title: Electrical and mechanical dyssynchrony for prediction of cardiac events in patients with systolic heart failure.
abstract: BACKGROUND
  Recent clinical trials have challenged the clinical applicability of mechanical dyssynchrony in predicting cardiac resynchronisation therapy response.
  
  
  OBJECTIVE
  To evaluate whether mechanical dyssynchrony has an additional benefit over QRS duration in predicting cardiac events in patients with systolic heart failure.
  
  
  METHODS
  A total 167 patients admitted to hospital with heart failure (age 65+/-12, ejection fraction <35%) were followed up prospectively. Using tissue Doppler imaging (TDI), the time to peak systolic velocity during the ejection phase was measured in the basal septal and lateral segments. A temporal difference between the septal to lateral wall (Ts-l) of > or =65 ms was defined as a mechanical dyssynchrony.
  
  
  RESULTS
  After 33 months of follow-up, 70 patients (41.9%) had cardiac events, including 42 (25.1%) with cardiac death. The event-free survival time decreased as Ts-l or QRS duration increased. Patients with QRS > or =120 ms had increased risks of cardiac events by multivariate Cox proportional hazard analysis (HR=1.88, 95% CI 1.07 to 3.29, p = 0.028). The presence of mechanical dyssynchrony also predicted an increased risk of cardiac events (HR=2.37, 95% CI 1.39 to 4.04, p = 0.002). Those with both electrical and mechanical dyssynchrony had a HR of 3.98 (95% CI 2.02 to 7.86, p <0.001) when compared with those with normal QRS duration and absence of mechanical dyssynchrony. The addition of mechanical dyssynchrony significantly improved the prognostic power of a model containing echocardiographic parameters and QRS duration.
  
  
  CONCLUSIONS
  TDI-derived mechanical dyssynchrony is an important prognosticator and independently associated with QRS duration in predicting adverse events in patients with systolic heart failure.
authors.affiliation: Division of Cardiology, Seoul National University Bundang Hospital, Seoul National University, Seoul, South Korea. cardioch@medimail.co.kr
authors.forename: Goo-Yeong
authors.initials: GY
authors.lastname: Cho
authors.forename: Hyung-Kwan
authors.initials: HK
authors.lastname: Kim
authors.forename: Yong-Jin
authors.initials: YJ
authors.lastname: Kim
authors.forename: Dong-Ju
authors.initials: DJ
authors.lastname: Choi
authors.forename: Dae-Won
authors.initials: DW
authors.lastname: Sohn
authors.forename: Byung-Hee
authors.initials: BH
authors.lastname: Oh
authors.forename: Young-Bae
authors.initials: YB
authors.lastname: Park
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology; D002304:Cardiac Pacing, Artificial; D004812:Epidemiologic Methods; D005260:Female; D054143:Heart Failure, Systolic / Q000150:complications / Q000175:diagnosis / Q000401:mortality; D006801:Humans; D008297:Male; D014463:Ultrasonography; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology