title: The prognostic impact of dynamic ventricular dyssynchrony in patients with idiopathic dilated cardiomyopathy and narrow QRS.
abstract: OBJECTIVE
  Asynchronous myocardial contraction adversely influences left ventricular (LV) function and is therefore associated with a poor prognosis in heart failure. Exercise-induced change in ventricular dyssynchrony may be an important determinant of dynamic changes in cardiac output and mitral regurgitation.
  
  
  RESULTS
  A prospective, longitudinal study was designed with pre-defined dyssynchrony index and outcome variables to test the hypothesis that dynamic dyssynchrony is associated with worse long-term event-free survival in patients with dilated cardiomyopathy (DCM) and 'narrow' QRS complex. One-hundred eighty patients (62 ± 8 years; 110 males) with NYHA class II-III, idiopathic DCM, ejection fraction ≤35%, and QRS duration <120 ms were selected. All the patients underwent standard Doppler echo, colour tissue velocity imaging (DTI), and supine bicycle exercise stress echocardiography. Cardiac synchronicity was defined, at rest and at peak exercise, as DTI velocity opposing-wall delay (significant if ≥65 ms). Outcome was defined as freedom from death, heart transplantation, or LV-assist device implantation, over a median follow-up of 48 months, and a Cox proportional hazards model was used for survival analysis. At baseline examination, DCM patients showed a reduced LV ejection fraction (31 + 4%). A significant electromechanical delay in 58 patients (32%). At the peak of physical exercise, a significant electromechanical delay was detected in 103 patients (57%). There were 41 events during the follow-up (23%): 28 cardiac deaths, 8 heart transplantations, and 5 LV-assist device implantations over 4 years. When adjusted for confounding baseline variables, LV end-diastolic volume, restrictive mitral flow pattern, severity of mitral regurgitation, and the presence of exercise-induced intraventricular dyssynchrony were the only independent determinants of an adverse outcome.
  
  
  CONCLUSIONS
  In patients with idiopathic DCM and narrow QRS, the increase in echocardiographic dyssynchrony during exercise was the strongest predictor of less favourable event-free survival.
authors.affiliation: Second University of Naples, Via M. Schipa 44, 80122 Naples, Italy. antonellodandrea@libero.it
authors.forename: Antonello
authors.initials: A
authors.lastname: D'Andrea
authors.forename: Donato
authors.initials: D
authors.lastname: Mele
authors.forename: Stefano
authors.initials: S
authors.lastname: Nistri
authors.forename: Lucia
authors.initials: L
authors.lastname: Riegler
authors.forename: Maurizio
authors.initials: M
authors.lastname: Galderisi
authors.forename: Eustachio
authors.initials: E
authors.lastname: Agricola
authors.forename: Maria Angela
authors.initials: MA
authors.lastname: Losi
authors.forename: Piercarlo
authors.initials: P
authors.lastname: Ballo
authors.forename: Sergio
authors.initials: S
authors.lastname: Mondillo
authors.forename: Luigi P
authors.initials: LP
authors.lastname: Badano
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging* / Q000401:mortality* / Q000628:therapy; D018450:Disease Progression; D025401:Echocardiography, Stress; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012372:ROC Curve; D018570:Risk Assessment; D012720:Severity of Illness Index; D015996:Survival Rate; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy