GH after ablation
GH occurs as an adverse event of catheter ablation for AF due to thermal
injury of the periesophageal nerves close to the
LAPW.7 Yamasaki et al.18 reported
excessive transmural injury in 5.8% of patients who underwent AF
ablation using an RF catheter with additional LA roof line ablation,
noting that body mass index may be a predictor of excessive transmural
injury after ablation.
The prevalence of GH after CBA is reported to be
10.3–17.5%.7,11 Aksu et al.7 found
that the prevalence of GH was higher in the CBA group; however, GH was
generally reversible after CBA, compared with RF ablation, and the nadir
temperature during CBA for inferior PVs and smaller LAD was associated
with GH in the CBA group. Miyazaki et al.11demonstrated that GH after CBA occurred in cases in which the esophagus
was located between the LAPW and thoracic spine, or in those in which
the distance between the RIPV and esophagus was short. In our study, CBA
of the LA roof was performed in addition to PVI; however, the prevalence
of GH after ablation was not as high as previously reported. This result
may be attributed to the therapeutic strategy of avoiding the ablation
of the LAPW such as the LAPW bottom line. In our study, LAD was
significantly smaller in patients with GH, as previously reported. Given
that RIPV diameter was also smaller in those with GH, a cryoballoon may
be apt to contact the broader area of the LAPW during PVI, which may
cause periesophageal nerve injury. However, our multivariate analysis
indicated that LA roof height from the point of contact between the LAPW
and esophagus can predict GH after CBA. During CBA of the LA roof, the
cryoballoon contacts both the LA roof and part of the LAPW; namely,
cryothermal energy conducts the LAPW close to the esophagus, especially
in patients with lower LA roof height. This may explain the findings
predictive of GH in our study.
Several studies have also examined the relationship between LET and
esophageal complications. Kuwahara et al.5 reported
that RF applications under LET monitoring may reduce the incidence of
GH; indeed, conventional PVI using an RF catheter is generally performed
under LET monitoring. Additionally, Fürnkranz et al.4demonstrated that LET-guided CBA with a cutoff value of 15°C was
associated with a lower incidence of esophageal lesions. In contrast,
Miyazaki et al.11 reported that LET monitoring was not
related to the incidence of esophageal complications after CBA for PVI;
instead, the incidence of esophageal lesions increased when an
esophageal probe was used.
In this study, we performed CBA under LET monitoring. First, although
CBA of the LA roof was additionally performed, LET reached 15°C most
frequently during PVI. Second, although no significant difference was
observed, the percentage of patients in whom LET reached 15°C,
especially during LA roof line ablation, was higher in those with GH
than in those without. Moreover, LET during CBA of the LA roof reached
15°C more frequently when LA roof height was lower, or when the distance
between the LA roof and esophagus was shorter. If CBA were performed
without LET monitoring, the incidence of GH may have differed.
Although GH is detected via esophagogastroscopy in patients undergoing
catheter ablation for AF, not all cases are symptomatic. Hasegawa et
al.8 reported that the incidence of symptomatic GH
after CBA for PVI was 3.0%; however, as the degree of symptoms
associated with GH may be slight in some cases, the incidence of
symptomatic GH may be underestimated.
Lakkireddy et al.6 reported that mean PAGI-SYM scores
significantly increased from 7.8% to 15.6% 24 hours after ablation,
with higher scores in patients with abnormal gastrointestinal functional
test results. In our study, PAGI-SYM scores did not increase 1 day after
ablation; however, they significantly increased 1 week after ablation in
patients with GH. Although the scores were lower in our study than
previously reported, patients may suffer from mild GH-related symptoms
that appear a while after ablation.