We report our initial experience with the newly released ultra-high density (UHD) electroanatomical mapping system (Rhythmia, Boston Scientific) for arrhythmias.

All procedures using the multielectrodes catheter (Orion, Boston Scientific) in our institution, for arrhythmias mapping were analyzed. Procedure and fluoroscopy times were also assessed.

20 patients were included (67,9±13 y) for radiofrequency ablation of accessory pathway (n=2) / typical flutter (n=5) / atrial fibrillation (AF n=2) / post-AF ablation left atrial tachycardia (AT n=6) / focal AT (n=2)/ left and right ventricular ectopies (n=3). 63 maps (3,15 maps per patient) were acquired within a mean mapping time of 18±10min per map, including a mean number of 10024,3±9371 electrograms per map (Figure): RA maps (flutter=12; sinus rhythm SR=14; coronary sinus CS pacing=4); left atrial maps (during tachycardia=18; SR=3; CS pacing=4); right ventricular maps (n=4); left ventricular maps (during tachycardia=3; pacing=1). Acute success was achieved in 19/20 patients. In one patient, the ablation could not be performed in the absence of clinical ectopies. Total procedure and fluoroscopy times were respectively 232±78min and 15,9±8min. No periprocedural complications were noticed.

UHD electroanatomical endocardial mapping can be safely performed in both atria and ventricles and allows fast and accurate mapping.