Abstract
The pressure–volume (PV) loop illustrates the changing interaction between left ventricular (LV) pressure and volume throughout a cardiac cycle, and can be reconstructed noninvasively using either cardiac magnetic resonance (CMR) or transthoracic echocardiography (TTE). While reference values have been described, a direct comparison of PV loop parameters derived from CMR and TTE data within the same group of individuals has not been reported yet. In this study, we aimed to evaluate PV loop indices obtained by both techniques in a cohort of healthy volunteers. Twenty participants underwent cine-CMR and 2D-TTE examinations during the same seven-day period at the Heart Center UMC in Astana, Kazakhstan. Image datasets were post-processed with a dedicated software to derive conventional volumetric indices together with PV loop parameters: ventricular elastance (E es ), arterial elastance (E a ), ventriculo-arterial coupling (VAC), stroke work (SW), PV area (PVA), and work efficiency (WE). Statistical comparisons were performed with a significance threshold defined as p < 0.05; Bland–Altman plots assessed agreement. E es , E a , and VAC were significantly higher, while SW, PVA, and WE were significantly lower when derived from TTE compared to CMR. These findings were confirmed at the Bland-Altman analysis. Our findings suggest that values of PV loop parameters are different according to the imaging method, which may affect their translational potential. CMR and TTE are not interchangeable for PV loop evaluation, especially in the context of follow-up examinations.