Limitations
First, this was a single-center retrospective study with a small number
of cases. As the inherent limitation of the retrospective study, the
study protocol regarding the ablation and ATP challenge were not
consistent among the patients. For instance, one patient did not undergo
HFS (Case 1); another patient (Case 6) did not undergo repeat ATP
injection at the end of the procedure. Second, HFS was not
systematically performed in all the non-PV trigger sites. However, some
of the non-PV trigger sites, such as the Marshall tract or distal
portion of CS, might not necessarily provoke the vagal response to HFS
because of the low sensitivity of HFS and the effect of prior PV/Box
isolation on the interaction among the GPs.6, 18Third, we did not include the patients with ATP-induced frequent atrial
premature complexes.
Finally, the relationship between the episodes of AF and vagal tone
predominance was not thoroughly reviewed. Therefore, further studies are
warranted to elucidate the association between ATP-induced AF and vagal
AF.