Right Ventricular Outflow-tract Fractional Shortening: an Applicable Measure of Right Ventricular Systolic Function

Aims: Assessment of right ventricular function is important. However, this is not easy to achieve due to the complex anatomy and geometry of the right ventricle, making the evaluation of its function limited. Therefore, a simple reliable and easy method is needed. This study was performed (1) to evaluate the use of right ventricular outflow tract fractional shortening obtained by M-mode echocardiography as a measure of right ventricular systolic function and (2) to determine the relationship between this parameter and other established measurements of right ventricular function such as long axis excursion.

Methods And Results: Ninety-two consecutive patients referred for echocardiographic assessment of left and right ventricular function, age mean+/-SD was 68+/-14 years, were investigated. Twenty healthy controls, age 46+/-12 years were also studied. M-mode echocardiography was used to measure right ventricular outflow tract fractional shortening and right ventricular long axis excursion. Doppler echocardiography was used for the estimation of right ventricular-right atrial pressure drop and pulmonary artery acceleration time. Right ventricular outflow tract fractional shortening (P<0.0001), right ventricular long axis excursion (P<0.0001) and pulmonary acceleration time (P<0.0001) were reduced in patients compared to controls. Right ventricular outflow tract fractional shortening correlated with long axis excursion (r=0.66 P<0.0001), pulmonary artery acceleration time (r=0.80 P<0.0001) and right ventricular-right atrial pressure drop (r=-0.53 P<0.0001). Right ventricular long axis excursion correlated with right ventricular-right atrial pressure drop though to a lesser significance (r=-0.27 P <0.001). Furthermore, right ventricular outflow tract fractional shortening was reduced in patients with pulmonary hypertension compared to patients without, this difference was not observed in the right ventricular systolic long axis excursion.

Conclusion: Right ventricular outflow tract fractional shortening provides a simple and non-invasive measure of right ventricular systolic function. In combination with long axis excursion and Doppler velocities they should provide comprehensive assessment of right ventricular function.