Two-Dimensional Speckle-Tracking Echocardiography in Normal Korean Population: Is Now to Start Using in Routine Clinical Practice?

Left ventricle (LV) strain measurement by using the two-dimensional (2D) speckle-tracking echocardiography (STE) was first described in 2004, 1) and has been widely applied in research , and the number of publications in the medical literature regarding the clinical utility of STE has been grown rapidly. 2)3) STE is based on frame-by-frame image tracking of tiny natural acoustic markers within the myocardium and subsequent measurement of LV deformation. 4) Assessment of strain by 2D STE is now present as a semiautomatic method in many ultrasound vendors and in off-line programs. Moreover, several previous reports have demonstrated the usefulness of STE-derived global longitudinal strain (GLS) as a novel echocardio-graphic methodology of cardiac function, which has been demonstrated as a prognostic value in the general population, 3) in patients with myocardial infarction, 5) and in heart failure patients with preserved and reduced LV ejection fraction (LVEF). 6) However, in spite of long experience and confidential results , STE has not yet fully adopted in routine clinical practice , as the robustness of the method has been in doubt mainly due to insufficient reproducibility and vendor dependency of measurement itself. 7) In addition, the reason of variability of strain parameters are diverse which are influenced by patient (age, gender, race), hemodynamic (blood pressure, heart rate), and cardiac (LV chamber size, wall thickness) factors limits its usage in real practice. Hence, the routine use of myocardial strain in clinical practice essentially requires the definition of a normal range first. The article of Park et al. 8) in this issue of the Journal of Cardiovascular Ultrasound, tried to address these issues and to define STE based normal values for LV GLS in the Korean population by conducting a multicenter study of healthy volunteers. In this study, to minimize the vendor dependency and inter-observer variation of strain values, authors used acquired images from GE Medical Systems (Horten, Norway) only and analyzed the data in the Core lab by one researcher. The main results of this study can be summarized as follows: in total of 501 subjects, 1) normal reference values of LV GLS and strain rate was-20.4 ± 2.2% [95% confidence interval (CI)), respectively, and there was modest correlation between LVEF and GLS (r =-0.296, p < 0.001) or GLS rate (GLSR; r =-0.271, p < 0.001); 2) GLS and GLSR values were significantly more negative in women than in men; and 3) age was not …