Accuracy of the LocaLisa system in catheter ablation procedures

Estimation of the 3-dimensional (3D) position of ablation electrodes from f luoroscopic images is inadequate in the ablation of complex arrhythmogenic substrates. We developed a new technique for real-time 3D localization of i ntracardiac electrodes. Regular catheter electrodes are used as sensors for a high-frequency transthoracic electrical field, which is applied via stan dard skin electrodes. We investigated localization accuracy by comparing me asured and true interelectrode distances between the tip and the 10th elect rode of a decapolar catheter, and the tip and the 4th electrode of a quadri polar catheter during catheter ablation procedures. Long-term stability was analyzed by localization of the proximal His bundle before and after slow pathway ablation. Accuracy achieved with the 54-mm distance between the two outer electrodes of the decapolar catheters was 101% +/- 15%, 95% +/- 10%, and 97% +/- 8% in the right atrium, right ventricle, and left ventricle, r espectively. During catheter ablation procedures, the measured distance bet ween the tip and 4th electrode of the mapping catheter was 100% +/- 15% in atrial flutter, 100% +/- 12% in slow pathway ablation, and 100% +/- 14% in ablations for left ventricular tachycardia. After 2 hours, localization of the proximal His bundle was reproducible within 1.4 +/- 1.1 mm. The LocaLis a technique allows for reproducible, real-time nonfluoroscopic 3D visualiza tion of standard mapping and ablation catheters and is sufficiently accurat e for the creation of linear radiofrequency lesions. The freedom of cathete r choice makes the LocaLisa system an invaluable tool in catheter mapping a nd ablation procedures.