title: Mechanical dyssynchrony evaluated by tissue Doppler cross-correlation analysis is associated with long-term survival in patients after cardiac resynchronization therapy.
abstract: OBJECTIVE
  Pre-implant assessment of longitudinal mechanical dyssynchrony using cross-correlation analysis (XCA) was tested for association with long-term survival and compared with other tissue Doppler imaging (TDI)-derived indices.
  
  
  RESULTS
  In 131 patients referred for cardiac resynchronization therapy (CRT) from two international centres, mechanical dyssynchrony was assessed from TDI velocity curves using time-to-peak opposing wall delay (OWD) ≥80 ms, Yu index ≥32 ms, and the maximal activation delay (AD-max) >35 ms. AD-max was calculated by XCA of the TDI-derived myocardial acceleration curves. Outcome was a composite of all-cause mortality, cardiac transplantation, or implantation of a ventricular assist device (left ventricular assist device) and modelled using the Cox proportional hazards regression. Follow-up was truncated at 1460 days. Dyssynchrony by AD-max was independently associated with improved survival when adjusted for QRS > 150 ms and aetiology {hazard ratio (HR) 0.35 [95% confidence interval (CI) 0.16-0.77], P = 0.01}. Maximal activation delay performed significantly better than Yu index, OWD, and the presence of left bundle branch block (P < 0.05, all, for difference between parameters). In subgroup analysis, patients without dyssynchrony and QRS between 120 and 150 ms showed a particularly poor survival [HR 4.3 (95% CI 1.46-12.59), P < 0.01, compared with the group with dyssynchrony and QRS between 120 and 150 ms].
  
  
  CONCLUSIONS
  Mechanical dyssynchrony assessed by AD-max was associated with long-term survival after CRT and was significantly better associated compared with other TDI-derived indices. Patients without dyssynchrony and QRS between 120 and 150 ms had a particularly poor prognosis. These results indicate a valuable role for XCA in selection of CRT candidates.
authors.affiliation: Department of Cardiology, Gentofte University Hospital, DK 2900 Hellerup, Denmark. nielsrisum@gmail.com
authors.forename: Niels
authors.initials: N
authors.lastname: Risum
authors.forename: Eric S
authors.initials: ES
authors.lastname: Williams
authors.forename: Michel G
authors.initials: MG
authors.lastname: Khouri
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Jackson
authors.forename: Niels Thue
authors.initials: NT
authors.lastname: Olsen
authors.forename: Christian
authors.initials: C
authors.lastname: Jons
authors.forename: Katrine S
authors.initials: KS
authors.lastname: Storm
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Velazquez
authors.forename: Joseph
authors.initials: J
authors.lastname: Kisslo
authors.forename: Niels Eske
authors.initials: NE
authors.lastname: Bruun
authors.forename: Peter
authors.initials: P
authors.lastname: Sogaard
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy / Q000401:mortality*; D058409:Cardiac Resynchronization Therapy Devices; D003430:Cross-Sectional Studies; D017147:Defibrillators, Implantable; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013318:Stroke Volume / Q000502:physiology; D016896:Treatment Outcome; D018615:Ultrasonography, Doppler, Color; D018487:Ventricular Dysfunction, Left / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*