José Merino, MD

A substudy of the POWER FAST III trial demonstrated that a high-power, short-duration radiofrequency (HPSD RF) application for pulmonary vein isolation (PVI) is associated with a higher risk for subclinical stroke lesions in patients with atrial fibrillation (AF) than conventional RF applications.

The use of “diffusion-weighted MRI (DWI) has revealed that novel, ischemic lesions may arise in patients with AF undergoing catheter ablation, with a particularly high incidence in those who are treated with some of the newer techniques or catheters,” explained José Merino, MD, who presented these findings at the 2023 European Heart Rhythm Association (EHRA) in Barcelona, Spain¹. The researchers aimed to compare the rates of procedural, subclinical complications, and both strokes and bleedings, for patients who were randomized to one of the two RF applications used in the POWER FAST III trial.

In 144 patients, a cerebral DWI study was conducted 24 hours after catheter ablation: 75 received the low-power, long-duration (LPLD) RF modality, and 69 patients were treated with the HPSD RF application. Of note, three patients in the HPSD arm were removed from the analysis due to the occurrence of a TIA or clinical stroke.

In 41.1% of patients, subclinical ischemic brain lesions were observed. However, the rate of ischemic brain lesions was significantly higher in patients who received HPSD RF ablation than in those who were treated with LPLD RF ablation (59.1% vs 25.3%; P<0.001). Moreover, within the subgroup of patients who displayed lesions, the number of lesions was higher in the HPSD arm than in the LPLD arm (P<0.001).

A multivariate logistic regression analysis showed that HPSD (OR 4.9; P<0.001) and persistent AF (OR 3.8; P=0.001) were independent predictors of DWI lesions. Finally, the rate of microbleeds was not significantly higher in the HPSD arm compared with the LPLD arm (27.3% vs 16.0%; P=0.100).

“HPSD RF for PVI was associated with an increased risk for subclinical stroke lesions as compared with LPLD RF ablation,” Dr. Merino concluded.

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