Three ablation strategies using very high-power short-duration catheter in paroxysmal atrial fibrillation: The...

Very high-power short-duration (vHPSD; 90 W/4 sec) ablation shortens pulmonary vein isolation (PVI) but produces shallower lesions that may be inadequate in the thick anterior left atrium.

To compare vHPSD, ablation index (AI)-guided, and hybrid strategies for PVI in paroxysmal atrial fibrillation.

In this multicenter, randomized, open-label trial, 150 patients with paroxysmal atrial fibrillation were assigned 1:1:1 with the QDOT MICRO catheter to (1) AI-guided (AI 500 anterior, 400 elsewhere), (2) hybrid (AI-guided anterior [AI 500], vHPSD elsewhere), or (3) vHPSD (90 W/4 sec, all segments). The primary endpoint was total ablation time; secondary endpoints included acute PV reconnection, safety, and 1-year freedom from atrial arrhythmia.

Acute PVI was achieved in all patients. Total ablation time was longest with AI-guided and shortest with vHPSD ablation (median 2220 vs 1450 vs 794 sec; P < .001). Acute reconnection across the 14 PV segments was lowest with AI-guided and highest with vHPSD (7.7% vs 9.4% vs 10.6%; P = .40). One-year freedom from atrial arrhythmia was 92.0%, 85.4%, and 77.6%, respectively (log-rank P = .13; for AI-guided vs vHPSD; P = .049). No tamponade occurred; steam pops occurred only in the 90 W groups. Two minor periprocedural strokes occurred (both vHPSD; full recovery), and silent cerebral lesions on magnetic resonance imaging did not differ among the groups (5%, 10%, 0%; P = .35).

Uniform vHPSD more than halved PVI ablation time but was associated with the lowest 1-year efficacy, whereas the hybrid strategy preserved efficiency without significant loss of durability. These exploratory findings-from a trial powered for ablation time-support region-tailored lesion depth in point-by-point ablation and warrant confirmation.