6. Limitations
Several limitations of the present study warrant mention. First, LACV
measurement was done by a single medical engineer, possibly resulting in
biased data, albeit that inter-observer variability was 0.025 m/s, which
we assume to be sufficiently low. Second, the study did not investigate
data from repeat procedures, and did not examine the reconnection rate
of isolated pulmonary vein. Accordingly, AF recurrence does not
necessarily mean that the patient had an extra-pulmonary-vein AF
substrate. Third, we did not perform right atrial mapping, although the
right atrium is also thought to play a role in AF development, in some
patients at least. Fourth, AF recurrence after discharge was quantified
on the basis of intermittent short-time ECG and symptom-triggered ECG,
giving rise to the possibility that asymptomatic episodes of AF might
have been missed. Finally, the study was conducted under a single
center, observational design. Confirmation awaits a prospective
multicenter study.