Agreement between visually estimated left ventricular ejection fraction on echocardiography and quantitative measurements using cardiac magnetic resonance.

Abstract

Visual estimation of left ventricular ejection fraction (LVEF) is still used in routine clinical practice. However, most of the studies evaluating the agreement between the visually estimated LVEF (ve-LVEF) and quantitatively measured LVEF (qm-LVEF) either have not used appropriate statistical methods or gold standard imaging modality. In this study, we aimed to assess the agreement between the ve-LVEF and qm-LVEF using contemporary statistical methods and cardiac magnetic resonance imaging (CMRI). In 54 subjects who underwent 1.5-T CMRI, echocardiographic images were recorded after the CMRI procedure on the same day. Two independent observers estimated ve-LVEFs on echocardiographic records in a random and blinded fashion, and qm-LVEF was obtained by CMRI. Agreement between the ve-LVEF and qm-LVEF values and intra/interobserver ve-LVEF estimations were assessed using intraclass correlation coefficient (ICC), Bland-Altman analysis, and kappa statistics. There was a high agreement between the ve-LVEF and qm-LVEF (ICC 0.93, 95% confidence interval 0.88-0.96). Bland-Altman analysis also demonstrated a good agreement between ve-LVEF and qm-LVEF with ve-LVEF, on average, being 0.6% lower than that obtained by CMRI (mean -0.6, limits of agreement -10.5 and +9.3). A good agreement was also observed for LVEF categories ≤35%, 36%-54%, and ≥55% (unweighted kappa 0.71, linearly weighted kappa 0.76); and LVEF of <55% and ≥55% (kappa 0.80). Intra/inter observer agreement was good for ve-LVEFs (ICC value 0.96 and 0.91, respectively). Visual approach for LVEF assessment may be used for rapid assessment of left ventricular systolic function in clinical practice, particularly in patients with good image quality.