title: Reference Values for Right Ventricular Strain in Patients without Cardiopulmonary Disease: A Prospective Evaluation and Meta-Analysis.
abstract: BACKGROUND
  Myocardial strain imaging is a sensitive echocardiographic technique for identifying ventricular dysfunction. The aim of this study was to describe a reference range for right ventricular (RV) strain in subjects without cardiopulmonary disease and to report these values from a systematic review and meta-analysis of the current literature.
  
  
  METHODS
  Prospective online measurement of RV free wall longitudinal systolic strain using speckle tracking echocardiography (STE) was performed in 116 subjects with normal echocardiograms and without cardiopulmonary disease or risk factors. A systematic search of studies in EMBASE and Medline reporting RV strain values was performed through February 2014.
  
  
  RESULTS
  The mean age was 48 ± 16 years and 58% were female. Mean RV strain was -26 ± 4%. Ten studies involving a total of 486 patients met our inclusion criteria. The mean age range was 43-57 years and 59% were female. All prior studies were performed with offline strain analysis, and 9 used a GE Healthcare strain analysis software system. The weighted estimate of RV free wall strain measured using tissue Doppler imaging (4 studies) was -27 ± 1% (95% confidence interval [CI] -30% to -25%) and with STE (8 studies, including the current study data) -27 ± 2% (95% CI -29% to -24%), respectively.
  
  
  CONCLUSIONS
  A reference range for RV strain in subjects without cardiopulmonary disease is presented. These data may help facilitate the routine clinical measurement of RV strain in patients referred for right heart echocardiography assessment.
authors.affiliation: Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota.
authors.forename: Nowell M
authors.initials: NM
authors.lastname: Fine
authors.forename: Libo
authors.initials: L
authors.lastname: Chen
authors.forename: Paul M
authors.initials: PM
authors.lastname: Bastiansen
authors.forename: Robert P
authors.initials: RP
authors.lastname: Frantz
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Pellikka
authors.forename: Jae K
authors.initials: JK
authors.lastname: Oh
authors.forename: Garvan C
authors.initials: GC
authors.lastname: Kane
mesh_terms: D000328:Adult; D002318:Cardiovascular Diseases / Q000150:complications* / Q000000981:diagnostic imaging*; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006801:Humans; D008171:Lung Diseases / Q000150:complications* / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012016:Reference Values; D014463:Ultrasonography; D018497:Ventricular Dysfunction, Right / Q000150:complications* / Q000000981:diagnostic imaging*
keywords: meta-analysis; reference range; right ventricle; speckle tracking echocardiography; strain