Observational studies
Several observational studies have reported favorable outcomes when
combining PVI with targeted ablation of LVAs; a summary is provided in
Table 1. Rolf et al., performed voltage-guided ablation (VGA) in 178
patients with either paroxysmal or persistent AF (18). Left atrial (LA)
voltage mapping was performed in sinus rhythm (SR) using a multipolar
catheter, with LVAs defined as areas with peak-to-peak voltage
<0.5mV. Twelve-month freedom from AF was comparable between
patients with no LVAs and those with LVAs who underwent PVI plus
ablation of LVAs, and significantly higher in patients with LVAs who did
not undergo such substrate modification. Ziv and colleagues performed
LVA assessment on the posterior wall of the LA through point-by-point
(PBP) mapping in patients with PsAF (19). Patients undergoing VGA of the
posterior wall fared better than those with standard therapy, and this
superiority was maintained over long-term follow-up of 5 years (20).
This could highlight the role of the posterior wall as a trigger for AF,
given the shared embryology with the pulmonary veins.
In keeping with these studies, Jadidi et al. also employed a
peak-to-peak voltage threshold of 0.5mV, however voltage mapping was
performed using a multipolar catheter with subjects in AF rather than SR
(21). Only those’ LVAs, or regions bordering these, harboring distinct
electrogram characteristics suggestive of arrhythmogenesis, such as
fractionation spanning 70% of the AF cycle length, were targeted for
ablation. They observed high rates of AF termination during LVA
ablation, and combining PVI with selective VGA improved freedom from AF
in PsAF compared to a standalone PVI strategy. Arruda and colleagues
also evaluated LA voltage in AF utilizing a threshold of 0.5mV to
delineate LVAs, however voltage mapping was performed manually in a PBP
fashion (22). Single procedure success rates at 12 months were
comparable in patients with LVAs who underwent PVI + VGA ablation and
those without LVAs treated with PVI alone, adding credence to a
prognostic role of LVAs and potential therapeutic benefit in targeting
these with ablation.
Yang et al. employed VGA ablation in 86 consecutive patients with a
history of non-paroxysmal AF (23). LVAs were defined as areas with
peak-to-peak voltage between 0.1 – 0.4mV while transitional zones had a
bipolar voltage range 0.4 – 1.3mV. Within LVAs, ablation was performed
to eliminate all identified electrograms, aiming to achieve an absolute
bipolar voltage of <0.1mV. Further ablation was performed in
transitional zones, targeting abnormal electrograms. When compared with
a historical cohort that underwent stepwise ablation, maintenance of SR
and rates of post-ablation atrial tachycardia were significantly
improved in the study population.