4.6 Limitations 
In our study we found a significant proportion of patients with PMF after conventional proof of complete block. However, we cannot ignore the fact that there may be cases with pseudo-block without subsequent PMF recurrence, as the re-induction challenge was performed only after AT ablation and not systematically in the context of AF ablation.
Regarding patients who developed PMF after confirmation of MI block in the same procedure, the recurrence of MI conduction in an “on-off” manner probably cannot be excluded, although the pacing confirmation was always performed very close to PMF occurrence. On the other hand, patients who developed PMF in another procedure and were found from the beginning to meet the pacing criteria for MI block should confidently be considered to have MI pseudo-block.
Another limitation is that the CV measurement is governed by subjective selection of the acquired points. By taking different points for this measurement or even by shifting the timing of the isochronal scale it can lead to significant differences in the CV value. However, all these measurements were made in high-density activation maps, a fact that mitigates the subjectivity in CV evaluation. In addition, the significant difference found between PMFs with ΜΙ pseudo-block and usual PMFs that occur after AF ablation probably circumvents the above limitation.