duration.
  
  
  CONCLUSIONS
  CRT improves functional class even after long-lasting pacing. Reverse remodeling is evident in a small population, more likely with NIC.
authors.affiliation: CNR Clinical Physiology Institute, Pisa, Italy. morales@ifc.cnr.it
authors.forename: Maria-Aurora
authors.initials: MA
authors.lastname: Morales
authors.forename: Umberto
authors.initials: U
authors.lastname: Startari
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Rossi
authors.forename: Luca
authors.initials: L
authors.lastname: Panchetti
authors.forename: Andrea
authors.initials: A
authors.lastname: Rossi
authors.forename: Marcello
authors.initials: M
authors.lastname: Piacenti
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy; D009202:Cardiomyopathies / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D013318:Stroke Volume / Q000502:physiology; D014463:Ultrasonography; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy; D020257:Ventricular Remodeling / Q000502:physiology*