Discussion
We compared the procedural characteristics and short-term clinical outcomes of RF ablation of AF in young adults and older adults in this study. Our series demonstrated Patients with young AF have a better chance of being AF-free without the use of antiarrhythmic medications than older patients.
AF is strongly age-dependent, affecting 4% of people over the age of 60 and 8% of people over the age of 80. The prevalence of AF is 0.1% in people under the age of 55[14,15]. A large number of studies focused on catheter ablation and stroke treatment in elderly patients [16,17]. In previous studies, younger patients were under-represented. Julian Chun reported 7243 AF ablation patients in the German Ablation Registry collected from 51 German centers between March 2007 and September 2012 revealed that only 8.2% of patients were under the age of 45[9]. Ghannam demonstrated From January 2000 to January 2019, radiofrequency energy was administered to 82 of 6336 consecutive patients with AF. Because of limited data on procedural characteristics and clinical outcome of catheter ablation in young adults, we are paying closer attention to these patients.
Catheter ablation is recommended as first-line therapy in selected patients with AF and for drug-refractory AF in adults[18,19]. In our study, 77% of the young patients and 67% of the old patients were free of recurrent atrial arrhythmias. There are numerous reasons why younger patients may fare better than older patients. Firstly, the dilation of the atrial structure in AF patients, a feature of atrial remodeling, has been identified as a significant predictor of AF recurrence following catheter ablation. Our data revealed that younger patients had smaller atria, which could be a protective factor. And only the older population (21.7%) had LA scars or Low-voltage areas on voltage maps, indicating LA strutural alterations and fibrosis, compared to the very young population, which all had normal voltage maps[20]. Secondly, in older patients, other poor ablation risk factors such as hypertension, obesity, and obstructive sleep apnea syndrome were higher. However, shorter preablation presence of these risk factors and easier lifestyle modifications after PVI in young patients may explain the differences with old patients[21,22].
Concerning complications, the overall complication rate was low. Clinically significant serious adversee (including death, stroke, TIA) occurred in 120 patients during 6334 procedures. There are several factors that contribute to our study’s lower complication rate. To begin, Spragg[23]et al identified age>70 years as a predictor of major complications. The mean age in our cohort of patients was less than 60 years old, which may have contributed to the lower complication rates. The next, another possible explanation is that 80% of the patients in the population were male atrial fibrillation. There were gender differences in AF patients[24,25]. Cheng[26]conducted a meta-analysis of 151370 patients, 34% of whom were women, and discovered that women who underwent catheter ablation of AF may have a higher risk of stroke/TIA and major complications than men, and that genetic, vascular biology, hormonal, or thromboembolic factors that differ between men and women may lead to a higher risk of complications[27,28]. Furthermore, the included population has a relatively high proportion of patients with paroxysmal atrial fibrillation. Patients with persistent atrial fibrillation require longer surgery time and more complex surgical procedures(such as linear ablation, Marshall ligament) could be be accompanied by higher complication rates [29,30]. Advances in ablation technology, such as irrigation and contact force sensing, as well as better management of AF risk factors may have contributed to this improvement[31], which is also the cause of fewer surgical complications.
Recently, The Early Treatment of Atrial Fibrillation for Stroke Prevention Trial (EAST-AFNET 4) trial looked at the effectiveness of an early rhythm-control strategy in patients who had recently been diagnosed with AF (enrolled median 36 days after AF diagnosis), Early rhythm control reduced the composite primary outcome of cardiovascular death, stroke, and hospitalization for worsening heart failure and acute coronary syndrome by 21% (from 5.0%/year to 3.9%/year) in this trial[32].While AAD therapy has been definitively proven to be superior to placebo in the prevention of arrhythmia recurrence,but the young AF patient must accept a ”lifetime” daily intake of AAD as part of a medical rhythm control plan, as well as the possibility of accumulative side effects, leading to high rates of withdrawn(OR 1.63-2.91)[33]. It’s interesting to note that young patients had a rate of patients who needed particular AAD treatment and anticoagulant drugs even after catheter ablation that was substantially lower, showing that AF control is more likely to be achieved, this finding is consistent with the CHADS2 and CHA2DS2-VASc scores’ predictions of a lower prevalence of comorbidities and thromboembolic events[34].
AF is a chronic progressive disorder[35]. Age and underlying comorbidities are associated with the natural progression rate of PAF to persistent AF, which can reach up to 24.7% over the course of 5 years[36]. After catheter ablation of paroxysmal AF, recent long-term follow-up data showed an unexpectedly low progression rate to permanent AF[37]. Based on this observation, it may be preferable to do an early AF ablation in the young patient rather than waiting until AF has developed into persistent AF, which may then require a lengthy ablation treatment with a lower chance of success[38]. The better outcome was probably caused by younger patients having less electroanatomical remodeling than older patients[39].To better explain the positive response younger patients demonstrated in comparison to the propensity-matched older group, a more extensive assessment of the electroanatomic substrate (such as high-density mapping, evaluation of cardiac fibrosis, and atrial mechanical characteristics) is required.
Study Limitations
The primary limitation of our study is that the data is observational, which makes it susceptible to selection bias. Large registry data, as opposed to controlled randomized trials, may provide additional information to help clarify treatment plan selection and outcome in a ”real world” setting. Second, the decision to use RF or CB ablation was left up to the operators, and the CB method was used differently in different centers. These factors may have influenced the findings, but additional subgroup analysis is not possible given the available data. Third, most studies lacked detailed information on factors such as perioperative drug use, structural heart disease, obesity, and excessive activity, as well as AF in the family. Fourth, most of the follow-up reported in these trials was limited to 12 months. Longer-term follow-up is needed to determine the outcome’s durability in terms of arrhythmia recurrence,healthcare utilization.
Conclusion
According to data from our meta-analysis, young adults who undergo catheter ablation of AF have greater 1-year success rates. In compared to the older group, the young patients tended to have comparable rates of complications (stroke/TIA, hematoma, cardiac tamponade, and pericardial effusion).
Conflict of interest
On behalf of all authors, the corresponding author states that there is no conflict of interest influenced by the article’s content.
Funding
The project was supported by funding from the following: the National Natural Science Foundation of China [82060075];
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Table 1 Baseline characteristics of the included studies