Outcome measures
First, we evaluated the success rate of SVCI, comparing the CIED group
with the non-CIED group. Other procedural characteristics such as
procedural time, time needed to achieve SVCI, fluoroscopic time, the
reconnection rate of SVCI in the second session, and the incidence of
phrenic nerve paralysis were also compared between the groups. Second,
lead parameters were compared before and after SVCI in the CIED group.
Lead parameters obtained within 1 year before and after AF ablation were
evaluated. Lead parameters after AF ablation were defined as sensing,
pacing threshold, and pacing impedance at the outpatient clinic after
discharge, to exclude transient abnormality of CIEDs in the acute phase.
In patients who had undergone 2 SVCI sessions, we compared lead
parameters before the first session and after the second session.
Finally, we studied the lead failure rate after SVCI and the details of
the lead failure. Lead failure was defined as a sudden impedance
increase (>50% compared with chronic values) in pacing and
high voltage impedance, lead dislocation, and electrical noise artifact
from rapid, non-physiological make-break potentials recorded on the
sensing channel. Oversensing of non-cardiac potentials, not considered
as lead integrity failure, was not defined as lead failure in this
study.14