Catheter ablation of atrial fibrillation in very young adults: a 5-year follow-up study

Abstract

Aims

Catheter ablation is an established therapy for symptomatic atrial fibrillation (AF). However, outcome data on catheter ablation for AF in young adults is scarce.

Methods and results

From 2005–2014, 85 consecutive young adults (mean age 31 ± 4 years; 69% men) with symptomatic paroxysmal AF (PAF, n = 52) and persistent (Pers) AF (n = 33) underwent pulmonary vein isolation (PVI) [±ablation of complex fractionated atrial electrograms/linear lesions in PVI non-responders] at our centre. Follow-up was based on outpatient visits including 24-h Holter-ECG at 3, 6 and, 12 months post ablation, and every 12 months thereafter. Recurrence was defined as any AF/atrial tachycardia episode >30s following a 3-month blanking period. Follow-up was available for 74/85 (87%) patients. After a median follow-up of 4.6 years (Q1: 2.6; Q3: 6.6) and a mean of 1.5 ± 0.6 (median 1, range 1-3) ablation procedures 84% [including 13% on previously ineffective antiarrhythmic drugs (AAD)] of patients were in stable SR. Single-procedural 1-year/5-year arrhythmia–free survival was 66% [95% confidence interval (CI): 56–78%]/44% (95% CI: 33–59%), respectively. Structural heart disease [SHD; hazard ratio (HR) 2.79 (95% CI 1.52–5.12), P = 0.001] and obesity [HR 1.10 (95% CI 1.00–1.21) per unit increase in body mass index >27 kg/m², P = 0.05] independently predicted AF recurrence. Major complications occurred in 6/122 (4.9%) procedures (PV stenosis in 3, cardiac tamponade in 1, stroke in 1, and arterial-venous fistula in 1).

Conclusion

In the majority of very young adults catheter ablation for AF is effective, and associated with an acceptable complication rate. SHD and obesity are predictors for AF recurrence in this population.

Introduction

Catheter ablation incorporating pulmonary vein isolation (PVI) as the procedural cornerstone is an established treatment option for symptomatic atrial fibrillation (AF). Current guidelines recommend catheter ablation for drug-refractory AF in adults, and as first-line therapy in selected patients with paroxysmal AF (PAF).¹ Our group previously reported stable sinus rhythm in 80% of patients with PAF after multiple procedures and a follow-up of 5 years on antiarrhythmic drugs.² Success rates of catheter ablation for persistent (Pers) AF are lower, and reported between 56–70% after multiple procedures and after 5 years.^3–5

However, the average age of patients in the mentioned studies was ∼60 years. In fact, data on procedural characteristics and clinical outcome of catheter ablation of AF in young adults are very limited. Two studies report on the outcome of interventional therapy for AF in patients ≤45 years of age.^6,7 Furthermore, follow-up was rather short in these studies with a maximum of 2.7 years.⁷ Thus, we sought to determine procedural characteristics, long-term clinical outcome, and predictors for AF recurrence of catheter ablation for AF in very young adults ≤ 35 years of age that were referred to our centre or catheter ablation of AF.

Methods

This is a retrospective single-centre analysis. We included all patients that received catheter ablation for symptomatic PAF or Pers AF at our hospital between 2005 and 2014, and that were ≤ 35 years of age at the time of the index ablation procedure.

PAF and Pers AF were defined according to the recommendations of the 2012 HRS/EHRA/ECAS Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation.⁸ Structural heart disease (SHD) was defined as the presence of hypertensive heart disease, coronary artery disease, cardiomyopathy and grown-up congenital heart disease, as previously described.⁹

Transoesophageal echocardiography was performed in all patients to rule out left atrial (LA) thrombus before ablation. In patients on vitamin K antagonists anticoagulation was stopped 3 days before ablation and replaced by intravenous heparin to maintain a partial thromboplastin time of 2–3 times of the normal value, or bridged with low-molecular weight heparins. From 2012, ablation was performed under therapeutic INR values of 2–3. Novel oral anticoagulants (NOAC) were stopped the day before the procedure and continued 6 h post ablation. All patients provided written informed consent. The study was approved by the local ethical board (ethical review board number: WF-016/15).

Three-dimensional electroanatomical mapping and irrigated radiofrequency ablation

Prior to PVI, we assessed for the presence of an accessory pathway (AP) and inducibility of AVNRT/AVRT in this young patient cohort. In case of AVNRT/AVRT/AP, slow pathway ablation or ablation of the AP was performed. The decision to perform additional PVI was at the discretion of the operator. Catheter ablation of AF was performed as previously reported.^10,11 In brief, mapping was performed using a 3.5-mm–tip catheter (ThermoCool Navi-Star, Biosense Webster Inc., Diamond Bar, CA). After 3D reconstruction of the LA, each PV ostium was tagged on the 3D electroanatomic map (CARTO, Biosense Webster). Patients in continuous AF underwent electrical cardioversion (CV) in order to verify PVI in SR, and PVI was reassessed in all patients after a 30-minute waiting period. If CV was successful, patients were defined as acute PVI responder. Only in cases of unsuccessful CV (PVI non-responders) further ablation was performed, as these individuals are expected to have atrial substrate beyond the PVs contributing to arrhythmia induction and maintenance. First, ablation of complex fractionated atrial electrograms (CFAE) was initiated. If AF converted to an atrial tachycardia (AT), activation/entrainment mapping was performed and linear lesion sets were placed according to the underlying tachycardia mechanism. Electrophysiological evidence of bidirectional block was obtained after cardioversion to SR, evaluated by detailed mapping and differential pacing, as previously described ¹². In patients with documented typical atrial flutter, cavotricuspid isthmus (CTI) ablation was performed leading to bidirectional block thereafter.

Cryoballoon-based pulmonary vein isolation

PVI was performed with the 28-mm cryoballoon (Arctic Front or Arctic Front Advance, Medtronic, Inc., Minneapolis, MN), as previously described.¹¹

Follow-up

Clinical follow-up was based on outpatient clinic visits including 24-h Holter ECG at 3, 6, and 12 months post ablation, and every 12 months thereafter. Last follow-up included a 24-h Holter ECG and a structured interview based on a predefined patient questionnaire. EHRA score was assessed in accordance with the European Society of Cardiology AF guidelines before the index procedure and at last follow-up.¹ Recurrence was defined as any documented AF/atrial tachycardia (AT) episode > 30 s following a 3-month blanking period. Patients without AF/AT recurrence are referred to as patients with stable SR throughout the whole manuscript.

Definition of complications

Major complications were defined as transient ischemic attack (TIA), stroke, pericardial tamponade, pneumo- or hematothorax, high-degree (> 70%) PV stenosis, arterio-venous fistula requiring intervention, or severe bleeding from the access sites or internal bleeding resulting in haemorrhagic shock. Hematoma at access sites, pericardial effusion and PV-stenosis (< 70%) were considered minor complications.

Statistical analysis

Continuous data are presented as mean ± SD or median with IQR. Categorical variables are reported as frequencies (percentages). A prognostic survival model was developed: After data reduction and imputation of missing covariables, the parameter values were estimated with the Cox proportional hazards model. The prediction model was simplified using model approximation. Thereafter the Anderson–Gill model was used to adjust the parameter estimates for within subject correlations. The regression model was presented with hazard ratios [95% confidence intervals (CI)] and P-values (Wald statistics). A generalized linear mixed model was used to evaluate differences in the EHRA score. To cope with censoring, event-free survival was estimated by Kaplan–Meier curves. All P-values are two-sided. A P-value ≤ 0.05 was considered statistically significant. The calculations were performed with the statistical analysis software R (R version 3.2.3).

Results

Patient characteristics

From 2005–2014, 85 consecutive very young adults [59/85 male (69%)] with symptomatic PAF (n = 52) or Pers AF (n = 33) underwent catheter ablation at our centre. None of the patients had long-standing (≥ 1 year) Pers AF. 11/85 (13%) patients were lost to follow-up. Final analysis was performed in 74/85 (87%) patients (PAF n = 46 [62%]; Pers AF n = 28 [38%]). Median time interval from first AF diagnosis to index ablation procedure was 2 (Q1: 0.25; Q3: 4) years. Patient characteristics are depicted in Table 1. Median patient age at the time of the index procedure was 31 years (range 19–35). The majority (65%) was between 30–35 years of age, 54% were overweight and 26% were obese [body mass index (BMI) ≥ 30 kg/m²]. There was a positive family history of AF with AF onset less than 55 years of age in a first-degree family member in 14/74 (20%) of patients. A total of 8/74 (11%) patients had underlying SHD (restrictive cardiomyopathy n = 2, non-compaction cardiomyopathy n = 1, hypertrophic cardiomyopathy n = 1, grown-up congenital heart disease n = 4); the majority of patients with SHD (n = 6, 75%) presented with Pers AF. Patients with SHD were predominantly female (n = 6), presented with lower BMI, higher CHA₂DS₂-VASc score, larger LA diameter, and lower LVEF (Table 1). Median number of antiarrhythmic drugs (AAD) prior to ablation was 1 (range 1–3). Vitamin K antagonists (n = 12) or NOAC (n = 5) were used in 17/74 (23%) of patients.

Index ablation procedure

Complete PVI by either RF (76/85; 89%) or cryoballoon (9/85; 11%) was achieved in 84/85 (99%) patients. In 12/85 (14%) patients, additional CFAE ablation (n = 4) and/or linear lesions (n = 8) was performed. CTI ablation was performed in 20/85 (24%) patients. Total fluoroscopy time was 24.1 ± 14.1 min (Table 2). AVNRT (n = 2)/AVRT (n = 1) was inducible in 3 patients followed by successful slow pathway/AP ablation, respectively. In all 3 patients, PVI was additionally performed.

Follow-up after index ablation procedure

After a median follow-up duration of 4.6 years (Q1: 2.6; Q3: 6.6) following the index procedure 37/74 (50%) patients were in stable SR (±AAD). The Kaplan–Meier estimate [including 1/37 (3%) patient that remained in SR after reinitiating previously ineffective AAD] of 1-year arrhythmia–free survival was 66% (95% CI: 56–78%) after the index procedure and the estimate of 5-year arrhythmia–free survival was 44% (95% CI: 33–59%) (Figure 1). The median event-free time after the index procedure was 3.9 years. In the subgroup of patients treated with the cryoballoon (n = 3 with PAF, n = 4 with Pers AF) during the index procedure, 1-year single procedural success was achieved in 6/7 patients (86%; 2 patients lost to follow-up). In the subgroup of patients with PAF stable SR at last follow-up after a single procedure was achieved in 54% as compared to 43% in those with Pers AF (P log-rank = 0.5).

Repeat ablation procedures

A second ablation procedure was performed in 32/74 (43%) patients, and a third procedure in 5/74 (7%) patients. PV reconduction was observed in 28/32 (88%) patients during the second, and in 2/5 (40%) patients during the third procedure. In addition to re-isolation of the affected PVs, ablation of CFAE and/or linear lesions was performed in 6/32 (19%) patients during the second and in 2/5 (40%) during the third ablation procedure. CTI ablation was performed in another 2/32 (6%) patients during the second and in 2/5 (40%) patients during the third ablation. Total fluoroscopy time during the second and third ablation procedure was 21 ± 11 min, and 16 ± 6 min, respectively. No additional ablation apart from PVI even after multiple procedures was performed in a total of 64/74 (86%) patients [42/46 (91%) patients with PAF, 22/28 (79%) patients with Pers AF].

Follow-up after repeat ablation procedures

Median follow-up duration after the last procedure was 3.4 years (Q1: 2.0; Q3: 5.2). At last follow-up, a total of 62/74 (84%) patients were in stable SR (±AAD) without AF/AT recurrence after a mean of 1.5 ± 0.6 (median 1, range 1–3) ablation procedures. When considering patients on AAD as an ablation failure, the success rate at last follow-up was 72% for the overall cohort, 76% for PAF, and 68% for Pers AF. Average number of procedures did not significantly differ between PAF and Pers AF (mean 1.5 procedures, median 1, range 1–3 vs. mean 2.0 procedures, median 1, range 1–3). The Kaplan–Meier estimate (including 8/62 (13%) patients that remained in SR after reinitiating previously ineffective AAD) of 1-year arrhythmia–free survival after the last ablation procedure was 88% (95% CI: 80–96%), the estimate of 5-year arrhythmia–free survival was 82% (95% CI: 73–92%) (Figure 1). Long-term clinical outcome did not differ between PAF and Pers AF (85% vs. 82%; P = 0.9). EHRA score significantly improved during follow-up (median of 3 before the index procedure vs. 1 at last follow-up, Δ2, P < 0.001). No patient with PAF progressed towards Pers AF. From those patients with Pers AF in whom AF/AT recurred despite multiple ablations, 3/5 (60%) patients regressed to PAF. A total of 16/74 (22%) patients were on AAD at last follow-up as compared to 43/74 (58%) patients (P < 0.001) before the index procedure. In the subgroup of patients treated with the cryoballoon during the index procedure, one patient had recurrent AF/AT that was treated by a redo PVI with RF energy, so that all 7 patients (100%) were in stable SR at last follow-up (one patient on AAD, success rate off AAD 86%).

Characteristics of patients with AF/AT recurrence

Recurrent event analysis was performed in 74 patients with follow-up. In the multivariable Cox proportional hazards model, the presence of SHD [HR 2.79 (95% CI 1.52–5.12), P = 0.001] and obesity [HR 1.10 (95% CI 1.00–1.21) per unit increase in BMI > 27 kg/m², P = 0.05] independently predicted AF/AT recurrence. Very obese patients with a BMI ≥ 35 kg/m² had a more than doubled risk [HR 2.14 (95% CI 1.00–4.60)] for AF recurrence as compared to patients with a BMI of 27 kg/m². The lowest risk for AF/AT recurrence was found in patients with a BMI between 24 and 27 kg/m², with a slightly increased risk in patients with a BMI ≤ 23 kg/m². LA diameter, the time from AF diagnosis to index ablation, arterial hypertension, a family history of AF < 55 years, and engagement in competitive sports had no independent predictive value on AF/AT recurrence.

Complications

Major complications occurred in 6/122 procedures (4.9%; significant PV stenosis n = 3, major stroke n = 1; pericardial tamponade n = 1, AV fistula requiring surgery n = 1). The major stroke occurred in a patient with restrictive cardiomyopathy 4 weeks after the index ablation procedure due to insufficient oral anticoagulation with phenprocoumon with an INR of 1.8. The patient with periprocedural pericardial tamponade was successfully treated by percutaneous pericardial drainage. Two out of three patients with significant PV stenosis (left-sided PVs) presented with dyspnoea during exercise and AF/AT recurrence. In both patients, PV-stenosis was diagnosed by PV angiography during repeat ablation. In the third patient, PV stenosis (right superior PV) was diagnosed during the index procedure. PV stenosis only occurred in patients treated by RF energy and with a LA diameter < 40 mm, and was successfully treated by dilation and drug-eluting stent implantation followed by NOAC or ASS in two patients. In one patient, PV stenting was not performed due to complete occlusion of the left superior PV. Minor complications occurred in 3/122 (2%) procedures (mild groin hematoma n = 1, mild pericardial effusion n = 2). No significant clinical predictors of periprocedural complications were identified. No death, atrioesophageal fistula or phrenic nerve palsy was observed.

Discussion

In this study, we investigated the long-term efficacy of catheter ablation of AF in very young adults. The present study of 74 patients ≤ 35 years of age undergoing catheter ablation for AF found that: (i) a beneficial long-term clinical outcome can be achieved regardless of the type of AF, with 84% (including 13% on previously ineffective AAD) of patients having stable SR after the last procedure. Single-procedural 1-year/5-year arrhythmia–free survival was 66%/44%, respectively, (ii) success rates were lower in patients with SHD and obese patients, (iii) EHRA-score significantly improved after ablation of AF, (iv) no progression from PAF to Pers AF was observed during follow-up, and (v) the rate of major complications was 4.9%.

Ablation strategy

Our ablation strategy focused on electrical isolation of the PVs. Additional ablation of CFAE or deployment of linear lesions was performed only in acute PVI non-responders, e.g. if CV failed after PVI or if AT occurred. Likewise, during repeat ablation procedures further ablation was reserved for patients presenting with durable PVI after the index procedure, for patients in AF who did not respond to CV after successful Re-PVI, or if the patient presented with AT. This approach demonstrated to be effective in previous studies from our group.^2,13,14 Furthermore, the recently published STAR AF II trial on the treatment of Pers AF demonstrated that PVI alone is non-inferior to more extensive ablation strategies, while reducing procedure and fluoroscopy times.⁴ In the present study, no additional ablation apart from PVI was performed in 86% of patients.

Clinical outcome of atrial fibrillation ablation in the very young

Most clinical studies that evaluated the success rate of catheter ablation for AF reported on a population with an average age of 60 years. After 5 years of follow-up and multiple procedures, success rates (±AAD) of up to 79.5% for PAF² and up to 70.4% for Pers AF were demonstrated.^3,5 Only two studies reported on the outcome of ablation therapy for AF in patients ≤ 45 years of age.^6,7 First, Leong-Sit et al.⁷ demonstrated AF control, defined as no or rare AF (±AAD) in 87% after a 32-months follow-up in a mixed patient cohort suffering from PAF or Pers AF (71% PAF), with repeat procedures required in 25% of patients. Later, Chun et al.⁶ reported 1-year follow-up results from the German Ablation Registry (69% PAF) with 60% of patients being free from arrhythmia recurrence (±AAD), while a repeat procedure was performed in 18% of those patients. However, data on long-term follow up in very young adults aged ≤ 35 years are scarce. Most patients in the studies by Chun et al.⁶ and Leong-Sit et al.⁷ were between 35 and 45 years of age that is why we addressed the impact of catheter ablation in a very young AF population. Furthermore, after age 35 coronary artery disease and primary systemic arterial hypertension^15,16 are becoming dominant cardiovascular risk factors that may substantially change the baseline characteristics of the population studied. After having chosen this cut-off and analysing our data, the high rate of obesity and arterial hypertension in our young AF population was somewhat unexpected.

The current study demonstrates a 5-year clinical success of 84% (±AAD) and 72% (off AAD) after multiple procedures in very young adults aged ≤ 35 years. This is in line with the findings of Leong-Sit et al.⁷ The lower success rate reported by Chun et al.⁶ may be attributed to the multi-centre study design, whereas our study reports on the outcome from a single high-volume centre. No significant difference was found difference was found in the clinical outcome of patients with PAF or Pers AF, which may be explained by the fact that in this young cohort no patient presented with long-standing Pers AF.

When compared to success rates in older patients,^2,3,5 catheter ablation of AF in very young adults appears to be associated with a more favourable outcome. As only 14% of our patients required additional ablation apart from PVI, one may hypothesize that AF in very young adults may mainly be accounted for by PV triggers and less so by degenerative LA disease. Yet, our study did not allow for specific conclusions on the reasons for this finding.

Reconnection of previously isolated PVs was suggested to be the dominant factor for arrhythmia recurrence after catheter ablation for AF.^2,17 In our study population, recovered PV conduction was present in 28/32 (88%) patients during the second, and in 2/5 (40%) patients during the third procedure. These findings are in line with previous studies,^2,17 emphasizing the need for improvement of ablation tools for durable PVI.

In the present study, two independent predictors for AF/AT recurrence could be identified. First, patients with SHD experienced a higher rate of arrhythmia recurrence. This finding coincides with the previous studies on AF.^2,3 Second, patients with an increased BMI, particularly those ≥ 35kg/m² exhibited a significantly lower success rate. Recently, risk factor control including weight management targeting a BMI of ≤ 25 kg/m² was demonstrated to improve long-term success of AF ablation, which is in line with our findings.¹⁸ The majority of very young adults with AF was overweight in our study, and 26% were obese. These findings indicate that weight management is important to reduce the incidence of AF and AF recurrence after catheter ablation also in very young patients. Of note, none of the patients who presented with AVNRT/AVRT and AF, who had successful ablation of the slow pathway/AP and PVI had AF recurrence during follow-up. This finding indicates that searching for and ablating AVNRT/AVRT in these young patients presenting with AF should be considered.

Catheter ablation of AF is known to reduce symptoms from AF and improve quality of life.^19,20 In our study, symptoms significantly improved after catheter ablation from a median EHRA score of 3 down to 1. Considering socio-economical aspects, a sub-study of the multicentre MANTRA-PAF trial randomizing patients with PAF to either first-line AF ablation or AAD therapy showed RF catheter ablation as first-line treatment to be a cost-effective strategy particularly in young patients.²¹

Complications

Previous studies reported major complications in patients undergoing catheter ablation for AF in up to 5% in a population with an average age of 60 years.^22–24 In our young patient cohort, the incidence of major complications was 4.9%, which is in line with the findings of larger studies. While vascular complications and pericardial tamponade remained rare, a relatively high incidence of significant PV stenosis was observed. Of note, all patients suffering from a relevant PV stenosis underwent RF ablation, and had a normal sized LA-diameter (< 40 mm), which may have promoted deployment of the circumferential lesion within the PVs or in close proximity to the PV ostium, although by our technique of wide-area circumferential PVI with RF energy after marking the PV-LA junction we are cautious not to ablate within the PVs. It may also be hypothesized that young patients form scar tissue more exuberantly than the elderly, which has been shown in studies on myocardial infarction.²⁵ Since data on wound healing after catheter ablation are scarce, the high rate of PV stenosis in this young population certainly deserves further investigation. We routinely perform selective PV angiography for PVI, thereby increasing the sensitivity to detect PV stenosis. Two out of three patients with PV stenosis underwent stenting and all three patients remained free from symptoms during follow-up. In any case, when doing AF ablations in younger patients, great care should be given to staying well outside of the PVs. Although patient numbers are small, this complication was not observed in the cryoballoon group. Thus, given the non-inferiority of PVI with the cryoballoon as compared to RF energy in the recent FIRE and ICE trial,²⁶ very young AF patients with normal sized LA may be particularly suitable for this technology keeping in mind the higher radiation exposure and higher incidence of phrenic nerve injuries.

When choosing the optimal therapy for very young patients presenting with symptomatic AF, the safety profile as well as the efficacy of a medical regimen vs. an interventional approach have to be taken into account. Not only has catheter ablation shown superior results in the treatment of AF regarding freedom from arrhythmia recurrence when compared to medical treatment alone, it is also associated with an overall lower rate of complications.²⁷ While interventional treatment of AF may be associated with serious side effects as stroke or cardiac tamponade, these complications showed to be rare in our cohort. The relatively high number of PV stenosis has to be addressed carefully and may potentially be avoided by special care when choosing the ablation side or by selecting the cryoballoon as a primary ablation tool. Also, as with any cardiac interventional therapy, radiation exposure due to catheter ablation should be kept to a minimum in these young patients who have a longer life-time risk of developing radiation-associated adverse events such as cancer.²⁸ On the other hand, AADs may be associated with serious side effects as well, including significant liver, kidney, thyroid and lung disease and, importantly, pro-arrhythmic effects. Especially when exposing young patients to a potentially (life) long-term drug regimen, the increased cumulative risk of side effects has to be considered. In our study, the proportion of patients on AAD was significantly reduced after catheter ablation. Most importantly, only one patient with SHD awaiting heart transplantation required amiodarone after AF ablation.

The excellent outcome data, the significant clinical improvement, potential side effects of AAD in this young population, and previously published socio-economic data support the concept of catheter ablation for AF in very young adults.

Progression and regression of atrial fibrillation

Paroxysmal AF commonly progresses to chronic forms of AF, with a progression rate ranging from 5 to 20% per year in middle-aged patients.^2,29,30 In contrast, a reduction in the rate of AF progression was reported when comparing catheter ablation to AAD therapy only. In the current study, no patient progressed from PAF to Pers AF, which was in line with a previous study showing that progression towards Pers AF from PAF is very low in young patients.³¹ Three out of five patients with Pers AF, who experienced recurrence of AF/AT despite multiple ablations regressed to PAF. Hence, even if catheter ablation proves unsuccessful in maintaining SR during long term follow up, the conversion from Pers AF to PAF may be beneficial.

Limitations

The retrospective study design did not allow for reporting separate data obtained by Kaplan–Meier analyses for outcomes of catheter ablation off AAD, since such an analysis would paradoxically yield a superior outcome of catheter ablation in patients off AAD as compared to patients on AAD, because only patients who experienced an arrhythmia recurrence were reinitiated on AAD. Furthermore, because of AF regression and symptom improvement there may be a potential for under-recognition of asymptomatic AF episodes. Ablation techniques and approaches have changed over the last decade, although PVI was the cornerstone of therapy in this study from the very beginning, and we have generally maintained our technique of PVI using 3D mapping. Yet, we adjusted our data for the effect of treatment year on outcome. Indeed, there was a trend towards improved ablation results over the years (P = 0.064). None of the patients included in this study had spontaneous non-PV triggers, thus ablation of non-PV triggers was not performed. However, we did not try to provoke non-PV triggers with adenosine and isoproterenol challenge, which is a potential limitation of this study.

Conclusions

The present study demonstrates that catheter ablation of AF in very young adults can restore SR during long-term follow-up in the majority of patients. The total procedural complication rate is acceptably low, whereas a rather high rate of PV stenosis is observed. Success rates are significantly lower in those patients with SHD or obesity. Our findings support the strategy of catheter ablation in very young adults with symptomatic AF, particularly in those without SHD.

Acknowledgements

AMS was supported by grants from the European Heart Rhythm Association and the Walter and Gertrud Siegenthaler Foundation, University of Zurich, Switzerland.

Conflicts of interest: A.M.S. received lecture honoraria and educational grants from Boston Scientific and Biosense Webster. T.M. received travel grants from 100 Biosense Webster, Cardiome and Abbott Electrophysiology. A.M. and S.M. received travel grants and lecture honoraria from Medtronic. K.H.K. received travel grants, lecture honoraria and a research grant from Medtronic. Other authors: none declared.

References

Author notes