Abstract Body (Do not enter title and authors here): [Background]
Pulsed-field ablation (PFA) has been introduced as a non-thermal energy source for atrial fibrillation (AF) ablation. However, a safety alert regarding cerebral infarctions with the VARIPULSE system has raised concerns about the risk of stroke. Additionally, microbubble formation during PFA has been reported in animal models, suggesting a possible link to cerebral infarction.
[Objective]
To determine the frequency of microbubble formation during PFA in real-world practice and investigate its association with asymptomatic cerebral infarctions (ACIs).
[Methods]
We analyzed 31 patients with AF who underwent PFA using either the FARAPULSE or PulseSelect system. Microbubble formation was assessed by intracardiac echocardiography in the aortic arch and right brachiocephalic artery during each PFA application. Bubbles were graded on a 0–3 scale (none to severe). A total microbubble score was calculated for each patient as the sum of the products of bubble grade and frequency. Brain MRI was performed ~24 hours after ablation. The association between this score and ACI was evaluated.
[Results]
The mean age was 68.3 ± 10.1 years, and 23 patients were male. Nineteen had paroxysmal AF, and 12 had persistent AF. The mean number of PFA applications was 39.0 ± 6.1 per patient, with no significant difference between the FARAPULSE and PulseSelect groups. Microbubbles were observed in 492 of 1,209 PFA applications, significantly more frequent with PulseSelect than with FARAPULSE (64.2% vs. 22.4%, p < 0.001). Brain MRI was performed in 21 patients (9 FARAPULSE, 12 PulseSelect), detecting 13 ACIs—4 in FARAPULSE and 9 in PulseSelect (not statistically significant). Among patients with persistent AF, ACIs were seen in 6 of 8 cases; in paroxysmal AF, in 7 of 13 cases (p = 0.64). The number of PFA applications was not associated with ACI occurrence (p = 0.916). However, a higher total microbubble score was significantly correlated with ACI presence (p = 0.002). No symptomatic strokes occurred.
[Conclusion]
Microbubbles were frequently observed during PFA, particularly with the PulseSelect system compared to FARAPULSE. However, there was no significant difference in the incidence of ACI between the two systems. A significant correlation was observed between the total microbubble score and the occurrence of ACI.