Age- and Sex-Based Reference Limits and Clinical Correlates of Myocardial Strain and Synchrony The Framingham Heart Study

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. Methods and 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 approximate to 1.7% greater longitudinal strain, approximate to 2.2% greater transverse strain, and approximate to 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.