4 DISCUSSION
The major finding of this study was that in cases wherein CB ablation of the superior PVs was unable to isolate the PVs, the CST ablation technique was highly successful if CB ablation of the superior PVs met the following two criteria: NT ≤-46°C and complete occlusion of the superior PVs. Furthermore, the CST ablation technique was mostly ineffective in cases wherein these two criteria were not met.