Left atrial (LA) fibrosis plays an important role in the pathogenesis and perpetuation
of atrial fibrillation (AF). It may be identified by bipolar voltage (BiV) mapping,
but quantification of fibrosis which previously relied on visual estimation of scar
has been shown to be inaccurate. Our aim was to use a novel automated voltage histogram
analysis (VHA) tool to quantify LA scar burden accurately in patients with AF.LA voltage
was assessed in 100 consecutive patients undergoing first pulmonary vein isolation
(PVI) for paroxysmal or persistent AF using a circular multielectrode catheter to
create high-density LA BiV maps which were analysed using the VHA tool after the procedure.High-density
electro-anatomic maps took 10 min to create and contained a median of 1049 points.
The VHA algorithm accurately quantified the burden of Diseased LA Tissue (≤ 0.5 mV)
and Dense LA Scar (≤ 0.2 mV) with a median of 17.8% and 3.5% respectively. A quartile
classification was applied based on diseased LA tissue burden. Patients in class IV
with the highest diseased LA burden were older (p < 0.0001), more likely female (p
= 0.0095), had higher CHA2DS2-VASc scores (p = 0.0024) and were more likely to have
persistent rather than paroxysmal AF (p = 0.0179) than those in classes I-III.The
VHA algorithm is able to quantify percentage surface area voltage rapidly and according
to preset ranges for the first time. The algorithm offers the potential for classification
of patients undergoing AF ablation into different classes of diseased LA burden, which
may have diagnostic, therapeutic and prognostic implications.
