A new interpretation of non-pulmonary vein substrates of the left atrium
in patients with atrial fibrillation.
Background. Substrate analysis of the left atrium in patients undergoing
atrial fibrillation ablation has limitations when performed by means of
simple bipolar acquisition. Objective. To evaluate the incidence of
low-voltages (LV) through maps constructed by means of various
catheters:multipoltar (MC), omnipolar (OC) and circular catheters (CMC)
with the 3D electro-anatomical systems (3d-S) CARTO3 and
Ensite-Precision. Methods. To assess LV we acquired maps by means of CMC
and MC in the voltage range 0.05-0.5 mV in 70 patients in sinus rhythm.
In case of OC only, we made an intra-patient comparison of bipolar maps
constructed in along, across and HD-Wave configurations by means of
Ensite-Precision in the ranges of 0.05-0.5 mV and 0.5-1.0 mV. Basing on
this comparison, we chose the range that best identified LV and
characterized patchy fibrosis by analyzing a set of different colors
(qualitative analysis). Finally, we performed a quantitative analysis of
LV by applying the qualitative characteristics described above. Results.
Basing on our settings, the optimal range for OC was 0.3-0.6 mV. OC
revealed smaller LV areas than MC (p <0.05 or p
<0.001), except in the lateral wall. No significant
differences were observed between CMCs. The same rates of AF recurrence
were found for OC and MC during the follow-up period. Conclusions.In our
experience, OC does not present the limits of bipolar HD maps, though
further studies are needed in order to confirm that 0.3-0.6 mV as LV
optimal voltage range.