3.2 Comparisons of DC in patients with and without AF
recurrence
A total of 7 studies reported the data on DC prior to ablation, and the
pooled mean difference estimated with the random-effect model between
recurrence and non-recurrence groups was not statistically significant
(Figure 2A; WMD, 0.34; 95%CI, -0.12 to 0.79; P = .15),
suggesting the comparability of DC was achieved at baseline. Similar
results were retrieved in the sensitivity analysis (Supplement 1A).
The data on DC within 3 days
post-ablation were reported in 6 studies involving 748 subjects. The
pooled mean difference assessed with the random-effect model was 1.0
(Figure 2B; 95%CI, 0.33 to 1.67; P < .01), indicating
that patients with AF recurrence had the higher DC within 3 days
post-ablation in relation to those without AF recurrence. Since
significant heterogeneity was observed between these studies
(I 2 = 97.5%, P < .01), the
subgroup analysis was performed in accordance with the periods of AF
recurrence. The pooled mean difference in DC between ablation-treated
patients with and without late recurrence was 0.71 (95%CI, 0.53 to
0.88; P < .01) with marginal heterogeneity
(I 2 = 0.0%, P = .83). The higher mean
difference between participants with and without early recurrence was
observed despite only one study (WMD, 2.6; 95%CI, 2.4 to 2.8; P< .01). In the sensitivity analysis, it was also suggested
that the severe heterogeneity was associated with the study involving
ablation-treated patients with early recurrence (Supplement 1B).
There were 4 studies involving the DC data on ablation-treated patients
after 3 months of follow-up. The pooled mean difference estimated with
the fixed-effect model was 1.54 (Figure 2C; 95%CI, 1.11 to 1.96;P < .01) with limited heterogeneity
(I 2 = 48.4%, P = .12), indicating that
the higher DC after 3 months post-ablation was observed in patients with
late recurrence compared to those without recurrence. In the sensitivity
analysis, the results were similar
(Supplement 1C). Publication bias was
illustrated with funnel plots (Supplement 2).
Two studies reported the DC data on AF patients after 6 months of
follow-up, and the results were controversial. DC was higher in
radiofrequency-ablation-treated patients with AF recurrence compared to
those without recurrence (5.89 ± 1.65 ms vs 3.97 ± 0.98 ms, P< .05), whereas there was no significant difference between
cryoballoon-ablation-treated patients with and without AF recurrence
(3.7 ± 1.1 ms vs 3.8 ± 1.6 ms).17,23 Changes in DC
among patients with and without AF recurrence were illustrated in Figure
3.