Non-invasive pressure-volume loop derived LV efficiency, contractility, and stroke work in patients with Duchenne muscular dystrophy

Early detection of left ventricular (LV) dysfunction before the onset of Duchenne muscular dystrophy–associated cardiomyopathy (DMDAC) may direct earlier clinical management. Ejection fraction (EF) is the most measured parameter. However, a decline in EF is a late finding in the assessment of heart failure. This study aims to measure non-invasive pressure-volume loop-derived ventricular efficiency, contractility , and stroke work (SW) in DMDAC patients and investigate how these measured parameters correlate with EF in patients who develop DMDAC. The current study performed a retrospective case-control study of thirty DMDAC patients who underwent two serial CMR imaging from 2016 to 2023. The patients were divided into +DMDAC and –DMDAC based on EF. Brachial pressures from cuff sphygmomanometer and CMR short axis steady-state free-precession images covering the LV were acquired, and non-invasive pressure-volume loop derived efficiency, contractility , and SW were obtained using an elastance based model. Efficiency and contractility correlated significantly (r = 0.99, p < 0.01) and (r = 0.74, p < 0.01), respectively, with EF for all subjects. Conversely, no significant correlation was found between SW and EF. Furthermore, efficiency and contractility were significantly less in the EF < 55 % group than when compared to EF ≥ 55 % (p < 0.001), but there was no significant difference in SW for both categories. Efficiency and contractility show a significant correlation with EF, with future work needed to determine if they hold prognostic information toward developing DMDAC. • DMDAC patients need better diagnostic endpoints than ejection fraction. • Energy efficiency and contractility could diagnose DMDAC patients non-invasively. • Stroke work may not be a diagnostic index for DMDAC patients. • Energy efficiency and contractility may lead to longitudinal assessment of DMDAC.