title: Mechanical Dyssynchrony and Abnormal Regional Strain Promote Erroneous Measurement of Systolic Function in Pediatric Heart Transplantation.
abstract: BACKGROUND
  Clinical experience suggests that measurement of left ventricular (LV) ejection fraction (EF) using two-dimensional echocardiography (2DE) is often at variance with results of three-dimensional echocardiography (3DE) in patients who have undergone heart transplantation (HT). The aim of this study was to test the hypothesis that LV mechanical dyssynchrony and abnormal regional strain are present in asymptomatic pediatric HT patients and that they promote errors in the measurement of LV function when 2DE is used.
  
  
  METHODS
  HT subjects and normal volunteer children were prospectively enrolled. All had normal estimated right ventricular systolic pressure and function. LV EF, global and regional strain, and systolic dyssynchrony index (SDI) were quantified using real time 3DE. SDI was determined from volume-time curves of the 16 LV segments and expressed as the standard deviation of the heart rate-corrected time to reach minimal segmental systolic volume. Septal strain was defined as the average of five segments in the interventricular septum. In addition to 3DE, the Teichholz, biplane Simpson, and bullet (5/6 area-length) methods were used to measure EF using 2DE in each subject. Ninety-three examinations were done: 40 in the 40 normal control subjects (mean age, 14.6 ± 10.6 years; 10 male) and 53 in 36 HT subjects (mean age, 10.3 ± 6.2 years; 21 male).
  
  
  RESULTS
  SDI was greater in HT patients (mean, 6.2 ± 4.3%) than in normal controls (mean, 2.2 ± 1.1%) (P < .0001). Global and septal strain was lower in HT patients than in normal controls. EF divergence (absolute difference between two- and three-dimensional EFs) was greater in HT patients (mean, 3.8 ± 2.2%) than in normal controls (mean, 0.7 ± 0.5%) (P < .0001). EF divergence had a strong positive correlation with SDI (adjusted r² = 0.46, P < .001) and negative correlations with all measures of strain (range of adjusted r² values, 0.13-0.32). SDI had no particular relation to LV mass or to QRS duration.
  
  
  CONCLUSIONS
  Children after HT have abnormal LV mechanics characterized by greater dyssynchrony and lower strain. These features correlate with, and possibly contribute to differences between measurements by 2DE and 3DE. EF should be calculated using 3DE in this population and others with dyssynchrony and regional strain abnormalities.
authors.affiliation: Children's Mercy Hospitals and Clinics and the University of Missouri Kansas City School of Medicine, Kansas City, Missouri.
authors.forename: Anitha
authors.initials: A
authors.lastname: Parthiban
authors.affiliation: Children's Hospital and Medical Center and the University of Nebraska Medical Center, Omaha, Nebraska.
authors.forename: Ling
authors.initials: L
authors.lastname: Li
authors.affiliation: Children's Hospital and Medical Center and the University of Nebraska Medical Center, Omaha, Nebraska.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Kindel
authors.affiliation: Children's Mercy Hospitals and Clinics and the University of Missouri Kansas City School of Medicine, Kansas City, Missouri.
authors.forename: Girish
authors.initials: G
authors.lastname: Shirali
authors.affiliation: Children's Hospital and Medical Center and the University of Nebraska Medical Center, Omaha, Nebraska.
authors.forename: Barbara
authors.initials: B
authors.lastname: Roessner
authors.affiliation: Children's Mercy Hospitals and Clinics and the University of Missouri Kansas City School of Medicine, Kansas City, Missouri.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Marshall
authors.affiliation: Department of Cardiology and Pneumology, University Medical Center, Georg-August-University, Göttingen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schuster
authors.affiliation: TomTec Imaging Systems GmbH, Corrales, New Mexico.
authors.forename: Berthold
authors.initials: B
authors.lastname: Klas
authors.affiliation: Children's Hospital and Medical Center and the University of Nebraska Medical Center, Omaha, Nebraska.
authors.forename: David A
authors.initials: DA
authors.lastname: Danford
authors.affiliation: Children's Hospital and Medical Center and the University of Nebraska Medical Center, Omaha, Nebraska. Electronic address: skutty@unmc.edu.
authors.forename: Shelby
authors.initials: S
authors.lastname: Kutty
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D016022:Case-Control Studies; D004452:Echocardiography / Q000379:methods; D019560:Echocardiography, Three-Dimensional; D005500:Follow-Up Studies; D006084:Graft Rejection / Q000000981:diagnostic imaging / Q000453:epidemiology; D016027:Heart Transplantation / Q000009:adverse effects / Q000379:methods; D015588:Observer Variation; D010372:Pediatrics; D011446:Prospective Studies; D012016:Reference Values; D012044:Regression Analysis; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013318:Stroke Volume / Q000502:physiology; D013599:Systole / Q000502:physiology; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology
keywords: Dyssynchrony; Heart transplantation; Left ventricular function; Pediatric; Strain; Three-dimensional echocardiography