Cerebral microembolization during atrial fibrillation ablation: comparison of different single-shot ablation techniques

Abstract

Background: Clinically silent cerebral ischemia (SCI) detected by diffusion-weighted MRI has been reported in 5-40% of patients undergoing pulmonary vein isolation (PVI). Although initial reports suggested a high rate of SCI with phased radiofrequency (RF) ablation on use of the pulmonary vein ablation catheter (PVAC), the incidence was subsequently markedly reduced in consequence of procedural modifications in recent studies. We analyzed cerebral microembolization as assessed with transcranial Doppler during phased RF ablation and with two other single-shot AF ablation technologies: the cryoballoon (CB) and the nMARQ™ multipolar irrigated RF ablation system.

Methods and results: A total of 89 patients (mean age: 57, SD: 12years; 62 males) with paroxysmal or persistent AF underwent PVI. Phased RF was used according to the initial protocol in 7 patients (PVAC Group I), with procedural modifications and a newer (14.4) version of the RF generator in 37 patients (PVAC Group II) and with the most recent (version 15.1) generator in 18 patients (PVAC Group III). Ablation was performed with the CB in 13 and with the nMARQ system in 14 patients. The number of microemboli (mean+(SD)) detected in the middle cerebral arteries was 2703 (918) in PVAC Group I, 1087 (542) in PVAC Group II, 719 (469) in PVAC Group III, 1057 (784) with CB and 2166 (1047) with nMARQ (p<0.01).

Conclusion: Significant decreases in MES counts were observed thanks to the procedural modifications and newer RF generator with phased RF. High MES counts comparable to those with the initial phased RF resulted from the use of nMARQ.

Keywords: Atrial fibrillation; Cerebral microemboli; Pulmonary vein isolation; Transcranial Doppler.