High-power, short-duration ablation linked to a higher stroke risk 

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

“Diffusion-weighted imaging (DWI) has revealed that novel, ischaemic lesions may arise in patients with AF undergoing catheter ablation, with a particularly high incidence in patients who are treated with some of the newer techniques or catheters,” explained Dr José Merino (La Paz University Hospital, Spain). The current substudy aimed to compare the rates of procedural, subclinical complications (both strokes and bleedings) for undergoing HPSD or low-power, long-duration (LPLD) radiofrequency in the POWER FAST III trial (NCT04153747).

A cerebral DWI study was conducted 24 hours after the procedure in 144 patients; 75 received the LPLD radiofrequency modality, and 69 patients were treated with the HPSD radiofrequency application. Of note, 3 patients in the HPSD arm were removed from the current analysis due to the occurrence of a clinical stroke or TIA.

Subclinical ischaemic brain lesions were observed in 41.1% of the patients. However, the rate of ischaemic brain lesions was significantly higher in patients who received HPSD radiofrequency ablation than in patients who were treated with LPLD radiofrequency 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). Furthermore, 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=0.1).

In conclusion, HPSD radiofrequency for PVI was associated with an increased risk for subclinical stroke lesions as compared with LPLD radiofrequency ablation.

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   1. Merino JL, et al. An MRI substudy of the POWERFAST III trial: Substroke. Late-Breaking Science Day 1, EHRA 2023, 16–18 April, Barcelona, Spain.

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Posted on 3 May, 20233 May, 2023