Protocol of rapid electrical stimuli from the SVC
Rapid electrical stimuli were delivered at a portion of the shortest
SVC-ERP to induce AF. Pacing with a 2-ms duration and three times the
voltage of the threshold was delivered as 40 beats of pacing with an
initial pacing cycle length (PCL) of 500 ms, which was shortened by
50-ms increments down to 250 ms, after which the PCL was shortened by
10-ms increments from 250 ms to 160 ms 13. In the case
of a Wenckebach conduction block or two-to-one SVC-RA conduction block
as the PCL was shortened without AF induction, these groups were
assigned to the non-SVC-induced group (non-SIG). If AF was induced
(Figure 2), these groups were assigned to the SVC-induced group (SIG).
SVC isolation was performed only in patients with reproducible induction
of AF from the SVC using adenosine triphosphate or isoproterenol, and
there was a sufficient margin of at least 1 cm from the sinus node to
the isolation line.