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

Background Echocardiography (echo)‐based linear fractional shortening (FS) is widely used to assess left ventricular dysfunction (LVdys), but has not been systematically tested for right ventricular dysfunction (RVdys). Methods The population comprised LVdys patients with and without RVdys (EF<50%) on cardiac MRI (CMR): Echo included standard RV indices (fractional area change [FAC], TAPSE, Sʹ, and FS in parasternal long‐axis (RV outflow tract [RVOT]) and apical four‐chamber views (width [RVWD], length [RVLG]). 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 Sʹ (11.4±2.3 vs 10.0±2.6, all P≤.001) were lower among RVdys patients, as were FS indices (RVOT 32±8 vs 17±10 | RVWD 40±11 vs 22±12 | RVLG 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 Sʹ (r=.31; all P<.001). FS indices decreased stepwise vs CMR RVEF tertiles, as did FAC (all P<.001). In multivariate analysis, FS in RVOT (regression coefficient .51 [CI 0.37‐0.65]), RVWD (0.30 [0.19‐0.41]), and RVLG (0.45 [0.20‐0.71]; all P≤.001) was independently associated with CMR RVEF. FS indices yielded good overall diagnostic performance (AUC: RVOT 0.89 [CI 0.82‐0.97] | RVWD 0.87 [0.78‐0.96] | RVLG 0.80 [0.70‐0.90]; all P<.001) for CMR‐defined RVdy (RVEF<50%). Conclusions RV linear FS provides RV functional indices that parallel CMR RVEF. Parasternal long‐axis RVOT width, four‐chamber RV width, and length are independently associated with RVEF, supporting use of multiple FS indices for RV functional assessment.