title: Presence of extensive LV remodeling limits the benefits of CRT in patients with intraventricular dyssynchrony.
abstract: OBJECTIVE
  The aim of this study was to evaluate whether, in patients with evidence of both electrical and mechanical left ventricular (LV) dyssynchrony, extensive LV dilation would affect response to cardiac resynchronization therapy (CRT).
  
  
  BACKGROUND
  Cardiac resynchronization therapy is effective in heart failure patients with LV dysfunction and wide QRS complex. However, many patients still fail to respond. We hypothesized that presence of extensive LV dilation might prevent response to CRT, despite LV mechanical dyssynchrony.
  
  
  METHODS
  We studied 78 heart failure patients (68 ± 9 years of age, 77% men) with both electrical (QRS width >120 ms) and mechanical intraventricular dyssynchrony (by tissue Doppler imaging and/or left lateral wall post-systolic contraction). Echocardiographic evaluation was performed at baseline and 6 to 8 months after CRT. As an indication of LV remodeling, end-diastolic volume index and end-systolic volume index (ESVI) and sphericity index were measured. Long-term (40 ± 23 months) clinical follow-up (events: cardiac death and hospital admission for heart failure) was also obtained.
  
  
  RESULTS
  At follow-up after CRT, in the overall population, ejection fraction increased from 26 ± 6% to 35 ± 11% (p < 0.0001), whereas end-diastolic volume index (from 144 ± 43 ml/m(2) to 119 ± 55 ml/m(2)), ESVI (from 108 ± 37 ml/m(2) to 82 ± 49 ml/m(2), p < 0.0001 for both), and sphericity index (from 0.60 ± 0.22 to 0.53 ± 0.15, p = 0.0036) all significantly decreased. By multiple linear regression analysis, after controlling for confounding factors, change in LV ejection fraction at follow-up resulted independently and negatively associated with baseline ESVI (p = 0.001), with much lower improvement after implant in the highest tertile of baseline ESVI. During follow-up, 31 patients (39.7%) had a cardiac event. By Cox regression model, baseline ESVI was the most powerful predictor of events, with event-rate/year increasing with increasing tertiles of ESVI (6.3%, 10.1%, and 23.8%, respectively, p < 0.05).
  
  
  CONCLUSIONS
  In this nonrandomized, open-label clinical study, despite intraventricular electrical and mechanical dyssynchrony, extensive LV remodeling at baseline negatively impacted CRT results in terms of LV function improvement and incidence of cardiac events at follow-up.
authors: Division of Cardiology, University of Perugia School of Medicine, Perugia, Italy.
authors: Erberto
authors: E
authors: Carluccio
authors: Paolo
authors: P
authors: Biagioli
authors: Gianfranco
authors: G
authors: Alunni
authors: Adriano
authors: A
authors: Murrone
authors: Paola
authors: P
authors: Pantano
authors: Emilia
authors: E
authors: Biscottini
authors: Cinzia
authors: C
authors: Zuchi
authors: Gianluca
authors: G
authors: Zingarini
authors: Claudio
authors: C
authors: Cavallini
authors: Giuseppe
authors: G
authors: Ambrosio
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000401:mortality; D016009:Chi-Square Distribution; D018618:Echocardiography, Doppler, Color; D018619:Echocardiography, Doppler, Pulsed; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006333:Heart Failure / Q000150:complications / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000150:complications* / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology; D007558:Italy; D053208:Kaplan-Meier Estimate; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000150:complications* / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling