Download Catheter ablation of common atrial flutter using the

LocaLisa: Electrical Localization of Endocardial Electrodes.
Fred H. Wittkampf, Richard Derksen, Erik F. Wever, Arthur A Wilde.
University Hospital, Utrecht, The Netherlands
Citation: Pace Vol 20: Abstr. Suppl. April 1997, Page 1075
Abstract 104
Background:
Estimation of the three dimensional (3D) position of an ablation electrode from
biplane fluoroscopic images is inadequate if a systematic lesion pattern is
required for complex arrhythmogenic substrates. We studied the accuracy of a
new electrode localization technique (LocaLisa). Using an orthogonal lead
system, a small high frequency current is delivered through the thorax, using
slightly different frequencies around 30 KHz for the three orthogonal directions.
The resulting high frequency signal, recorded from an endocardial electrode, is
selectively filtered for the three frequencies to obtain a unique measure of the
position of that electrode within the thorax. This method was applied using 2 to 3
different positions of a decapolar catheter in the right or left ventricle of 12
patients (7RV, 5LV). To determine the accuracy within one ventricle, LocaLisa
data obtained from 2 to 3 catheter (20-30 electrode) positions per ventricle were
analysed using calibrated biplane fluoroscopy as the golden standard. For a
particular cardiac segment, data from the 10 electrodes were compared with the
true inter-electrode distances for each catheter position.
Results:
The high frequency currents did not cause any noise on the unipolar or bipolar
electrograms. The mean spatial error of the calculated electrode positions within
one ventricle was 7mm for both ventricles partly due to inaccuracies of biplane
fluoroscopy. When, however, data obtained from 10 catheter electrodes were
compared with the true inter-electrode distances, the relationship between
known and calculated inter-electrode distances was extremely linear with a mean
correlation coefficient of 0.995 (RV) and 0.998 (LV). This compares to a mean
standard deviation of 1.6 and 1mm respectively in a area of 5-6cm in cross
section.
Conclusion:
The LocaLisa method is sufficiently accurate for non-fluoroscopic mapping and
ablation in a single chamber or segment thereof. It does not affect electrogram
recording, and can be applied to any electrode catheter.
LocaLisa Abstract 2
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