Introduction
As the most common sustained supraventricular arrhythmia, atrial
fibrillation (AF) exists in more than 1% of the general population,
becoming a crucial heath issue with life expectancy increasing,
especially in North America and Europe.1 Most patients
with symptomatic AF have impaired quality of life, together with
psychological disorders, such as depression and
anxiety.2 Furthermore, the older AF patients are at
the higher risk of thromboembolism, heart failure, and dementia,
contributing to increased mortality.3
Among multiple treatment strategies for AF, it is catheter ablation (CA)
that predominantly isolates the pulmonary veins (PVs) via various energy
sources and technologies, or in combination with patient-specific
additional ablation.4 CA is a well-recognized
treatment alternative for restoring and maintaining sinus rhythm due to
interruption of arrhythmogenic pathways in the atrial substrate,
elimination of the foci initiating AF, and modulation of cardiac
autonomic innervation.5,6 Nevertheless, there are
still more than 20% ablation-treated patients with paroxysmal AF
suffering from arrhythmia recurrence, and the efficacy of CA on
persistent AF is inferior to that on paroxysmal AF.7,8The underlying mechanisms of early recurrence within the first 3 months
post-ablation are more likely to be related to temporary local
inflammation, the formation of inhomogeneous scar tissue, and transient
imbalances of autonomic activity.9,10 Regarding to
late recurrence occurring after a 3-month blanking period, one of the
most prominent reasons is reconnection of isolated PVs that is also
associated with cardiac parasympathetic
hypertonicity.11,12
Deceleration capacity (DC), an index assessing deceleration-related
heart-rate variability (HRV), is usually regarded as an indicator of
parasympathetic activity when calculated in accordance with
phase-rectified signal averaging (PRSA) algorithm.13Owing to elimination of non-periodic components in a 24-hour Holter
recording, DC is rarely affected by ectopic beats and artifacts, which
is superior to the established HRV parameters. DC, initially designed
for predicting cardiac mortality in post-infarction patients, was
subsequently reported to have no connection with AF recurrence after
circumferential or segmental PV isolation.14,15 Recent
studies, however, have showed that DC was probably related to AF
prognosis in ablation-treated patients.16,17Therefore, this systematic review and meta-analysis was performed for
the purpose of investigating the relationship between DC and AF
recurrence following ablation and evaluating the prognostic
value of DC in ablation-treated
patients.
Methods
This study was registered in the International Prospective Register of
Systematic Reviews (PROSPERO; registration number CRD42023475061), which
was subsequently administered as per the Preferred Reporting Items for
Systematic Reviews and Meta-analyses (PRISMA) and the Meta-analysis of
Observational Studies in Epidemiology (MOOSE).18,19
Search strategy
A literature search was systematically carried out in the Embase,
PubMed, Web of Science, China National Knowledge Infrastructure (CNKI),
and Wanfang databases from their inception until October 01, 2023. A
synthesis of search keywords was mainly in relation to “deceleration
capacity”, “vagal”, “parasympathetic”, “sympathetic”,
“autonomic”, together with “atrial fibrillation” and “ablation”.
There was no restriction on language. The bibliographies of relevant
studies were manually searched to verify additional articles as well.
Eligibility criteria
The studies were included when fulfilling the following criteria: (1)
retrospective or prospective observational studies; (2) ablation-treated
participants with and without AF recurrence; (3)
either the pre- and post-ablation
data on DC in both recurrence and non-recurrence groups, or the ratios
based on DC for predicting AF recurrence were available. There was no
limitation on follow-up duration or sample size. The studies would be
excluded if (1) they were case reports, reviews, dissertations, or
duplicates; (2) they were only involving DC prior to ablation; (3) the
data on DC was insufficient; (4) the full text couldn’t be retrieved.
After removing the duplicates, two reviewers (PKZT, LZH) independently
screened the title and abstract of all the retrieved literature to
exclude the irrelevant studies that didn’t contain the information on
AF, DC and ablation. The remaining studies following the preliminary
screening were assessed for eligibility based on full-text review.
Ambiguities were addressed by consulting with a third author (CAY). The
process of study selection was illustrated in Figure 1.