[Reduction of radiological exposure time during radiofrequency catheter ablation procedures using a novel intracardiac localization system based on the Ohm's law].

Background: Three-dimensional nonfluoroscopic system may be helpful to guide radiofrequency catheter ablation procedures and to reduce the radiological exposure. A new intracardiac navigation and multicatheter visualization system based on Ohm's law (LocaLisa, Medtronic, Minneapolis, MN, USA) has been recently introduced. The aim of our study was to assess the efficacy of the Loca-Lisa system in comparison to fluoroscopy-based approach in reducing the radiological exposure time required for radiofrequency catheter ablation procedures.

Methods: One hundred and thirty-seven consecutive patients underwent LocaLisa-based radiofrequency catheter ablation procedures in our cardiac electrophysiology laboratory during 19 months of LocaLisa utilization (from October 2001 to April 2003): 46 atrial flutter, 44 atrioventricular node reentrant tachycardia, 16 atrioventricular reentry tachycardia due to atrioventricular accessory pathway, 14 atrial fibrillation, 11 ectopic atrial tachycardia, and 6 atrioventricular node modulation. We retrospectively compared the radiological exposure times of this group of patients to those of the last 137 patients undergone fluoroscopy-based radiofrequency catheter ablation procedures for curing the same index arrhythmia by the same procedural protocol.

Results: The mean radiological exposure time was significantly shorter for the LocaLisa-based radiofrequency catheter ablation procedures (16 +/- 12 vs 34 +/- 17 min; reduction of 53%, p < 0.01) and it occurred for all the arrhythmia types. The reduction was of 64% (from 39 +/- 18 to 14 +/- 12 min, p < 0.01) for atrial flutter, 42% (from 24 +/- 10 to 14 +/- 11 min, p < 0.01) for atrioventricular nodal reentrant tachycardia, 30% (from 40 +/- 14 to 28 +/- 14 min, p = 0.02) for atrioventricular reentry tachycardia, 57% (from 49 +/- 12 to 21 +/- 13 min, p < 0.01) for atrial fibrillation (right atrial linear lesions), 50% (from 38 +/- 12 to 19 +/- 8 min, p < 0.01) for ectopic atrial tachycardia and 42% (from 12 +/- 11 to 7 +/- 5 min, p = NS) for atrioventricular node modulation. The reduction in the radiological exposure time progressively increased as our team got used with the nonfluoroscopic navigation system.

Conclusions: Overall and single arrhythmia-divided mean radiological exposure times can be significantly reduced by the LocaLisa system during radiofrequency catheter ablation procedures. The reduction of radiation increases progressively by becoming friendly to the system with a very short duration of learning curve phase.