Whether ultra-high density (UHD) contact mapping is useful in radiofrequency ablation of persistent atrial fibrillation (AF) is unknown.

To sequentially map the left atrial (LA) activation during AF ablation (circumferential PVI and ablation of extra pulmonary vein drivers).

Time reference was an LA appendage (LAA) electrogram (EGM). Points were acquired with respiratory gating if reference, cycle length (10ms tolerance) and electrode location were stable. For fragmented EGM the timing of the surrounding area was used. In case of extremely low voltage (<0.01mV) or lack of local statistical coherence no colour-code was displayed (grey area). Circular propagation around single points was defined as organized rotating drivers (Fig. 1). All pts had PVI followed by remapping and ablation of the centre of rotational regions and at sites with focal type propagation. DC or chemical cardioversion were not performed in the first 48h.

Out of 41 patients (pts) undergoing first time ablation with the above described protocol, 30 (66±8 y, mean current episode duration 8 months) were followed for a mean time of 14,7 months. At 48hours post-procedure, 70% of pts were no longer in AF: 6 (20%) in sinus rhythm and 15 (50%) in atrial tachycardias. At 1 year after a single procedure, freedom from AF was 87% and freedom from AF and AT was 60% (Fig. 1).

In persistent AF, sequential UHD activation mapping is useful in guiding and potentially improving long-term results of ablation of extra pulmonary vein drivers after PVI.