Pulmonary vein (PV) automaticity is an established trigger for paroxysmal atrial fibrillation (PAF), making PV isolation (PVI) the cornerstone of catheter ablation. However, data on triggers for atrial fibrillation (AF) and catheter ablation strategy in very young patients aged <30 years are sparse. A total of 51 young patients (mean age 24.0 ± 4.2 years, 78.4% men) with drug-refractory PAF underwent electrophysiology (EP) study and ablation at 5 EP centers. None of the patients had structural heart disease or family history of AF. EP study induced supraventricular tachycardia (SVT) in 12 patients (n = 12, 23.5%): concealed accessory pathway mediated orthodromic atrioventricular reentrant tachycardia in 3 patients, typical atrioventricular nodal reentrant tachycardia in 6 patients, left superior PV tachycardia in 1 patient, left atrial appendage tachycardia in 1 patient, and typical atrial flutter in 1 patient. In patients with induced SVTs, SVT ablation without PVI was performed as an index procedure, except for the patient with atrial flutter who received cavotricuspid isthmus ablation in addition to PVI. Remaining patients underwent radiofrequency (n = 15, 29.4%) or second-generation cryoballoon-based PVI (n = 24, 47%). There were no major complications related to ablation procedures. Follow-up was based on outpatient visits including 24-hour Holter-electrocardiogram at 3, 6, and 12 months after ablation, or additional Holter-electrocardiogram was ordered in case of symptoms suggesting recurrence. Recurrence was defined as any atrial tachyarrhythmia (ATA) episode >30 seconds after a 3-month blanking period. A total of 2 patients with atrioventricular nodal reentrant tachycardia, 1 with left atrial appendage tachycardia, experienced AF recurrence within the first 3 months and received PVI. After the 3-month blanking period, during a median follow-up of 17.0 ± 10.1 months, 44 of 51 patients (86.2%) were free of ATA recurrence. In the PVI group, 33 of 39 patients (84.6%) experienced no ATA recurrence. In conclusion, SVT substrate is identified in around a quarter of young adult patients with history of AF, and targeted ablation without PVI may be sufficient in the majority of these patients. PVI is needed in the majority and is safe and effective in this population.
Atrial fibrillation (AF) is the most common arrhythmia in adults. The prevalence of AF increases with age, from 0.5% of population <40 years to 5% for patients >65 years and approximately 10% prevalence among octogenarians. Current guidelines recommend pulmonary vein (PV) isolation (PVI)–based catheter ablation for patients with drug-refractory symptomatic AF, and as a first-line therapy in selected patients with paroxysmal AF (PAF). The average age of patients in the AF ablation studies is approximately 60 years, , and data on procedural characteristics and clinical outcome of catheter ablation in very young adults are very limited. Studies in patients with AF <35 years included heterogeneous group of both patients with PAF and persistent AF with PVI-based ablation strategies. , However, data on specific AF triggers, procedural safety profile, and stepwise ablation technique for very young patients ≤30 years old are sparse. In the present study, we aimed to identify the mechanism of AF, procedural safety and efficacy, and outcome in very young AF patients ≤30 years of age referred to ablation.
Methods
This is a retrospective analysis from pooled data from 5 electrophysiology (EP) centers (1 in Germany, 1 in the United Kingdom, and 3 in Turkey) of patients ≤30 years of age who underwent EP study and ablation for PAF between January 2015 and September 2020. PAF was defined as AF that terminates spontaneously or with intervention within 7 days of onset. Patients with previously documented regular supraventricular tachycardia (SVT) were excluded. All patients underwent transthoracic echocardiography before ablation to assess structural abnormality, left ventricular ejection fraction, left atrial (LA) diameter, and valvular disease. Transesophageal echocardiography was performed to rule out the presence of LA thrombus on the same day or the day before the procedure. No additional preprocedural imaging was performed. Patients were anticoagulated in accordance with current guidelines. Patients with LA thrombus, uncontrolled thyroid dysfunction, contraindication to anticoagulation, pregnancy, previous AF ablation, severe valvular disease, and an LA size >60 mm were excluded. Severity of symptoms was recorded according to the European Heart Rhythm Association score. Patient demographics and procedural data were collected prospectively; these were extracted, collated, and analyzed retrospectively from institutional board–approved registries and anonymized online patient databases. Patients gave written informed consent before their procedures, and the study was conducted in alignment with ethical standards described in the Declaration of Helsinki.
A full EP study was performed in all patients before PVI, using catheters placed at the His, inside the coronary sinus, and the right ventricular apex. Patients were assessed for the presence of a concealed accessory pathway (AP) and inducibility of regular SVT, including administration of isoprenaline. If a regular SVT was induced, catheter ablation for SVT was performed with no additional PVI. For induced typical flutter, cavotricuspid isthmus (CTI) ablation was performed in addition to PVI. If no SVT was inducible, PVI was performed with either second-generation 28-mm cryoballoon (CB-2) using the Arctic Front Advance catheter or radiofrequency (RF) using CARTO, based on operator preference. RF-based circumferential PVI was attempted, and no further substrate based or linear ablation were performed. Technical details of both CB-2 and RF PVI were described elsewhere. ,
Patients who underwent ablation of the slow pathway for atrioventricular nodal reentrant tachycardia (AVNRT) or of an AP were discharged the same day or 1 day after ablation without anticoagulation or antiarrhythmic drug (AAD) therapy. For patients with PVI, anticoagulation was continued for at least 3 months and thereafter based on the individual CHA 2 DS 2 -VASc score. To prevent early recurrences of AF, patients continued antiarrhythmic medications for 3 months. All patients completed outpatient clinic visits at 3, 6, and 12 months and additional symptom-driven visits. Ambulatory electrocardiogram monitoring was performed as indicated by symptoms. Any documented episode of atrial tachyarrhythmia (ATA) lasting >30 seconds was considered as recurrent arrhythmia. PVI ablation was offered to patients who developed AF recurrence after initial SVT ablation. Major complications were defined as transient ischemic attack, stroke, pericardial tamponade, pneumo- or hemothorax, high-degree (>70%) PV stenosis, arteriovenous fistula requiring intervention, or severe bleeding from the access sites or internal bleeding resulting in hemorrhagic shock. Hematoma at access sites, pericardial effusion, and PV stenosis (<70%) were considered minor complications.
Continuous data are summarized as median and/or mean and SD. Categoric data were summarized as frequencies and percentages and were compared using chi-square test. Comparisons between baseline characteristics were performed by independent t test, Mann-Whitney rank-sum, Fisher’s exact, or chi-square tests, where appropriate. Statistical analyses were performed using SPSS statistical software (version 22.0; SPSS Inc., Chicago, Illinois). A 2-tailed p <0.05 was considered statistically significant.
Results
A total of 51 very young patients (mean age 24.0 ± 4.2 years, 78.4% men) with recurrent drug-refractory AF (45 of 51, PAF; 6 of 51 persistent AF) underwent EP study and ablation at 5 EP centers. None of the patients had structural heart disease or a family history of AF. None of the patients had documented regular SVT. Baseline clinical characteristics of the patients are listed in Table 1 . EP study induced SVT in 12 patients (23.5%); typical AVNRT in 6 patients, left lateral concealed AP mediated orthodromic atrioventricular reentrant tachycardia (AVRT) in 3 patients; and left superior PV tachycardia, LA appendage tachycardia, and typical atrial flutter in 1 patient each. Degeneration of induced SVT into AF was observed in 4 patients (33.3%) (3 AVNRT and 1 AVRT case). In patients with induced SVTs, AP ablation, slow pathway ablation, or focal AT ablation without PVI was performed as an index procedure. For the patient with induced typical flutter, CTI ablation was performed and PVI was added. The remaining patients underwent CB-2–based PVI (n = 24, 47%) or RF-based PVI (n =15, 29.4%). All targeted veins were isolated. Comparison of clinical characteristics and follow-up data among patients with and without induced SVTs are listed in Table 2 . There were no major complications related to ablation procedures. Two patients in the CB-2 group experienced groin hematoma that resolved spontaneously. Two patients who had AVNRT and the patient with LA tachycardia experienced AF recurrence and received PVI. During a median follow-up of 17.0 ± 10.1 months, 44 patients (86.2%) were free of ATA recurrence. Comparison of induced SVT group and without SVT group demonstrated a similar ATA recurrence rate after stepwise ablation approach (1 of 12 [8.3%] vs 6 of 39 [15.3%], p = 0.53). Follow-up data of patients are depicted in Figure 1 . A total of 6 patients who underwent PVI (15.4%) experienced ATA recurrence. A total of 5 patients underwent redo procedure: PV reconnection was observed in 4 patients (left superior PV in 4, left inferior PV in 4, right superior PV in 2, and right inferior PV in 1 patient) with consecutive reisolation using RF, and in 2 patients, typical atrial flutter was induced and CTI line was performed.
| Parameters | |
|---|---|
| Age (years) | 24.0 ± 4.2 |
| Men | 40/51 (78.4%) |
| Height (cm) | 176.4 ± 7.0 |
| Weight (kg) | 75.3 ± 15.6 |
| Hypertension | 1/51 (1.9%) |
| Diabetes mellitus | 2/51 (3.9%) |
| Paroxysmal atrial fibrillation | 45/51 (88.2%) |
| Number of AF episodes per patient | 2.3 ± 1.1 |
| LA diameter (cm) | 37.2 ± 5.5 |
| LVEF (%) | 59.5 ± 7.0 |
| CHA 2 DS 2 -VaSc score | 0.1± 0.3 |
| Flecainide | 8/51 (15.6%) |
| Propafenone | 7/51 (13.7%) |
| Sotalol | 2/51 (3.9%) |
| Amiodarone | 6/51 (11.7%) |
| Beta-blocker | 29/51 (56.8%) |
| AF diagnosis to procedure (months) | 9.6 ± 9.9 |
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