3.5 Electrophysiological findings in repeat ablation sessions
The LRAF group consisted of 151 patients (23.9%) and repeat ablation
sessions were performed in 76 patients in the LRAF group (50.3%). The
average duration from the 1st session to the repeat ablation session was
8.6±7.1 months. A reconnection of any of the PVs was identified in 55 of
76 patients (72.4%). No significant difference was observed in the ΔNLR
between the patients without a PV reconnection and those with a PV
reconnection (1.120±1.323 vs 1.880±3.234, p=0.302, Figure 2A). However,
the ΔNLR was significantly higher in the patients with a right PV
reconnection than in those without a right PV reconnection (0.914±1.199
vs 2.316±3.615, p=0.032, Figure 2B). No significant difference was
observed in the ΔPLR between the patients without a PV reconnection and
those with a PV reconnection (8.233±45.00 vs 21.84±74.11, p=0.434,
Figure 2C). No significant difference was observed in the ΔPLR between
the patients with a right PV reconnection and those without a right PV
reconnection (10.20±36.54 vs 24.82±85.21, p=0.349, Figure 2D).
In 55 patients, 1 PV, 2PV, 3PV, and 4PV reconnections in repeat ablation
sessions were detected in 12, 23, 7, and 13 patients, respectively.
There was a tendency for the ΔNLR to increase as the number of
reconnected PVs increased, but there was no significant difference in
the ΔNLR between the two groups (Figure 3).
DISCUSSION
The present study highlighted the following results. (1) Higher NLR and
PLR changes were associated with a late recurrence of AF/AT after the
PVI. (2) An NLR change was significantly higher in the patients with
right PV reconnections than in those without right PV reconnections.
Radiofrequency catheter ablation of atrial arrhythmias is known to cause
an increase in various markers of inflammation and myocardial
injury.19-20 Infiltration of inflammatory cytokines
(IL-1, IL-8, TNF-α) into myocardial injury sites induces hematopoietic
factors.21-22 These factors stimulate hematopoiesis of
neutrophils in bone marrow and a rapid supply of neutrophils from the
bone marrow pool. Although segmented cells are the main neutrophils in
peripheral blood, in an inflammatory status, the number of stab cells
and metamyelocytes increases. Increasing the number of neutrophils also
leads to an enhancement in the blood viscosity and hypercoagulability by
causing an interaction in the platelets and
endothelium.23 Neutrophils suggest nonspecific
inflammation and the decrease in the number of lymphocytes reflects the
inflammation.24 Low lymphocyte counts have been
reported to be related to inflammation.25 The NLR,
therefore, more effectively reveals inflammation than the neutrophil
count.23 The NLR is a powerful independent indicator
of a prognosis in systemic inflammation, atherosclerotic heart disease,
and cancer patients.26-27 The PLR is an easy to
perform blood test associated with a poor prognosis when elevated in
patients suffering from various oncologic
disorders.28-29 The PLR is also a strong independent
indicator of a prognosis in systemic inflammation such as in critical
limb ischemia and collagen disease.30-31
A previous study demonstrated that inflammation was increasingly
recognized to play a significant role in the genesis and perpetuation of
AF.32-33 Koyama et al. reported an immediate AF
recurrence is closely associated with an acute inflammatory process and
over 70% of patients with an early AF recurrence have AF episodes 3
months after ablation.11 The relationship between an
ERAF and LRAF remains unclear, but several reports have shown the
relationship between an ERAF and the durability of the PVI34, and overt ERAFs require the reconnection of a
critical number of fibers at the level of the PV-LA
junction.35 Probably the reconnection of the left
atrium and PVs, presence of non-PV foci triggering AF, and other
mechanisms might be associated with LRAFs, but according to the
relationship between an ERAF and LRAF, an acute inflammatory response
after a PVI is one of the most important risk factors for an LRAF. In
our study, the ΔNLR and ΔPLR were higher in patients with an ERAF than
in the no-ERAF group, and as a result, the mechanism of the ERAF was
possibly associated with an inflammatory process. We also demonstrated
that the ΔNLR was higher in patients with a right PV reconnection than
in those without a right PV reconnection (0.914±1.199 vs 2.316±3.615,
p=0.032, Figure 2B). Recent reports have shown that patients with an
ERAF have a significantly higher rate of PV reconnections, in particular
of right PV reconnections (82.5% vs 29.2%).35 They
also showed that a higher number of right PVI segments with
reconnections were observed in those with an ERAF as compared to those
without. It is unclear why the right PV reconnections were associated
with ERAFs. Presently it remains unclear whether a durable right PV
isolation will positively impact the ERAF expression and long-term
outcomes. A hypothesis to explain this result is that radiofrequency
current is delivered with a high power on the right PV anterior line,
which has a thick wall and the posterior line consisting of fiber
bundles, while the radiofrequency current is limited on the left
posterior line near the esophagus.
In the LRAF group, the ratio of persistent AF (PerAF) patients was
significantly higher than that in the no-LRAF group. The plasma BNP
level was also significantly higher in the LRAF group than no-LRAF
group. Generally the left atrium in PerAF patients causes structural and
electrical remodeling and a progressive pressure overload. The level of
inflammatory cytokines in heart failure patients was significantly
higher than that in patients with a normal heart, but in this study
there were no significant differences in the WBCs, hs-CRP, or NLR levels
before the ablation between the PAF and PerAF patients. These levels
after the ablation and changes from before to after the ablation were
similar between the PAF and PerAF patients. These results indicated that
the difference between PAF and PerAF did not affect the inflammatory
status during the acute phase of the ablation. In the LRAF group, the
ratio of a non-PV trigger ablation and an AT ablation was higher than
that in the no-LRAF group due to more PerAF patients in the recurrence
group, but the total number of energy applications did not differ the
between the two groups. A variation was observed in the period from the
initial to repeat ablation session (8.6±7.1 months), but this also did
not differ between the two groups.
The NLR and PLR can be easily calculated by dividing the neutrophil and
platelet counts by the number of lymphocytes, respectively. These
measurements are a simple, cost-effective routine test. As suggested by
many studies, they may emerge as markers of inflammatory conditions and
disease activity. In the present study we demonstrated the relationship
between the ERAF/LRAF and ΔNLR/ΔPLR, suggesting an inflammation status.
Further studies on inflammation after the PVI and AF recurrence and PV
reconnections may be necessary in the future.
CONCLUSION
The NLR and PLR changes were significantly related to early and late
recurrences of AF/AT after the PVI. A greater NLR change was
significantly associated with a right PV reconnection in the repeat
ablation session.