Transition of the pacing threshold
We found that 44% (4/9) of the patients in the IPT group did not have improved pacing thresholds after 3 months and required a higher pacing threshold of ≥2.0 V/0.24 msec (Figure 1). In the SPT group, the pacing thresholds for most patients improved after implantation. The pacing threshold was ≤1.0 V/0.24 msec in all cases after 3 months (Figure 2).
The ROC curves for impedance and the pacing threshold at implantation are shown in Figures 3A and 3B. The area under the curve (AUC) for impedance and pacing threshold was 0.756 (95% confidence interval [CI]: 0.586–0.926) and 0.840 (95% CI: 0.737–0.943), respectively. Comparison of the AUC for the two ROC curves showed no significant difference (P  = 0.364; Figure 3C). The cut-off values based on the ROC curve were 660 Ω for impedance and 1.0 V/0.24 msec for the pacing threshold. The sensitivity and specificity cut-off values for impedance were 100% and 66.7%, respectively, and those for the pacing threshold were 66.7% and 78.4%, respectively.