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.