ABSTRACT
Background
Long‐standing persistent atrial fibrillation (LSPAF) is associated with adverse atrial structural and electrical remodeling, limiting the success of catheter ablation (CA).
Objective
To determine whether temporary restoration of sinus rhythm (TRSR) can improve the single procedure efficacy of CA in patients with LSPAF.
Methods
Patients with LSPAF undergoing their first CA between 2016 and 2022 were included. TRSR was attempted using cardioversion, with or without antiarrhythmic drugs (AAD), no later than 6 months before CA. The ablation strategy included pulmonary vein isolation (PVI), non‐PV trigger ablation, and linear lesions for organized atrial tachyarrhythmias (OAT). The primary study outcome was freedom from atrial arrhythmias (AA: AF and/or OAT) on/off AAD at 12 months, and the secondary outcome was freedom from AA off AAD at 12 months.
Results
One hundred eighty patients (median age 66 years, 24% female) were included. TRSR was attempted in 67 (37%) patients, and 17 (25%) of these presented in SR at the time of CA. Patients undergoing TRSR had more comorbidities (CHA2DS2‐VASc score 3.1 vs. 2.7, p = 0.012) than those who did not. The primary and secondary outcomes were significantly better in the TRSR than the no TRSR group: AA‐free survival (73% vs. 51%, p = 0.004) and AA‐free survival off AAD (69% vs. 45%, p = 0.002). The primary outcome was better in the TRSR group, whether the presenting rhythm at CA was SR or AF (75% and 72%, respectively).
Conclusions
TRSR within 6 months of CA was associated with improved arrhythmia‐free survival in LSPAF patients undergoing CA regardless of the presenting rhythm at ablation.
Keywords: atrial remodeling, catheter ablation, longstanding persistent atrial fibrillation, sinus rhythm
Atrial arrhythmia free survival following catheter ablation according to temporary restoration of sinus rhythm attempt. Abbreviation: TRSR, temporary restoration of sinus rhythm.
Abbreviations
- AA
atrial arrhythmia
- AAD
antiarrhythmic drugs
- AF
atrial fibrillation
- CTI
cavotricuspid isthmus
- IQR
interquartile range
- LA
left atrium
- LVEF
left ventricular ejection fraction
- m
months
- nTRSR
no Temporary restoration of sinus rhythm
- SR
sinus rhythm
- SVC
superior vena cava
- TRSR
temporary restoration of sinus rhythm
1. Introduction
Catheter ablation of atrial fibrillation (AF) has consistently demonstrated lower success rates in patients with non‐paroxysmal AF and especially those with long‐standing persistent (LSP) AF [1, 2, 3]. The discrepancy in success rates between different AF subtypes has been attributed to differences in the mechanism underlying the initiation and maintenance of the arrhythmia. In the initial stages of AF, triggers are believed to predominate. However, as AF becomes more established, the atria undergo adverse structural and electrical alterations that promote AF persistence. To address these remodeling effects, more extensive substrate modification approaches have been used during the ablation of non‐paroxysmal AF. These methods have not consistently improved long‐term arrhythmia outcomes beyond pulmonary vein isolation (PVI) [3, 4, 5, 6]. This suggests that empiric substrate modification may not be sufficient to address all adverse remodeling aspects found in patients with non‐paroxysmal AF.
Experimental animal studies have shown that prolonged episodes of AF alter the electrical properties of the atria, which in turn promote increased AF vulnerability and sustainability [7]. Conversely, such adverse electrical remodeling could be reversed with only a short period (1 week) of sinus rhythm maintenance [7]. In the clinical setting, restoring sinus rhythm before ablation in patients with non‐paroxysmal AF has been shown to improve arrhythmia‐free survival [8, 9, 10]. In a previous study of patients with persistent AF undergoing catheter ablation, we found that patients who underwent elective cardioversion and presented in sinus rhythm at the time of the procedure had better arrhythmia outcomes than those who presented in AF [11]. In the current study, we aim to investigate whether temporary restoration of sinus rhythm (TRSR) before the ablation procedure could similarly improve long‐term arrhythmia‐free survival in an exclusive population of patients with LSPAF undergoing their first catheter ablation.
2. Materials and Methods
The AF ablation registry at the Hospital of the University of Pennsylvania was used to identify adult individuals with LSPAF who presented for their first AF catheter ablation between January 1, 2016, and December 31, 2022. Our Institutional Review Board has approved this registry, and all patients provided written informed consent for the ablation procedure and for their data to be used for research purposes.
2.1. Study Cohort
A manual chart review was performed to identify the subtype of AF and collect clinical data elements, including demographics, pre‐ablation sinus rhythm restoration attempt, ablation procedure details, and outcomes over follow‐up. AF duration refers to the total time period of continuous, uninterrupted, ongoing AF before patients were offered rhythm control option of catheter ablation with or without an attempt at TRSR. TRSR is defined as the ability to restore sinus rhythm with cardioversion and its maintenance until the time of discharge post‐procedure. LSPAF (uninterrupted sustained AF for > 12 months duration) was defined according to the American Heart Association/American College of Cardiology/Heart Rhythm Society guidelines [12]. Patients with paroxysmal or persistent AF were excluded. Electrical cardioversion was typically attempted up to three times. The first attempt was with anterior‐posterior pad placement, the second attempt was with lateral pad placement, and the final attempt was with simultaneous use of both sets of pads. In patients willing to undergo TRSR, AAD therapy (class IC agents or pure class III agents such as dofetilide and sotalol), was initiated at the discretion of the treating physician before or at the time of electrical cardioversion. Amiodarone was not the preferred AAD, and when used, it was typically started 4–6 weeks before scheduling electrical cardioversion.
2.2. Ablation Procedure
Our AF ablation approach has been previously described [11]. Briefly, antiarrhythmic drugs (AADs) were discontinued > 5 half‐lives before ablation in all patients (except amiodarone, which was discontinued > 2 weeks before ablation). Catheters were placed in the coronary sinus and posterior right atrium. A bolus of unfractionated heparin was then administered, and heparin infusion was titrated to maintain an activated clotting time of > 350 s for the duration of the procedure. Two transseptal punctures were performed under intracardiac echocardiographic guidance, through which the ablation and multi‐electrode mapping catheters were introduced in the left atrium. Regardless of the presenting rhythm, wide‐area circumferential antral PVI was performed first, and if AF persisted, then sinus rhythm was restored by cardioversion. Following that, we performed our previously described stimulation protocol (incremental isoproterenol starting at 3 mcg and titrating to a maximum of 20–30 mcg followed by decremental overdrive pacing starting at 250 ms and decrementing to 180 ms or loss of 1:1 capture at the pacing site) and any reproducibly induced non‐PV triggers of AF were targeted. In patients with a clinical history of typical atrial flutter or in those where typical flutter was induced, CTI ablation was performed to achieve bidirectional block. Atypical flutters and other organized atrial arrhythmias (OATs) were only targeted if they were reproducibly induced and/or documented to have occurred spontaneously before the ablation procedure. In these cases, the ablation strategy was guided by activation and/or entrainment mapping using standard techniques. Any additional ablation (linear lines, empirically targeting non‐PV trigger sites, etc.) was performed based on operator preference. Acute procedural success was defined as persistent PVI (both entrance and exit block) at least 20 min after initial isolation and persistent bidirectional block across any linear lesion set.
2.3. Post Ablation Follow‐Up
Patients were discharged on an AAD at the discretion of the treating electrophysiologist. All patients were discharged on either warfarin or a direct oral anticoagulant (DOAC). All patients were also taught to do twice‐daily pulse checks to assess for asymptomatic arrhythmia recurrence. Additionally, each patient was sent home with either an insertable cardiac monitor (Medtronic LINQ), mobile cardiac outpatient telemetry (MCOT) device (Lifewatch, Rosemont, IL; CardioNet, Malvern, PA, or Medicomp Inc., Melbourne, FL) for 30 days or an extended Holter (Zio patch, iRhythm Technologies Inc., San Francisco, CA) for 14 days. After the ablation procedure, patients were seen for routine follow‐ups in the Hospital of the University of Pennsylvania outpatient clinic at around 6 weeks, 6 months, and 1 year. Beyond this period, yearly clinic visits were advised but not mandated. Routine practice at our institution is to perform MCOT or extended Holter monitoring around the 6‐month and 1‐year follow‐up appointments; additional monitors are prescribed if the patients report symptoms suggestive of arrhythmia recurrences. In the absence of documented arrhythmia recurrence, AADs were typically discontinued between 3 and 6 months postablation.
2.4. Patient Classification and Study Outcomes
The patients were classified into two groups: those who had undergone an attempt at TRSR within 6 months before the ablation and those who did not (nTRSR group). Additionally, we conducted an analysis based on the presenting rhythm at the time of ablation. The rhythm was determined based on ECG and/or intracardiac electrogram (EGM) recordings documented at the start of the case. The arrhythmia duration had to be ≥ 30 s to qualify as a recurrence. The primary study outcome was freedom from atrial arrhythmias (AF and/or organized atrial tachyarrhythmias lasting ≥ 30 s) on/off AAD at 12 months, and the secondary outcome was freedom from atrial arrhythmias off AAD at 12 months, excluding the 90‐day blanking period. We also compared the time to the first atrial arrhythmia recurrence post‐catheter ablation in both groups.
2.5. Statistical Analysis
Continuous variables are expressed as mean with standard deviation or median with the interquartile range, depending on the normality of distribution. Categorical variables are expressed as counts with percentages. The clinical data elements of different groups were compared using the χ 2 test for categorical variables and analysis of variance or the Kruskal–Wallis test for continuous variables. AF‐free survival analyses were performed using Kaplan–Meier curves. Statistical analyses were considered significant if p ≤ 0.05. Multivariate logistic regression analyses were then performed to identify significant predictors of AA‐free survival. Analyses were performed using SPSS software (version 29.0, IBM, Armonk, NY).
3. Results
Our study cohort comprised 180 patients with LSPAF who presented for their first ablation procedure. The median (IQR 25–75%) age was 67 (61–73) years, and 44 (24%) were female. There were 67 (37%) and 113 (63%) patients within the TRSR and nTRSR groups, respectively. The baseline demographics, comorbidities, and procedural details of the two groups are summarized in Table 1. Patients in the TRSR group had a higher CHA2DS2VASc score (3.1 ± 1.2 vs. 2.7 ± 1.4, p = 0.012) and were more likely to have hypertension (73% vs. 57%, P 0.027), diabetes mellitus (30% vs. 16%), and chronic kidney disease (16 (24%) vs. 7 (6%), p < 0.001). AF duration was not significantly different between the TRSR group (18 (15–24) months) and the no‐TRSR group (18 (14–34) months), p = 0.205.
Table 1.
Baseline characteristics and outcomes based on rhythm control attempt within 6 months of atrial fibrillation ablation.
| All patients (N = 180) | TRSR (N = 67) | No TRSR (N = 113) | p value | |
|---|---|---|---|---|
| Demographics and comorbidities | ||||
| Age (years), median (IQR) | 67 (61, 73) | 70 (64, 73) | 65 (61, 71) | 0.139 |
| Age ≥ 65 years | 115 (64%) | 48 (72%) | 67 (59%) | 0.095 |
| Sex | ||||
| Male, n (%) | 136 (76%) | 51 (76%) | 85 (75%) | Ref |
| Female, n (%) | 44 (24%) | 16 (24%) | 28 (25%) | 0.892 |
| AF duration (months), median (IQR) | 18 (14–30) | 18 (15–24) | 18 (14–34) | 0.204 |
| Body mass index, mean ± SD | 30 (26, 34) | 31 (27–35) | 30 (27–33) | 0.514 |
| Hypertension, n (%) | 113 (63%) | 49 (73%) | 64 (57%) | 0.027 |
| Diabetes, n (%) | 38 (21%) | 20 (30%) | 18 (16%) | 0.027 |
| Coronary artery disease, n (%) | 49 (27%) | 18 (27%) | 31 (27%) | 0.934 |
| Heart failure, n (%) | 100 (56%) | 38 (57%) | 62 (55%) | 0.809 |
| Cerebrovascular disease, n (%) | 16 (9%) | 9 (13%) | 7 (6%) | 0.099 |
| Obstructive sleep apnea, n (%) | 54 (30%) | 25 (37%) | 29 (26%) | 0.099 |
| Chronic kidney disease, n (%) | 23 (13%) | 16 (24%) | 7 (6%) | < 0.001 |
| Peripheral artery disease, n (%) | 7 (4%) | 4 (6%) | 3 (3%) | 0.266 |
| CHA2DS2‐VASc, mean ± SD | 2.9 ± 1.4 | 3.1 ± 1.2 | 2.7 ± 1.4 | 0.012 |
| Echocardiography | ||||
| LVEF (%), median (IQR) | 55 (45, 65) | 55 (45, 65) | 55 (45, 60) | 0.882 |
| Dilated left atrium, n (%) | 115 (86%) | 57 (85%) | 98 (87%) | 0.757 |
| Normal size, n (%) | 25 (14%) | 10 (15%) | 15 (13%) | 0.951 |
| Mildly dilated, n (%) | 61 (34%) | 22 (33%) | 39 (35%) | |
| Moderately dilated, n (%) | 54 (30%) | 19 (28%) | 35 (31%) | |
| Severely dilated, n (%) | 40 (22%) | 16 (24%) | 24 (21%) | |
| Procedural details | ||||
| Presenting rhythm in AF, n (%) | 163 (91%) | 50 (75%) | 113 (100%) | < 0.001 |
| Presenting rhythm in SR, n (%) | 17 (9%) | 17 (25%) | 0 (0%) | < 0.001 |
| Additional ablation, n (%) | 75 (42%) | 28 (42%) | 47 (42%) | 0.979 |
| CTI Ablation, n (%) | 37 (21%) | 15 (22%) | 22 (20%) | 0.639 |
| Posterior wall isolation, n (%) | 33 (18%) | 11 (16%) | 22 (20%) | 0.609 |
| Linear ablation sets, n (%)a | 42 (23%) | 14 (21%) | 28 (25%) | 0.552 |
| Focal atrial tachycardia | 5 (3%) | 0 (0%) | 5 (4%) | 0.081 |
| Procedural complications | 4 (2%) | 2 (3%) | 2 (2%) | 0.593 |
| Vascular complication, n (%) | 1 (1%) | 0 (0%) | 1 (1%) | |
| Pericardial effusion, n (%) | 2 (1%) | 2 (3%) | 0 (0%) | |
| Stroke, n (%) | 1 (1%) | 0 (0%) | 1 (1%) | |
| Medications at discharge | ||||
| Beta‐blocker, n (%) | 128 (71%) | 43 (64%) | 85 (75%) | 0.114 |
| Calcium channel blocker, n (%) | 21 (12%) | 6 (9%) | 15 (13%) | 0.383 |
| Digoxin, n (%) | 7 (4%) | 3 (5%) | 4 (4%) | 0.753 |
| Antiarrhythmic drug, n (%) | 113 (63%) | 51 (76%) | 62 (55%) | 0.004 |
Note: IQR refers to the 25%–75%.
Abbreviations: AF, atrial fibrillation; CTI, cavotricuspid isthmus; IQR, interquartile range; LVEF, left ventricular ejection fraction; SD, standard deviation; SR, sinus rhythm; TRSR, temporary restoration of sinus rhythm.
Includes mitral isthmus lines, superior vena cava isolation, and left atrial roof lines.
Most patients (N = 163, 91%) presented in AF at the time of ablation. This included all 113 patients from the nTRSR group and 50 patients (75%) from the TRSR group. The median time (25–75th IQR) from the attempt to restore sinus rhythm and catheter ablation was 12 [7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19] weeks, and it was comparable for patients who presented for the procedure in AF versus SR (p = 0.183). Within the TRSR group, compared to those who presented in AF, patients who presented in SR were less likely to have a history of cerebrovascular disease (8% vs. 29%, p = 0.025). There were no significant differences noted in terms of age, duration of atrial fibrillation, other comorbid conditions, or medications, including antiarrhythmic drugs.
All patients underwent PVI, and 75 (42%) had additional ablation, including cavotricuspid isthmus ablation (N = 37, 21%), posterior wall isolation (N=33, 18%), additional linear ablation sets (N = 42, 23%), and focal atrial tachycardia ablation (N = 5, 3%) (Table 1). Additional linear ablation included the mitral isthmus line and left atrial roof line. There were no differences in the rate of the additional ablation performed between the TRSR and nTRSR (Table 1). Patients in the TRSR group were more likely to be discharged on AADs (76%) than those in the nTRSR group (55%), p= 0.004. There was no difference in the other medications at discharge (Table 1).
Of the total 180 study patients, 138 (76.7%) had intermittent extended Holter and/or mobile cardiac outpatient telemetry monitoring. Only 22 patients (12.2%) who had cardiac implantable electronic devices (insertable monitors, pacemakers, or ICDs) underwent continuous monitoring. Atrial arrhythmia‐free survival at 12 months was 59% (N = 107) in the overall cohort. It was 73% (N = 49) in the TRSR cohort and 51% (N = 58) in the nTRSR cohort (p = 0.004) (Table 2). Atrial arrhythmia‐free survival off AAD was 54% (N = 97) in the overall cohort; it was 69% (N = 46) in the TRSR cohort and 51% (N = 51) in the nTRSR cohort (p = 0.002). AADs were discontinued at a median (IQR) of 6 (4) months, and this was not statistically different (p = 0.10) between the TRSR (median 6, IQR 4 months) and nTRSR (median 6, IQR 3 months). There was no difference in the primary and secondary outcomes in patients within the TRSR group that presented in AF or SR at the time of the ablation procedure (Supporting Information S1: Table 2). These differences in the primary and secondary outcomes between groups were also seen on the KM survival curves (Graphical Abstract and Figure 1). The median (25%–75% IQR) time to arrhythmia recurrence was 4 (3–5) months in the overall cohort. It was 5 (3–7) months in the TRSR cohort and 4 (3–5) months in the nTRSR cohort (p = 0.214). On multivariate analysis, TRSR continued to be significantly and independently associated with the primary outcome despite controlling for other factors such as AADs on discharge, age ≥ 65 years, hypertension, diabetes mellitus, obstructive sleep apnea, and chronic kidney disease (Table 3).
Table 2.
Primary and secondary outcomes based on rhythm control attempt within 6 months of atrial fibrillation ablation.
| Outcomes | All patients (N = 180) | TRSR (N = 67) | No TRSR (N = 113) | p value |
|---|---|---|---|---|
| Atrial arrhythmia‐free survival, n (%) | 107 (59%) | 49 (73%) | 58 (51%) | 0.004 |
| Time to recurrence, median (IQR) | 4 (3–5) | 5 (3–7) | 4 (3–5) | 0.214 |
| Atrial arrhythmia‐free survival off AAD, n (%) | 97 (54%) | 46 (69%) | 51 (51%) | 0.002 |
Note: IQR refers to the 25%–75% interquartile range.
Abbreviations: AAD, antiarrhythmic drugs; IQR, interquartile range; TRSR, temporary restoration of sinus rhythm.
Figure 1.
Atrial arrhythmia free survival following catheter ablation according to temporary restoration of sinus rhythm attempt and rhythm at presentation. AF, atrial fibrillation; SR, sinus rhythm; TRSR, temporary restoration of sinus rhythm.
Table 3.
Predictors of atrial arrhythmia‐free survival 1 year after multivariate regression using patient risk factors and procedural data.
| Variables | Odds ratio (95% CI) | p value |
|---|---|---|
| TRSR within 6 months | 2.90 (1.47–5.70) | 0.00 |
| Age ≥ 65 years | 0.82 (0.43–1.58) | 0.56 |
| Antiarrhythmic drug on discharge | 1.01 (0.52–1.96) | 0.99 |
| Diabetes mellitus | 0.80 (0.36–1.76) | 0.57 |
| Hypertension | 1.00 (0.52–1.92) | 0.99 |
| Obstructive sleep apnea | 0.48 (0.24–0.95) | 0.04 |
| Chronic kidney disease | 0.46 (0.17–1.22) | 0.12 |
| LA size (normal) | Reference | Reference |
| Mildly dilated | 1.47 (0.54–4.01) | 0.42 |
| Moderately dilated | 1.27 (0.46–3.51) | 0.63 |
| Severely dilated | 0.84 (0.29–2.43) | 0.76 |
Note: Variables controlled for TRSR within 6 months, antiarrhythmic drug on discharge, age ≥ 65 years, hypertension, diabetes mellitus, obstructive sleep apnea, chronic kidney disease, and left atrial size.
Abbreviations: CI, confidence interval; TRSR, temporary restoration of sinus rhythm.
At the time of attempted TRSR, 67 patients (37%) were not on any AAD. Amiodarone was used in 23 patients (13%). Among class III agents other than amiodarone, dofetilide was used in 62 patients (34%) and sotalol in 5 patients (2.8%). Among class I agents, flecainide was used in 13 patients (7%) and propafenone in 9 patients (5.0%). Dronedarone was used in one patient (1%). Amiodarone use was similar between groups (10 patients (TRSR) vs. 13 patients (no‐TRSR), p = ns).
4. Discussion
This study of patients with LSPAF undergoing initial catheter ablation demonstrated improved long‐term arrhythmia outcomes when an attempt to restore sinus rhythm was made within 6 months before the procedure. The benefits of sinus rhythm restoration were seen regardless of the presenting rhythm at the time of ablation. These findings suggest that restoration of sinus rhythm, even if temporary, may be used as a complementary strategy to improve long‐term maintenance of sinus rhythm in patients with LSPAF undergoing catheter ablation.
It has been consistently demonstrated that patients with paroxysmal AF achieve better success rates after catheter ablation than those with non‐paroxysmal AF [13, 14, 15]. The difference in success rates is attributed to distinct arrhythmia mechanisms underlying AF in the latter group. Many investigators hypothesize that patients with non‐paroxysmal AF have substrate abnormalities, and so have utilized extensive ablation beyond PVI to address this. However, the effectiveness of extensive ablation strategies has not consistently surpassed PVI [5, 6, 16]. This suggests that empiric substrate modification may not be sufficient to address the mechanisms at play in non‐paroxysmal AF. Previous studies have shown adverse electrical remodeling in persistent AF, such as maladaptation of atrial refractory periods, can lead to regional heterogeneity in activation patterns that may increase overall AF vulnerability [7, 8, 17, 18, 19]. Conversely, the transition from persistent to paroxysmal AF has been shown to improve overall bipolar voltage in the LA and decrease total LA volume [20]. It has also been found that among AF patients, an increased duration of time in sinus rhythm leads to favorable structural remodeling in both the LA and left ventricle [21, 22, 23, 24]. Such favorable electrical and structural remodeling may improve the overall success of catheter ablation in patients with non‐paroxysmal AF. In an earlier study, we showed that restoration and maintenance of sinus rhythm improved long‐term arrhythmia outcomes in patients with persistent AF undergoing catheter ablation. In this study, we extend those observations to an exclusive group of patients with LSPAF. This population cohort has been found to have the worst outcomes after catheter ablation. We found that, similar to our previous experience in patients with persistent AF, those with LSPAF also had improved ablation outcomes after restoration of sinus rhythm. Interestingly, long‐term arrhythmia outcomes were improved despite a greater comorbidity burden (higher CHA2DS2‐VASc score) in the TRSR compared to the nTRSR group. Also, patients within the TRSR had higher arrhythmia‐free survival regardless of whether they presented in AF or SR at the time of AF ablation. We attribute these observations to the favorable effects of sinus rhythm reversing adverse atrial remodeling associated with non‐paroxysmal AF. However, due to our study's retrospective observational nature, we could not assess these remodeling changes objectively, and other unmeasured bias may not be fully accounted for. Nevertheless, our observations add to the existing literature on the benefits of restoring sinus rhythm for improving catheter ablation outcomes in patients with non‐paroxysmal AF, including those with LSPAF.
In our study, patients in the TRSR group (76%) were more likely to be discharged on AAD than those in the nTRSR group (55%), and this difference was statistically significant (p = 0.004). This finding is likely due to our institution's practice of temporarily continuing previously initiated AADs after the ablation procedure, particularly in patients with non‐paroxysmal AF. This practice is supported by a prior study by our group (5A Study [see 25, 26]) that showed AAD treatment during the first 6 weeks after AF ablation reduced the need for cardioversion/hospitalization for arrhythmia management within the first 6 weeks after AAD initiation and long‐term arrhythmia recurrences [25, 26]. It is, however, important to note that in the current study, patients in the TRSR group had a higher 1 year AA‐free survival off AAD (secondary outcome, Table 2) and that AAD at discharge was not associated with AA‐free survival at 1 year (Supporting Information S1: Table 1). This latter point is consistent with the observations of the previously conducted 5A Study [26]. It also aligns with the lack of association between AAD at discharge and our primary outcome (Table 1). In the multivariate analysis, temporary restoration of sinus rhythm was the only variable associated with the primary and secondary outcomes (Table 3). Although we hypothesize that the benefits of sinus rhythm restoration improved catheter ablation outcomes through favorable electrical and structural remodeling, it is possible that the ability to maintain sinus rhythm in these patients could indicate a more favorable atrial substrate at baseline [27]. Regardless of the underlying mechanism, our approach may help identify a subgroup of LSPAF patients who are more likely to benefit from catheter ablation [28]. In that context, it is worth noting that within the TRSR group, patients who maintained sinus rhythm until the time of ablation had a trend towards better outcomes than those who presented in AF. Interestingly, patients in the TRSR group who presented for the ablation in sinus rhythm had a relatively shorter interval between the attempt to restore sinus rhythm and the procedure (median of 10 weeks vs. 14 weeks for those who presented in AF). These observations would favor attempting sinus rhythm restoration closer to the ablation procedure or incorporating additional attempts at sinus rhythm restoration in subjects who experience AF recurrence after the initial attempt.
4.1. Limitations
Our study has several limitations. This was a single‐center, retrospective, observational, and nonrandomized experience. As with every retrospective cohort, selection bias is inherent, and in our study, patients referred for ablation may represent a subgroup with shorter continuous AF duration or different clinical profiles. Additionally, the duration of sinus rhythm maintenance after cardioversion was not systematically monitored. Also, the sample size was relatively small. Additionally, most patients were monitored with mobile cardiac outpatient telemetry (MCOT) or extended Holter monitors, and only a minority (12%) had cardiac implantable electronic devices (insertable monitors, pacemakers, or ICDs). Thus, there was a lack of consistent, continuous monitoring in our study cohort, which prohibits us from assessing the impact of TRSR on arrhythmia burden after catheter ablation. Since we did not mandate pre‐ablation monitoring, we could not accurately assess the duration of sinus rhythm after cardioversion and, therefore, can not provide data on the optimal duration of pre‐ablation sinus rhythm maintenance for improving catheter ablation outcomes in these patients. Lastly, we did not consistently assess for atrial voltage abnormalities in these patients and so are unable to provide data on the underlying atrial substrate.
5. Conclusions
Our study shows that pre‐ablation restoration of sinus rhythm is associated with improved single‐procedure efficacy of catheter ablation in patients with long‐standing persistent AF. While the long‐term arrhythmia outcomes were most favorable for patients who remained in sinus rhythm leading up to the ablation procedure, they were also improved in patients in whom AF recurred pre‐ablation. These observations support utilizing temporary restoration of sinus rhythm as a strategy to improve catheter ablation outcomes in patients with LSPAF.
Disclosure
The authors have nothing to report.
Consent
Patient consent was not required for this study per IRB protocol.
Conflicts of Interest
The authors declare no conflicts of interest.
Supporting information
LSPAF TRSR Tables.
Data Availability Statement
The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
LSPAF TRSR Tables.
Data Availability Statement
The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.