Purpose: The size of the ventricles of the heart is important to establish during the clinical echocardiographic examination. Due to the complex anatomy of the right ventricle, it is difficult to measure its size at times. One of the most frequently used ways is to measure the right ventricular outflow tract (RVOT1), probably due to its good reproducibility. However, in the literature different ways are described to measure RVOT1, both at different sites and using different methods such as M-mode and 2D. The first aim of the present study was to exam if there is a significant difference in the outcome of RVOT1 using different sites and methods to measure it. The second aim was to study if there is a significant difference between the usually preferred left lateral decubitus position during the echocardiographic examination and the supine decubitus position, which the echocardiographer sometimes can be compelled to use if the patient is unable to lie in the left lateral decubitus position.
Methods: Twenty-seven healthy subjects were included and examined by echocardiography. RVOT1 was measured at different sites using different methods; first with the subject in the left lateral decubitus position and then repeating the same measurements with the subject in the supine decubitus position.
Results: Comparing the RVOT1 measured at different sites and with different methods showed an overall significant difference (p < 0.001). Also when comparing the different body positions, there was an overall significant difference (p = 0.001).
Conclusions: When comparing RVOT1 of the same patient or subject over time, the results from the present study indicate that the same site, method and body position should be used.