Echocardiographic linear fractional shortening for quantification of right ventricular systolic function-A cardiac magnetic resonance validation study

Abstract

Background: Echocardiography (echo)-based linear fractional shortening (FS) is widely used to assess left ventricular dysfunction (LV_dys ), but has not been systematically tested for right ventricular dysfunction (RV_dys ).

Methods: The population comprised LV_dys patients with and without RV_dys (EF<50%) on cardiac MRI (CMR): Echo included standard RV indices (fractional area change [FAC], TAPSE, S', and FS in parasternal long-axis (RV outflow tract [RV_OT ]) and apical four-chamber views (width [RV_WD ], length [RV_LG ]).

Results: A total of 168 patients underwent echo and CMR (3±3 days); FAC (46±9 vs 28±11), TAPSE (1.9±0.4 vs 1.5±0.3), and S' (11.4±2.3 vs 10.0±2.6, all P≤.001) were lower among RV_dys patients, as were FS indices (RV_OT 32±8 vs 17±10 | RV_WD 40±11 vs 22±12 | RV_LG 16±5 vs 9±4%; all P<.001). FS indices yielded similar magnitude of correlation with CMR RVEF (r=.73-.56) as did FAC (r=.70), which was slightly higher than TAPSE (r=.47) and S' (r=.31; all P<.001). FS indices decreased stepwise vs CMR RVEF tertiles, as did FAC (all P<.001). In multivariate analysis, FS in RV_OT (regression coefficient .51 [CI 0.37-0.65]), RV_WD (0.30 [0.19-0.41]), and RV_LG (0.45 [0.20-0.71]; all P≤.001) was independently associated with CMR RVEF. FS indices yielded good overall diagnostic performance (AUC: RV_OT 0.89 [CI 0.82-0.97] | RV_WD 0.87 [0.78-0.96] | RV_LG 0.80 [0.70-0.90]; all P<.001) for CMR-defined RV_dy (RVEF<50%).

Conclusions: RV linear FS provides RV functional indices that parallel CMR RVEF. Parasternal long-axis RV_OT width, four-chamber RV width, and length are independently associated with RVEF, supporting use of multiple FS indices for RV functional assessment.

Keywords: cardiovascular magnetic resonance; echocardiography; right ventricle.