Temperature-controlled high-power short-duration RF ablation using a diamond-tip catheter reduces subclinical cerebral embolic lesions compared with conventional RF strategies in persistent AF

Background

High-power short-duration (HPSD) radiofrequency (RF) ablation is increasingly used to improve lesion efficiency during atrial fibrillation (AF) ablation. Novel high-energy catheter technologies, including lattice-tip systems, are gaining clinical adoption. However, tissue overheating during high-power RF delivery may promote thrombus formation and cerebral embolization, contributing to silent diffusion-weighted imaging (DWI) brain lesions.1,2 A temperature-controlled RF catheter incorporating a diamond-based tip provides markedly enhanced thermal conductivity, enabling rapid heat dissipation, reduced irrigation requirements, and real-time temperature-guided modulation of delivered power.

Purpose

To evaluate the incidence and burden of cerebral DWI lesions following temperature-controlled HPSD ablation compared with conventional RF strategies in patients undergoing persistent AF ablation.

Methods

Seventy-two consecutive patients with persistent AF underwent pulmonary vein isolation combined with left atrial substrate modification including posterior wall box isolation and anterior linear lesions using a temperature-controlled diamond-tip catheter. RF energy was delivered at 50 W with a temperature limit of 50°C and irrigation flow of 8 ml/min. Applications lasted 20 seconds and were extended by 10 seconds when impedance reduction ≥10 Ω was not achieved. All patients underwent cerebral MRI the morning following ablation. Outcomes were compared with patients enrolled in the POWER-FAST III trial, randomized to lesion index–guided RF ablation at 40 W or fixed HPSD ablation at 70 W for 9 seconds.

Results

A total of 127 patients were analyzed (40 W n=29; diamond-tip 50 W n=72; 70 W n=26). Patients treated with the diamond-tip catheter were significantly older (65.5±9.6 vs 59.7±10.1 years; p=0.001), while male sex predominated across groups (69–76%). Pulmonary vein isolation and all planned linear lesions were successfully achieved in all patients.

New DWI lesions occurred in 48.3% (40 W), 38.9% (diamond-tip), and 69.2% (70 W) of patients (χ²=7.072; p=0.029, figure 1). Among affected patients, lesion burden showed a non-significant reduction with the diamond-tip catheter (2.04±2.27 vs 3.17±2.64 lesions per patient; p=0.109, figure 2). No strokes occurred in the 40 W or diamond-tip groups, whereas four systemic embolic events were observed in the 70 W group.

Conclusion

Temperature-controlled HPSD RF ablation using a diamond-tip catheter was associated with fewer cerebral embolic lesions despite treatment of an older population undergoing extensive substrate modification. Improved thermal regulation during RF delivery may contribute to enhanced neurological safety during contemporary high-power AF ablation strategies.Figure 1Figure 2