Table 2.
Right atrial strain means and lower limits of normal and 95% confidence intervals by echocardiography strain software in healthy subjects
| Strain vendor software | TomTec | EchoPAC | VVI | Epsilon |
|---|---|---|---|---|
| Number of subjects | 100 | 50 (GE scans only) | 100 | 100 |
| RASr (%) | ||||
| Mean | 41.2 (38.5, 43.0) | 35.9 (34.4, 37.3) | 44.8 (42.3, 47.3) | 38.9 (36.7, 41.0) |
| LLN normal | 29.6 (26.5, 32.7) | 27.0 (24.5, 29.5) | 27.6 (23.3, 31.9) | 25.5 (21.7, 29.3) |
| Intra-reader variability | 4.9 | 2.1 | 9.6 | 4.1 |
| Inter-reader variability | 7.4 | 4.1 | 10.2 | 7.0 |
| RAScd (%) | ||||
| Mean | −25.9 (−27.5, −24.4) | −22.9 (−24.2, −21.5) | −27.6 (−29.8, −25.4) | −24.5 (−26.4, −22.7) |
| LLN normal | −14.3 (−17.1, −11.5) | −14.0 (−16.4 −11.6) | −13.2 (-17.0, -9.4) | −12.5 (−15.7, −9.3) |
| Intra-reader variability | 5.1 | 2.3 | 11.1 | 4.1 |
| Inter-reader variability | 7.7 | 3.8 | 7.8 | 7.0 |
| RASct (%) | ||||
| Mean | −15.3 (−16.2, −14.4) | −12.4 (−13.5, −11.3) | −17.1 (−18.6, −15.5) | −14.3 (−15.2, −13.5) |
| LLN normal | −10.2 (−11.7, −8.7) | −8.0 (−9.9, −6.1) | −8.0 (−10.7, −5.3) | −9.6 (−11.1, −8.1) |
| Intra-reader variability | 3.5 | 1.6 | 5.8 | 3.0 |
| Inter-reader variability | 3.2 | 5.4 | 7.1 | 7.6 |
The mean or lower limits of normal (LLN) and their 95% confidence intervals (95% CI) are presented. Intra- and inter-reader variability is assessed using the standard error of measurement. RASr right atrial reservoir strain, RAScd right atrial conduit strain, RASct right atrial contractile strain, and VVI velocity vector imaging