Evaluation of Echocardiographic Measures of Left Ventricular Function in Patients with Duchenne Muscular Dystrophy: Assessment of Reproducibility and Comparison to Cardiac Magnetic Resonance Imaging

Abstract

Background: Patients with Duchenne muscular dystrophy (DMD) require frequent imaging to assess left ventricular (LV) function. Poor imaging windows can limit the diagnostic utility of echocardiography. Cardiac magnetic resonance imaging (CMR) is the gold standard for the assessment of LV function but has not been universally adopted in patients with DMD. The study objectives were (1) to evaluate the reproducibility of echocardiographic measures of LV function, (2) to evaluate which echocardiographic methods correlate best with CMR LV ejection fraction (LVEF), and (3) to evaluate whether CMR provides additional value compared with echocardiography.

Methods: Twenty-eight participants with DMD prospectively underwent echocardiography and CMR. Two blinded readers measured fractional shortening from M-mode and two-dimensional images and LVEF using four-chamber, biplane Simpson, 5/6 area-length, and three-dimensional methods. Speckle-tracking echocardiography was used to analyze circumferential strain. Readers subjectively rated function and segmental wall motion. Agreement was assessed using intraclass correlation coefficients, Bland-Altman plots, Spearman correlation, and weighted κ.

Results: Two-dimensional fractional shortening and 5/6 area-length LVEF had the best combination of reproducibility and correlation with CMR LVEF, though both misclassified approximately 20% as either normal or abnormal function. Other measures of LV function were less reproducible, with worse correlations with CMR LVEF. Thirty-seven percent of segments not visible on echocardiography were believed to have wall motion abnormalities by CMR.

Conclusions: Two-dimensional fractional shortening and 5/6 area-length LVEF represent the most accurate and reproducible echocardiographic measures of LV function in patients with DMD. CMR should be considered when neither of these techniques is measurable or when it is necessary to detect more subtle cardiovascular changes.

Keywords: Cardiac magnetic resonance imaging; Cardiomyopathy; Duchenne muscular dystrophy; Echocardiography; Left ventricular dysfunction.