This study represents a real-world case analysis, aligning closely with clinical practice in both study design and follow-up procedures. It lays a robust foundation and accrues valuable insights for the future application of PFA in the treatment of AF. Furthermore, the implementation of propensity score matching in the selection of radiofrequency ablation case controls in this study, significantly mitigated the impact of confounding variables, thereby enhancing the reliability of the results. Through the observation of patients with AF undergoing PFA, initial insights into the efficacy and safety of this treatment modality have been obtained. Our analysis primarily focused on intraoperative parameters including operation time, catheter retention time in the left atrium, radiation volume, number of discharges, pulmonary venous catheter operation time, effective ablation time of the pulmonary veins, immediate success rate of intraoperative PVI, postoperative sinus rhythm maintenance rate, AF recurrence rate, and so on. However, objectively speaking, the rate of postoperative sinus rhythm maintenance and the rate of AF recurrence are crucial clinical endpoints. In comparison to the radiofrequency ablation group, the postoperative sinus rhythm maintenance rate and AF recurrence rate were found to be similar. However, statistically, PFA appears to have a lower recurrence rate, with sinus rhythm maintained in up to 91.7% of cases during the 3- and 6-month postoperative follow-up periods. This rate is slightly higher than the 78.5% observed in the overall paroxysmal AF cohort and the 85% in the optimized biphasic energy PFA waveform cohort, as estimated by the 1-year Kaplan–Meier analysis in the PEFCAT and PEFCAT II studies [
12]. These figures are, however, comparable to the 6% recurrence rate documented in patients diagnosed with AF (
n = 191) in the real-world study conducted by Schmidt et al. [
13] While this study may lack extensive large-scale follow-up data, it is undeniable that patients have reported highly positive feedback regarding their clinical symptoms and surgical experiences during the follow-up period. Furthermore, it is worth noting that most recurrence events in the PFA group were AT, a finding consistent with the results from the study conducted by Tohoku et al. In their research, AT was identified as the predominant type of arrhythmia among the 25 patients who underwent a repeat operation [
14]. Three months after PFA, a patient who experienced recurrent AT underwent successful treatment with radiofrequency ablation. Activation mapping revealed that the AT originated in the superior vena cava. Prior to the mapping, the patient had superior vena cava pulse isolation, but during the mapping, the upper cavity potential was fully restored. Furthermore, in additional matrix mapping, the conduction in both left and right pulmonary veins was substantially restored. Hence, there are lingering concerns about the long-term durability of pulsed pulmonary venous and superior cavity isolation. The results from the 1-year follow-up of the PEFCAT and PEFCAT II studies disclosed notable differences in the quantitative time analysis of pulmonary venous isolation [
15]. In terms of safety, neither group of patients encountered acute thromboembolic events (such as ischemic stroke, transient cerebral ischemic attack, peripheral artery embolism, and so on). In some patients who underwent PFA, the presence of microbubbles was monitored using intraoperative intraluminal ultrasound. Additionally, no instances of pericardial effusion and cardiac tamponade necessitating drainage and surgery, vascular puncture complications, or coronary and pulmonary vascular injuries were reported. These findings underscore a high level of safety associated with the procedure. The results are in line with those reported in current clinical studies [
12,
13,
16,
17]. However, there were two patients who experienced transient intersection escape rhythm with third-degree atrioventricular block (atrial pacing cannot be transmitted downwards) during the ablation of the posterior wall of the left pulmonary vein. Following PFA, ventricular electrodes were subsequently positioned to safeguard ventricular pacing in patients. A post hoc analysis indicated a potential connection between the abundant ganglion in the posterior wall of the left pulmonary vein and vagal reflex, with an incidence rate of 27.3%. Both animal experiments and clinical studies have documented the ablation of the superior vena cava, cavotricuspid isthmus line, mitral isthmus line, and left atrial posterior wall line. These studies have verified the feasibility of additional ablation procedures beyond PVI [
18‐
20]. In the PFA group, successful exploration was achieved in 12 cases (33.3%) of anterior wall line, 14 cases (38.9%) of posterior wall isolation, 6 cases (16.7%) of cavotricuspid isthmus line block, and 16 cases (44.4%) of superior vena cava isolation. Notably, one patient with cavotricuspid isthmus-associated atrial flutter was effectively ablated and terminated through cavotricuspid isthmus line ablation, and another patient with superior vena cava-originating atrial tachycardia was successfully ablated via superior vena cava isolation. In contrast to the local micro-pulsed ablation catheter, the Jinjiang circular catheter utilizes a pulse-released electrode to achieve the objective of local selective ablation. Despite the addition of further ablation to the PVI procedure, no additional complications were reported, including esophageal injury (noted in 33.3% of patients, including those who underwent posterior wall ablation and required postoperative gastroduodenoscopy), phrenic nerve seizures during ablation, phrenic nerve palsy, sinus node injury, or atrioventricular block during the follow-up period. Overall, PFA demonstrated high sinus rhythm maintenance, a low recurrence rate, and high safety in patients with paroxysmal or persistent AF. Apart from animal experiments, the feasibility of additional PVI ablation has been consistently demonstrated in patients undergoing AF ablation, yielding positive outcomes. However, in PFA, akin to radiofrequency ablation, the selection of ablation energy may influence the long-term durability of isolation. Presently, PFA energy selection relies primarily on evidence from animal experiments, lacking substantial patient data on a large scale, necessitating further investigation and research.
Comparing quantitative intraoperative parameters in experimental studies can offer valuable insights into the use of PFA catheters. Variations in operation time among different centers could arise from diverse operating practices. However, most studies have reached a consensus that PFA typically demands a shorter surgical operation time when compared to other ablation methods. However, the results of this study reveal minimal differences in operation time between the PFA and radiofrequency ablation groups. Additionally, there were no statistically significant distinctions in catheter retention time in the left atrium and operation time for the pulmonary venous catheter. This observation could be attributed to the matrix mapping being executed both before and after ablation in the PFA group, a procedure that was seldom performed in the radiofrequency ablation group. An intraluminal ultrasound catheter was used in some patients in the radiofrequency ablation group, allowing for the pre-ablation reconstruction of the left atrial model for three-dimensional anatomical mapping. Although intraluminal ultrasound was used in some patients in the PFA group, it was used in conjunction with the left atrial appendage occlusion after ablation, without the need for model reconstruction. This approach indirectly highlights the remarkable efficiency of the pulsed annular electrode for left atrial modeling and matrix mapping in PFA procedures. PFA also demonstrated a perfect immediate success rate in PVI and required significantly shorter effective ablation time. Leveraging the insights derived from experiences with radiofrequency ablation, it is recognized that a shorter adherent ablation time can mitigate the risks associated with steam bursts and heart rupture. Nonetheless, in the surgical process, the PFA group required more discharges than the radiofrequency ablation group. This phenomenon could be linked to the early recovery of isolation conduction observed in the PFA group. During the post-ablation observation period, it was noted that the potential capacity of the anterior wall of the left pulmonary vein and the top of the right pulmonary vein recovered in most patients. Consequently, repeated ablation was necessary until complete isolation was confirmed. This iterative process led to an increase in both the operation time and the number of discharges. Intraoperative statistics revealed that the operation time of the left pulmonary vein catheter in the PFA group was longer than that of the right pulmonary vein, and it was the same in the radiofrequency ablation group, indicating that the operation time of the pulsed ablation catheter was still limited by the influence of the puncture point and axial direction. It was observed that isolating the left pulmonary vein was more difficult than isolating the right pulmonary vein. Based on a detailed analysis of the PVI process in PFA, it was found that the left superior pulmonary vein required the most time within the left pulmonary vein, whereas the right superior pulmonary vein posed the greatest challenge within the right pulmonary vein. These specific areas are inherently challenging to access during the standard operational procedure. Furthermore, the absence of a tissue adhesion reminder and pressure monitoring in the pulsed ablation catheter can lead to a rise in ineffective adhesion and discharge. This factor may also account for the relatively straightforward recovery of potential conduction in these specific regions. In summary, PFA offers rapid and immediate PVI, thanks to the multi-electrode and annular design of the catheter, which enhances surgical efficiency. However, there is potential for improvement in intraoperative adhesion feedback, pressure monitoring, ablation AI value monitoring, and other aspects. These enhancements are crucial to minimize interference and axial impact on the atrial septal puncture position, as well as to mitigate ineffective discharges and excessive tissue damage. The transition from a radiofrequency ablation catheter to a pulsed catheter was seamless and swift, with surgeons quickly adapting to its usage and mastering the operational skills. This process required no more time than that for radiofrequency ablation, underscoring the shorter learning curve associated with PFA. This observation aligns with the comparisons drawn from similar experiments, confirming the efficiency of PFA in terms of learning and adaptation [
13,
21,
22].
This study is subject to several limitations. The sample size was limited, and individual differences among cases may have introduced a lack of representativeness. Despite employing propensity score matching in the selection of patients for the control group, which substantially minimized potential biases between the two groups, there remain disparities compared to randomized controlled studies.