title: The presence of electromechanical mismatch in nonischemic dilated cardiomyopathy is associated with ventricular repolarization instability.
abstract: BACKGROUND
  We analyzed electromechanical mismatch (EMM) and its relationship to ventricular repolarization in patients with nonischemic dilated cardiomyopathy (DCM).
  
  
  RESULTS
  In 39 DCM patients with left ventricular ejection fraction (LVEF) <40% and New York Heart Association functional class ≥III, electroanatomic mapping was used to quantify areas of EMM. High-resolution electrocardiograph was used to measure heart rate variability (HRV) and QT variability index (QTVI). EMM was present in 22 patients (56%, group 1), whereas 17 patients presented no mismatched segments (44%, group 2). The groups did not differ in age (56 ± 10 years in group 1 vs 57 ± 7 years in group 2; P = .82), sex (male: 82% vs 94%; P = .40), LVEF (27 ± 8% vs 25 ± 6%; P = .18), or N-terminal pro-B-type natriuretic peptide (2,350 pg/mL vs 2,831 pg/mL; P = .32). Although heart rate and HRV were similar in both groups (rate: 80 ± 20 beats/min in group 1 vs 74 ± 19 beats/min in group 2 [P = .47]; standard deviation of normal-to normal RR intervals: 106 ± 79 vs 88 ± 115 [P = .61]), we found significantly higher QTVI values in patients from group 1 (-1.15 ± 0.46 vs -1.62 ± 0.51 in group 2; P = .005). In patients with implantable cardioverter-defibrillators, ventricular arrhythmias recorded ≤1 year before enrollment were more frequent in group 1 than in group 2 (58% vs 13%; P = .02).
  
  
  CONCLUSIONS
  EMM is present in a majority of patients with DCM and is associated with ventricular repolarization instability.
authors.affiliation: Advanced Heart Failure and Transplantation Center, Department of Cardiology, University Medical Center, Ljubljana, Slovenia.
authors.forename: Ursa
authors.initials: U
authors.lastname: Mikuz
authors.affiliation: Advanced Heart Failure and Transplantation Center, Department of Cardiology, University Medical Center, Ljubljana, Slovenia.
authors.forename: Gregor
authors.initials: G
authors.lastname: Poglajen
authors.affiliation: Department of Intensive Care Medicine, University Medical Center, Ljubljana, Slovenia.
authors.forename: Misa
authors.initials: M
authors.lastname: Fister
authors.affiliation: Institute of Physiology, University of Ljubljana School of Medicine, Ljubljana, Slovenia.
authors.forename: Vito
authors.initials: V
authors.lastname: Starc
authors.affiliation: Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California.
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Wu
authors.affiliation: Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California.
authors.forename: Henry
authors.initials: H
authors.lastname: Hsia
authors.affiliation: Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California.
authors.forename: François
authors.initials: F
authors.lastname: Haddad
authors.affiliation: Advanced Heart Failure and Transplantation Center, Department of Cardiology, University Medical Center, Ljubljana, Slovenia; Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California. Electronic address: bvrtovec@stanford.edu.
authors.forename: Bojan
authors.initials: B
authors.lastname: Vrtovec
mesh_terms: D000368:Aged; D018780:Body Surface Potential Mapping / Q000379:methods*; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D002311:Cardiomyopathy, Dilated / Q000175:diagnosis* / Q000401:mortality* / Q000628:therapy; D015331:Cohort Studies; D016757:Death, Sudden, Cardiac; D017147:Defibrillators, Implantable; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis; D011379:Prognosis; D018570:Risk Assessment; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D015996:Survival Rate; D017180:Tachycardia, Ventricular / Q000175:diagnosis*; D016896:Treatment Outcome
keywords: Electromechanical mapping; QT variability; arrhythmia; dilated cardiomyopathy