LVAs detected using the HDG
An increased amount of fibrosis as detected by LA voltage mapping has
been shown to be a predictor of AF/AT recurrence after AF
ablation.5,6,7 The extent of the LVAs was categorized
on the basis of the LA fibrosis grade evaluated by delayed-enhancement
magnetic resonance imaging (MRI).20,21 However, the
definition of the LVAs and their correlation with histological fibrosis
remains controversial, because the bipolar voltage amplitudes depend on
the electrode orientation relative to the direction of the wavefront,
electrode length, interelectrode spacing, and tissue
contact.22 Furthermore, the HDG when used for bipolar
recording can record not only the parallel but also the perpendicular
activation to the splines, which differs from conventional
mapping.23 Therefore, the HD grid could create high
density maps to define anatomical substrates regardless of the direction
of the activation. In this study, the HDG drastically decreased the
extent of the LVA. The HDG may improve the directional sensitivity and
exclude any false low-voltages, and can detect the AF substrate more
accurately, which would lead to a more effective ablation
strategy.23