Evaluation of a novel high-resolution mapping system for catheter ablation of ventricular arrhythmias

The mapping of ventricular arrhythmias in humans using a minibasket 64-electrode catheter paired with a novel automatic mapping system (Rhythmia) has not been evaluated.

The purpose of this study was to evaluate the safety and efficacy of mapping ventricular arrhythmias and clinical outcomes after ablation using this system.

Electroanatomic maps for ventricular arrhythmias were obtained during 20 consecutive procedures in 19 patients (12 with ventricular tachycardia [VT] and 2 with ventricular ectopy [VE]). High-density maps were acquired using automatic beat acceptance and automatic system annotation of electrograms.

Forty-seven electroanatomic maps (including 3 right ventricular and 9 epicardial maps) were obtained. Left ventricular endocardial mapping by transseptal (n = 13) and/or transaortic (n = 11) access was safe with no complications related to the minibasket catheter. VT substrate maps (n = 14; median 10,184 points) consistently demonstrated late potentials with high resolution. VT activation maps (n = 25; median 6401 points) obtained by automatic annotation included 7 complete maps (covering ≥90% of the tachycardia cycle length) in 5 patients in whom the entire VT circuit was accurately visualized. VE timing maps (n = 8) successfully localized the origin of VEs in all, with all accepted beats consistent with clinical VEs. Over a median follow-up of 10 months, no arrhythmia recurrence was noted in 75% after VT ablation and 86% after VE ablation.

In this first human experience for ventricular arrhythmias using this system, ultra-high-density maps were created rapidly and safely, with a reliable automatic annotation of VT and consistent recording of abnormal electrograms. Medium-term outcomes after ablation were encouraging. Further larger studies are needed to validate these findings.