Comparison of Left Ventricular Ejection Fraction and Disease Classification by Cardiac Magnetic Resonance and...

This study aimed to assess differences in left ventricular ejection fraction (LVEF) measurements between cardiac magnetic resonance (CMR) and transthoracic echocardiography (TTE) and identify determinants influencing clinical classification discordance. We retrospectively enrolled patients who underwent both CMR and TTE imaging within a 1-week interval. The study endpoint was a comparative analysis of LVEF measurements between 2 modalities. We also assessed the impact of these measurements on clinical decisions, referencing the European Society of Cardiology's heart failure and specific threshold (50%, 35%) classification. Logistic regression was used to explore the association of imaging characteristics with LVEF classification differences. 1,213 patients were included. The median LVEF values were 58% for TTE and 49% for CMR. The modalities demonstrated moderately strong agreement in LVEF measurements (intraclass correlation coefficient = 0.64). Using the heart failure classification, LVEF categories were determined by both modalities in 65.0% of patients, whereas 33.5% of patients were downward reclassified by CMR. Analysis using thresholds of 50% and 35% indicated inconsistent LVEF classification in 2.7%, 73.4%, and 63.4% of patients, respectively. Multivariate regression analysis showed that septal (odds ratio = 2.02; 95% confidence interval: 1.55 to 2.62) and lateral (odds ratio = 1.82; 95% confidence interval: 1.40 to 2.37) motion abnormalities were associated with LVEF classification differences. In conclusion, septal and lateral wall motion abnormalities detected on TTE are strong predictors of reclassification. CMR should be prioritized in such cases to guide clinical management and mitigate TTE-related misclassification risks.