title: Sudden cardiac death in adult congenital heart disease: can the unpredictable be foreseen?
abstract: OBJECTIVE
  Sudden cardiac death (SCD) is a major cause of mortality in adults with congenital heart disease (CHD). Several risk factors for SCD including conduction disturbances and ventricular dysfunction have been described previously. However, electrocardiogram (ECG) and echocardiographic parameters may change over time, and the predictive value of such temporal changes, rather than their point estimates, for SCD remains unknown.
  
  
  RESULTS
  This was a retrospective case-control study in adults with CHD and proven or presumed SCD and matched controls. Data were obtained from three databases including 25 000 adults with CHD. Sequential measurements were performed on electrocardiograms and echocardiograms. Ventricular function was assessed by echocardiography and graded on a four-point ordinal scale: 1, normal [ejection fraction (EF) ≥50%]; 2, mildly impaired (EF 40-49%); 3, moderately impaired (EF 30-39%); and 4, severely impaired (EF < 30%). Overall, 131 SCDs (mean age 36 ± 14 years, 67% male) and 260 controls (mean age 37 ± 13 years, 63% male) were included. At baseline, median QRS duration was 108 ms (range 58-168 ms) in SCDs and 97 ms (range 50-168 ms) in controls and increased over time at a rate of 1.6 ± 0.5 vs. 0.5 ± 0.2 ms/year in SCDs and controls, respectively (P = 0.011). QT dispersion at baseline was 61 ms (range 31-168 ms) in SCDs and 50 ms (range 21-129 ms) in controls. QT dispersion increased at a rate of 1.1 ± 0.4 ms/year in SCD victims and decreased at a rate of 0.2 ± 0.2 ms/year in controls (P = 0.004). Increase of QRS duration ≥5 ms/year was associated with an increased risk of SCD [OR 1.9, 95% confidence interval (CI) 1.1-3.3, P = 0.013]. Change from any baseline systemic ventricular function (normal, mild, or moderately impaired) to severe ventricular dysfunction over time was associated with the highest risk of SCD (OR 16.9, 95% CI 1.8-120.1, P = 0.008).
  
  
  CONCLUSIONS
  In adults with CHD, QRS duration and ventricular dysfunction progress over time. Progression of QRS duration and the rate of impairment of ventricular function served to identify those at increased risk of SCD.
authors.affiliation: Department of Cardiology, Academic Medical Center, Amsterdam, The Netherlands.|Interuniversity Cardiology Institute of the Netherlands, Utrecht, The Netherlands.
authors.forename: Zeliha
authors.initials: Z
authors.lastname: Koyak
authors.affiliation: Department of Cardiology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Joris R
authors.initials: JR
authors.lastname: de Groot
authors.affiliation: Department of Cardiology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Berto J
authors.initials: BJ
authors.lastname: Bouma
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Aeilko H
authors.initials: AH
authors.lastname: Zwinderman
authors.affiliation: Department of Cardiology, Peter Munk Cardiac Center, Toronto Congenital Cardiac Center for Adults, and University of Toronto, Toronto, Canada.
authors.forename: Candice K
authors.initials: CK
authors.lastname: Silversides
authors.affiliation: Department of Cardiology, Peter Munk Cardiac Center, Toronto Congenital Cardiac Center for Adults, and University of Toronto, Toronto, Canada.
authors.forename: Erwin N
authors.initials: EN
authors.lastname: Oechslin
authors.affiliation: Department of Cardiology, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Werner
authors.initials: W
authors.lastname: Budts
authors.affiliation: Interuniversity Cardiology Institute of the Netherlands, Utrecht, The Netherlands.|Department of Cardiology, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Isabelle C
authors.initials: IC
authors.lastname: Van Gelder
authors.affiliation: Department of Cardiology, Academic Medical Center, Amsterdam, The Netherlands.|Interuniversity Cardiology Institute of the Netherlands, Utrecht, The Netherlands.
authors.forename: Barbara J M
authors.initials: BJ
authors.lastname: Mulder
authors.affiliation: Department of Cardiology, Peter Munk Cardiac Center, Toronto Congenital Cardiac Center for Adults, and University of Toronto, Toronto, Canada.
authors.forename: Louise
authors.initials: L
authors.lastname: Harris
mesh_terms: D000200:Action Potentials; D000328:Adult; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000209:etiology* / Q000401:mortality / Q000503:physiopathology; D002423:Cause of Death; D016009:Chi-Square Distribution; D016757:Death, Sudden, Cardiac / Q000209:etiology*; D018450:Disease Progression; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006330:Heart Defects, Congenital / Q000150:complications* / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology; D006339:Heart Rate; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D017741:Survivors; D013997:Time Factors; D018754:Ventricular Dysfunction / Q000000981:diagnostic imaging / Q000209:etiology* / Q000401:mortality / Q000503:physiopathology; D016276:Ventricular Function; D055815:Young Adult
keywords: Adult congenital heart disease; Sudden cardiac death; Ventricular arrhythmias