Impedance measurements as predictors of ablation lesion formation without a gap
Predictive values of impedance measurements for ablation lesion formation without a gap are compared in Figure 4. Receiver-operator characteristics curve analyses revealed that an LI drop during RFA best predicted lesion formation without a gap. A cut-off value of ≥15 ohm predicted ablation lesion formation without a gap with a sensitivity of 0.71, specificity of 0.81, and predictive accuracy of 0.75.
Ablation points with an LI drop <15 ohm had shorter RFA time (25 ± 9 vs. 27 ± 9 sec, p=0.020), higher frequency of unexpected RFA suspension (15% vs. 10%, p=0.046), and lower pre-RFA LI (104 ± 12 vs. 119 ± 15 ohm) than those with an LI drop ≥15 ohm.