Systolic efficiency slope (SES) - the S’/ VO2relationship
We took advantage of the linear augmentation pattern of systolic
velocity and its close relationship with VO2 to derive
individual regression lines for VO2 and S’. This new
parameter represents the amount of S’ associated with a 1 unit increase
in VO2 and therefore a measure of myocardial efficiency.
A relationship between the SES slope was observed for
VO2peak and septal S’; r = 0.57; p<0.001 and
lateral S’; r = 0.53; p<0.001) (Figure 3). We also confirmed
the validity of these findings by creating models for OUES, a submaximal
measures shown to predict total cardiopulmonary
capacity10,11. A significant relationship was found
between SES slope and the OUES (septal r = 0.54; p<0.001,
lateral r = 0.52; p=0.001).
Inter- and intraobserver reproducibility
There was excellent inter- and intra-observer reproducibility for all
measurements by CPET (VO2peak and OUES). For
echocardiography parameters there was good to excellent inter- and
intraobserver reproducibility for S’ and E’ at rest and exercise. There
was lower inter- and intraobserver reproducibility seen for LVEF and GLS
both at rest and exercise (Appendix 1).