Fig. 5

A Receiver operating characteristic analysis of global and Δglobal fractal dimension (FD) of the subacute phase for the prediction of major adverse cardiac events (MACE). The area under the curve (AUC) in the ROC analysis of global FD and Δglobal FD in the subacute phase for predicting MACE was 0.639 and 0.747, respectively. The cut-off values for global FD (1.26) and Δglobal FD (-0.009) were determined by the Youden index. B Kaplan–Meier curves for MACE based on the optimal cut-off of global FD in the subacute phase (> 1.26 versus ≤ 1.26), p = 0.006. C Kaplan–Meier curves for MACE based on the optimal cut-off of Δglobal FD in the subacute phase (> -0.009 versus ≤  -0.009), p = 0.0001