Background: Tissue Velocity Imaging (TVI) is a method for quantitative analysis of longitudinal myocardial velocities, which can be used during exercise and pharmacological stress echocardiography. It is of interest to evaluate cardiac response to different types of stress tests and the differences between upright and supine bicycle exercise tests have not been fully investigated. Therefore, the aim of this study was to compare cardiac response during supine and upright exercise stress tests.
Method: Twenty young healthy individuals underwent supine and upright stress test. The initial workload was set to 30 W and was increased every minute by a further 30 W until physical exhaustion. Tissue Doppler data from the left ventricle were acquired at the end of every workload level using a GE Vivid7 Dimension system (>200 frames s(-1)). In the off-line processing, isovolumic contraction velocity (IVCV), peak systolic velocity (PSV), isovolumic relaxation velocity (IVRV), peak early diastolic velocity (E') and peak late diastolic velocity (A') were identified at every workload level.
Result: No significant difference between the tests was found in PSV. On the contrary, E' was shown to be significantly higher (P<0.001) during supine exercise than during upright exercise and IVRV was significantly lower (P<0.001) during supine exercise compared to upright exercise.
Conclusion: Upright and supine exercise stress echocardiography give a comparable increase in measured systolic velocities and significant differences in early diastolic velocities.