NPPB and amyloidosis: The DPD retention index showed significant, albeit weak to modest, correlations with LV global longitudinal strain (LV-GLS: r = 0.366, P < 0.001), right ventricular free wall longitudinal strain (RV-FW-LS: r = 0.316, P = 0.002), LV diastolic function (E/e′ average: r = 0.304, P = 0.013), NT-proBNP (r = 0.332, P < 0.001), troponin T (r = 0.233, P = 0.022), 6 min walk distance (6MWD: r = −0.222, P = 0.033), and National Amyloidosis Centre (NAC) stage (r = 0.294, P = 0.003).