title: Cardiac resynchronization therapy in adult patients with repaired tetralogy of fallot and left ventricular systolic dysfunction.
abstract: BACKGROUND
  Although left ventricular (LV) systolic dysfunction is known to occur in adults with repaired Tetralogy of Fallot (TOF), the effects of cardiac resynchronization therapy (CRT) are not well characterized.
  
  
  METHODS
  We retrospectively divided all patients with repaired TOF and impaired LV ejection fraction (LVEF ≤ 40%) undergoing CRT at our institution (n = 10) into two groups: de novo CRT (group A, n = 6) or upgrade from existing device (group B, n = 4). Echocardiograms were reviewed at baseline, medium-term (>6 months post-CRT), and long-term follow-up. CRT response was defined as reduction in LV end-systolic volume (LVESV) ≥15% at medium term.
  
  
  RESULTS
  Age at surgical repair was 13.1 ± 16.0 years, age at CRT was 44.4 ± 12.5 years, and baseline LVEF was 24.0 ± 10.5%. Group A demonstrated a preponderance of right ventricular (RV) conduction delay, whereas all patients in group B demonstrated RV pacing at baseline. At medium-term follow-up, patients in group A showed significant improvements in LVEF, LV end-diastolic volume (LVEDV), and LVESV. Group B also demonstrated a significant improvement in LVEF with favorable trends in LV volumes. Of nine patients with complete data at medium term, eight showed evidence of CRT response. Average long-term follow-up was 53.4 ± 29.3 months. At long-term follow-up, LVEF, LVEDV, and LVESV remained numerically better than baseline, although the results were no longer significant.
  
  
  CONCLUSIONS
  Adult patients with repaired TOF and LV systolic dysfunction demonstrate significant medium-term response to CRT, even among those with RV conduction delay. The long-term impact of CRT in this population requires further characterization.
authors.affiliation: Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Faisal M
authors.initials: FM
authors.lastname: Merchant
authors.forename: Danesh
authors.initials: D
authors.lastname: Kella
authors.forename: Wendy M
authors.initials: WM
authors.lastname: Book
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Langberg
authors.forename: Michael S
authors.initials: MS
authors.lastname: Lloyd
mesh_terms: D000293:Adolescent; D000328:Adult; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000601:surgery*; D006801:Humans; D008297:Male; D019651:Plastic Surgery Procedures / Q000009:adverse effects*; D012189:Retrospective Studies; D013771:Tetralogy of Fallot / Q000150:complications / Q000601:surgery*; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000209:etiology* / Q000517:prevention & control*; D055815:Young Adult
keywords: Tetralogy of Fallot; cardiac resynchronization therapy; congestive heart failure; left ventricle dysfunction