title: Age- and sex-based reference limits and clinical correlates of myocardial strain and synchrony: the Framingham Heart Study.
abstract: BACKGROUND
  There is rapidly growing interest in applying measures of myocardial strain and synchrony in clinical investigations and in practice; data are limited regarding their reference ranges in healthy individuals.
  
  
  RESULTS
  We performed speckle-tracking-based echocardiographic measures of left ventricular myocardial strain and synchrony in healthy adults (n=739, mean age 63 years, 64% women) without cardiovascular disease. Reference values were estimated using quantile regression. Age- and sex-based upper (97.5th quantile) limits were: -14.4% to -17.1% (women) and -14.4 to -15.2% (men) for longitudinal strain; -22.3% to -24.7% (women) and -17.9% to -23.7% (men) for circumferential strain; 121 to 165 ms (women) and 143 to 230 ms (men) for longitudinal segmental synchrony (SD of regional time-to-peak strains); and 200 to 222 ms (women) and 216 to 303 ms (men) for transverse segmental synchrony. In multivariable analyses, women had ≈1.7% greater longitudinal strain, ≈2.2% greater transverse strain, and ≈3.2% greater circumferential strain (P<0.0001 for all) compared with men. Older age and higher diastolic blood pressure, even within the normal range, were associated with worse transverse segmental synchrony (P<0.001). Overall, covariates contributed to ≤12% of the variation in myocardial strain or synchrony in this healthy sample.
  
  
  CONCLUSIONS
  We estimated age- and sex-specific reference limits for measures of left ventricular strain and synchrony in a healthy community-based sample, wherein clinical covariates contributed to only a modest proportion of the variation. These data may facilitate the interpretation of left ventricular strain-based measures obtained in future clinical research and practice.
authors.affiliation: Framingham Heart Study, Framingham, MA.
authors.forename: Susan
authors.initials: S
authors.lastname: Cheng
authors.forename: Martin G
authors.initials: MG
authors.lastname: Larson
authors.forename: Elizabeth L
authors.initials: EL
authors.lastname: McCabe
authors.forename: Ewa
authors.initials: E
authors.lastname: Osypiuk
authors.forename: Birgitta T
authors.initials: BT
authors.lastname: Lehman
authors.forename: Plamen
authors.initials: P
authors.lastname: Stanchev
authors.forename: Jayashri
authors.initials: J
authors.lastname: Aragam
authors.forename: Emelia J
authors.initials: EJ
authors.lastname: Benjamin
authors.forename: Scott D
authors.initials: SD
authors.lastname: Solomon
authors.forename: Ramachandran S
authors.initials: RS
authors.lastname: Vasan
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D018619:Echocardiography, Doppler, Pulsed / Q000592:standards*; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009200:Myocardial Contraction; D011237:Predictive Value of Tests; D012016:Reference Values; D012737:Sex Factors; D013314:Stress, Mechanical; D016277:Ventricular Function, Left
keywords: echocardiography; left ventricular function; reference values
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