title: Predictors of myocardial recovery in pediatric tachycardia-induced cardiomyopathy.
abstract: BACKGROUND
  Tachycardia-induced cardiomyopathy (TIC) carries significant risk of morbidity and mortality, although full recovery is possible. Little is known about the myocardial recovery pattern.
  
  
  OBJECTIVE
  The purpose of this study was to determine the time course and predictors of myocardial recovery in pediatric TIC.
  
  
  METHODS
  An international multicenter study of pediatric TIC was conducted. Children ≤18 years with incessant tachyarrhythmia, cardiac dysfunction (left ventricular ejection fraction [LVEF] <50%), and left ventricular (LV) dilation (left ventricular end-diastolic dimension [LVEDD] z-score ≥2) were included. Children with congenital heart disease or suspected primary cardiomyopathy were excluded. Primary end-points were time to LV systolic functional recovery (LVEF ≥55%) and normal LV size (LVEDD z-score <2).
  
  
  RESULTS
  Eighty-one children from 17 centers met inclusion criteria: median age 4.0 years (range 0.0-17.5 years) and baseline LVEF 28% (interquartile range 19-39). The most common arrhythmias were ectopic atrial tachycardia (59%), permanent junctional reciprocating tachycardia (23%), and ventricular tachycardia (7%). Thirteen required extracorporeal membrane oxygenation (n = 11) or ventricular assist device (n = 2) support. Median time to recovery was 51 days for LVEF and 71 days for LVEDD. Two (4%) underwent heart transplantation, and 1 died (1%). Multivariate predictors of LV systolic functional recovery were age (hazard ratio [HR] 0.61, P = .040), standardized tachycardia rate (HR 1.16, P = .015), mechanical circulatory support (HR 2.61, P = .044), and LVEF (HR 1.33 per 10% increase, p=0.005). For normalization of LV size, only baseline LVEDD (HR 0.86, P = .008) was predictive.
  
  
  CONCLUSIONS
  Pediatric TIC resolves in a predictable fashion. Factors associated with faster recovery include younger age, higher presenting heart rate, use of mechanical circulatory support, and higher LVEF, whereas only smaller baseline LV size predicts reverse remodeling. This knowledge may be useful for clinical evaluation and follow-up of affected children.
authors.affiliation: Division of Pediatric Cardiology, UCLA Medical Center, Los Angeles, California. Electronic address: jpmoore@mednet.ucla.edu.
authors.forename: Jeremy P
authors.initials: JP
authors.lastname: Moore
authors.affiliation: Division of Pediatric Cardiology, UCLA Medical Center, Los Angeles, California.
authors.forename: Payal A
authors.initials: PA
authors.lastname: Patel
authors.affiliation: Division of Pediatric Cardiology, UCLA Medical Center, Los Angeles, California.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Shannon
authors.affiliation: Department of Pediatrics, Seattle Children's Hospital, Seattle, Washington.
authors.forename: Erin L
authors.initials: EL
authors.lastname: Albers
authors.affiliation: Department of Pediatrics, Seattle Children's Hospital, Seattle, Washington.
authors.forename: Jack C
authors.initials: JC
authors.lastname: Salerno
authors.affiliation: Division of Cardiology, The Hospital for Sick Children/University of Toronto, Toronto, Canada.
authors.forename: Maya A
authors.initials: MA
authors.lastname: Stein
authors.affiliation: Division of Cardiology, The Hospital for Sick Children/University of Toronto, Toronto, Canada.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Stephenson
authors.affiliation: Department of Pediatric Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
authors.forename: Shaun
authors.initials: S
authors.lastname: Mohan
authors.affiliation: Department of Pediatric Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
authors.forename: Maully J
authors.initials: MJ
authors.lastname: Shah
authors.affiliation: The Royal Children's Hospital, MCRI and University of Melbourne, Melbourne, Australia.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Asakai
authors.affiliation: The Royal Children's Hospital, MCRI and University of Melbourne, Melbourne, Australia.
authors.forename: Andreas
authors.initials: A
authors.lastname: Pflaumer
authors.affiliation: The Heart Center, Cincinnati Children's Hospital, Cincinnati, Ohio.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Czosek
authors.affiliation: Division of Pediatric Cardiology, Primary Children's Medical Center, University of Utah, Salt Lake City, Utah.
authors.forename: Melanie D
authors.initials: MD
authors.lastname: Everitt
authors.affiliation: Division of Pediatric Cardiology, Primary Children's Medical Center, University of Utah, Salt Lake City, Utah.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Garnreiter
authors.affiliation: University of Colorado Denver/Children's Hospital Colorado, Denver, Colorado.
authors.forename: Anthony C
authors.initials: AC
authors.lastname: McCanta
authors.affiliation: Arizona Pediatric Cardiology/Phoenix Children's Hospital, Phoenix, Arizona.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Papez
authors.affiliation: Division of Pediatric Cardiology, University of British Columbia, British Columbia, Canada.
authors.forename: Carolina
authors.initials: C
authors.lastname: Escudero
authors.affiliation: Division of Pediatric Cardiology, University of British Columbia, British Columbia, Canada.
authors.forename: Shubhayan
authors.initials: S
authors.lastname: Sanatani
authors.affiliation: Department of Pediatric Cardiology, Medical University of South Carolina, Charelston, South Carolina.
authors.forename: Nicole B
authors.initials: NB
authors.lastname: Cain
authors.affiliation: Department of Pediatrics, Division of Cardiology, Vanderbilt University School of Medicine and the Monroe Carell Jr. Children's Hospital, Nashville, Tennessee.
authors.forename: Prince J
authors.initials: PJ
authors.lastname: Kannankeril
authors.affiliation: Rady Children's Hospital San Diego, UCSD, La Jolla, California.
authors.forename: Andras
authors.initials: A
authors.lastname: Bratincsak
authors.affiliation: Division of Pediatric Cardiology, Loma Linda University Children's Hospital, Loma Linda, California.
authors.forename: Ravi
authors.initials: R
authors.lastname: Mandapati
authors.affiliation: Department of Pediatric Cardiology, Washington University School of Medicine/St. Louis Children's Hospital, St. Louis, Missouri.
authors.forename: Jennifer N A
authors.initials: JN
authors.lastname: Silva
authors.affiliation: Department of Pediatric Cardiology, Arkansas Children's Hospital, University of Arkansas for Medical Sciences, Little Rock, Arkansas.
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Knecht
authors.affiliation: Department of Pediatrics, Oregon Health and Science University, Portland, Oregon.
authors.forename: Seshadri
authors.initials: S
authors.lastname: Balaji
mesh_terms: D000293:Adolescent; D009202:Cardiomyopathies / Q000209:etiology / Q000503:physiopathology* / Q000628:therapy; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D007223:Infant; D008297:Male; D009206:Myocardium; D011379:Prognosis; D013610:Tachycardia / Q000503:physiopathology* / Q000628:therapy; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology*
keywords: Antiarrhythmic drugs; Cardiomyopathy; Catheter ablation; Supraventricular tachycardia; Ventricular remodeling