Discussion:
The m-FAM is a novel algorithm that was recently added to the CARTO 3
system. It allows the easy and fast creation of a 3-dimensional
reconstruction of the LA based on very limited FAM mapping. The system
applies machine learning techniques for LA reconstruction using an
adaptive model trained from over 300 LA anatomies obtained from CTA
scans. However, the accuracy of this reconstruction has not been
verified as well as the feasibility and safety of atrial fibrillation
ablation guided by the m-FAM reconstruction.
In the present study, we also evaluated the m-FAM reconstruction to the
CTA of the LA in the same patient. We found that a precise
reconstruction of the LA can be obtained within 4 minutes (including the
algorithm reconstruction time) and with less than 2 minutes of
fluoroscopy-time regardless to the mapping catheter used. In a minority
of patients, adjustments are needed to improve the accuracy of the
reconstruction. The algorithm performed just as well in patients with LA
anatomy different from the classical four PV anatomy (Figure 5). The
fastest m-FAM reconstruction was obtained with the use of a Pentaray for
mapping. This approach might be preferable in patients in which a
substrate mapping of the left atrium is also required, like patients
with long standing persistent AF. Importantly, the voltage map of the
left atrium can be displayed on the shell of the M-FAM reconstruction
when needed (Figure 5). Despite the shortest mapping time required when
using a Pentaray catheter, the accuracy of the m-FAM map was similar in
patients in whom the maps were created solely with the ablation
catheter. The m-FAM reconstruction closely resembled the LA anatomy
obtained from cardiac CTA in all patients. Pulmonary veins angiography
is routinely performed in our lab during AF ablation and therefore it
was included in the two workflows analyzed in our study. Nevertheless we
believe this step is not mandatory for operators who are not comfortable
with it. The ablation guided with the use of the m-FAM reconstruction
was effective with isolation of 100% of the pulmonary veins ablated. No
complications occurred in any of the patients treated who underwent an
m-FAM based ablation.