Reproducibility of speckle-tracking-based strain measures of left ventricular function in a community-based study

Abstract

Background: The reproducibility of echocardiographic measurements of myocardial strain, performed in a community-based setting, has not been reported previously.

Methods: The reproducibility of left ventricular strain measurements was examined in two samples of 20 participants each from the Offspring Cohort of the Framingham Heart Study (mean age, 63 ± 9 years; 59% women). Two-dimensional speckle-tracking-based measurements of global peak left ventricular strain in systole were performed in the apical four-chamber, apical two-chamber, and midventricular parasternal short-axis views.

Results: Interobserver intraclass correlation coefficients were ≥0.84 for all global strain measurements, with average coefficients of variation of ≤4% for global longitudinal and circumferential strain and <8% for global transverse and radial strain. For left ventricular strain measurements performed in each of the three views, intraobserver intraclass correlation coefficients were ≥0.91 among time points spanning a total 8-month period. The average coefficients of variation were <6% for global longitudinal and circumferential strain and <9% for global transverse and radial strain. Interobserver and intraobserver reproducibility findings were similar in analyses adjusting for frame rate.

Conclusions: Excellent reproducibility of global longitudinal and circumferential strain measurements and very good reproducibility of global transverse and radial strain measurements were observed. Taken together, these findings demonstrate the reproducibility of performing echocardiographic strain measurements in a large, epidemiologic community-based setting.

Keywords: A2C; A4C; Apical four-chamber; Apical two-chamber; Epidemiology; ICC; Intraclass correlation coefficient; LV; Left ventricular; Myocardial deformation; SAX; Short-axis; Speckle-tracking; Strain.

Figure 1

Representative examples of global left ventricular strain measures obtained from each of the 3 main views: Panel A shows longitudinal and radial strain measured from the A2C view; Panel B shows longitudinal and radial strain measured from the A4C view; and, Panel C shows circumferential and radian strain measured from the SAX view. Colored lines represent strain curves for each of the 6 regional segments over time; black lines represent the global average of strain across the 6 regional segments over time (for each view).

Figure 2

Timing of baseline and follow-up reproducibility analyses performed. See text for description.

Figure 3

Bland-Altman plots are shown for inter-observer variability at baseline for measurements made in each of the 3 main views (Panels A through F). The difference between 2 measurements made (per image) is plotted versus the mean value of the 2 measurements made by: Reader 1 compared to Reader 2 (red circles), Reader 1 compared to Reader 3 (blue triangles), and Reader 2 compared to Reader 3 (green cross bars). All values shown are in % units of strain.

Figure 4

Bland-Altman plots are shown for intra-observer variability, over the course of the measurement period, for measurements made in each of the 3 main views (Panels A through F). The difference between 2 measurements made (per image) is plotted versus the mean value of the 2 measurements made at: Time Point 1 compared to Time Point 2 (red circles), Time Point 1 compared to Time Point 3 (blue triangles), and Time Point 2 compared to Time Point 3 (green cross bars). All values shown are in % units of strain.

Figure 5

Mean (±standard deviation) of measurement values, over the course of the measurement period, are shown for each of the 3 readers: A2C measures of global longitudinal (squares) and transverse (circles) strain for Reader 2 (Panel A), A4C measures of global longitudinal (squares) and transverse (circles) strain for Reader 1 (Panel B), and SAX measures of global circumferential (squares) and0 radial (circles) strain for Reader 3 (Panel C).