Table 6.
Core laboratory measurements: Twenty variables with the lowest inter- and intra-observer % error with 3-beat averaging.
| Inter-observer mean % error | Intra-observer mean % error | ||||
|---|---|---|---|---|---|
| Variable name | Variable type |
% error |
Variable name | Variable type |
% error |
| LV function: Eccentricity index | 2D | 0.90 | LV function: Eccentricity index | 2D | 0.33 |
| Septal STD: Isovolumic contraction onset to isovolumic relaxation end* | Tissue Doppler, time | 3.2 | LV ED 4-ch epicardial long axis dimension* | 2D | 0.67 |
| Mitral valve peak early diastolic velocity | Doppler, velocity | 3.2 | LV ED 4-ch endocardial long axis dimension* | 2D | 0.71 |
| Aortic valve ejection time | Doppler, time | 3.6 | LV ES 4-ch endocardial long axis dimension* | 2D | 0.80 |
| LV ED 4-ch long axis epicardial dimension* | 2D | 3.7 | LV ED short axis epicardial area* | 2D | 0.89 |
| LV ED short axis dimension* | 2D | 3.8 | LV ED short axis endocardial area | 2D | 0.93 |
| LV ED short axis dimension* | M-mode | 3.8 | LV ES short axis endocardial area | 2D | 1.0 |
| Mitral valve closure time | Doppler, time | 3.9 | Area-length end-diastolic volume | 2D (2) | 1.2 |
| LV ES short axis dimension* | 2D | 4.0 | LV ED 4-ch long axis epicardial area* | 2D | 1.3 |
| LV ED 4-ch endocardial long axis dimension* | 2D | 4.0 | Area-length end-systolic volume | 2D, 2 | 1.3 |
| Simultaneous mitral and aortic valve Doppler: Ejection time | Doppler, time | 4.2 | LV ED 4-ch long axis endocardial area | 2D | 1.4 |
| Left STD isovolumic contraction onset to isovolumic relaxation end | Tissue Doppler, time | 4.2 | LV ES 4-ch long axis endocardial area (2D) | 2D | 1.5 |
| Aortic valve: Peak velocity | Doppler, velocity | 4.3 | LV ED short axis dimension* | M-mode | 1.5 |
| LV ES 4-ch endocardial long axis dimension* | 2D | 4.4 | LV ED short axis dimension* | 2D | 1.6 |
| Septal STD ejection time | Tissue Doppler, time | 4.5 | LV ED 2-ch long axis epicardial area | 2D | 1.7 |
| Aortic annulus diameter | 2D | 4.5 | LV ES short axis dimension | M-mode | 1.8 |
| Right STD isovolumic contraction onset to isovolumic relaxation end | Tissue Doppler, time | 4.6 | LV sphericity index | 2D, 2 | 1.9 |
| Right STD peak systolic velocity | Tissue Doppler, velocity | 4.7 | LV ES short axis dimension* | 2D | 1.9 |
| LV ED short axis epicardial area* | 2D | 4.7 | Mod-Simpsons end-diastolic volume | 2D, 2 | 2.0 |
| LV ED 4-ch long axis epicardial area* | 2D | 4.8 | LV ED 2-chamber long axis endocardial area | 2D | 2.1 |
2D = two-dimensional; 2-ch = 2-chamber; 4-ch = 4-chamber; ED = end-diastolic; ES = end-systolic; LV = left ventricle; M = M-mode; STD: spectral tissue Doppler. For calculated variables, the number of variables used to calculate these is in parentheses. Measurements of heart rate have been excluded from this table.
An asterisk ‘*’ marks the variables that feature among the 20 variables for both the lowest inter-observer and the lowest intra-observer % error at the core laboratory.