Limitation
There were several limitations to our study. First, this is a study with
a small number of patients. Second, it is possible that the LVA and ACZ
varied with heart rate or pacing site. Atrial tachyarrhythmias occur by
premature atrial beat during sinus rhythm where electrical activity
originating from the sinus node spreads towards the superior vena cava
and right atrial appendage. Moreover, a previous study reported that LA
activation pattern did not differ regardless of site of earliest LA
breakthrough.15 Hence, using LA activation during high
right atrial pacing is acceptable. Third, our study completed 3-D
mapping after the PV isolation. Fourth, there was no control group in
our study. To evaluate our hypothesis, a control group is crucially
important. Lastly, the criteria for defining the ACZ was different from
previous studies.