Mapping and Ablation procedure
Mapping and ablation were performed under the guidance of a CARTO system
(Biosense Webster, Diamond Bar, CA), Ensite system
(Abbott
medical, St. Paul, MN), or Rhythmia system (Boston Scientific,
Washington, DC). All ablation procedures were performed under deep
sedation using propofol, dexmedetomidine, and pentazocine. The
bispectral index (BIS) was monitored and maintained at 40-60. Vascular
access was obtained from the right and left femoral vein and, if
necessary, from right internal jugular vein. 6Fr duodecapolar, 6Fr
decapolar, and 4Fr quadripolar electrode catheters were placed into the
coronary sinus, His area, and right ventricle respectively. After venous
access was secured, intravenous heparin was used to maintain an
activated clotting time more than 300 sec. Electrophysiological study
was performed to determine the presence of AP. Bolus infusion of
adenosine triphosphate (ATP), extra-stimulus from atrium or ventricle,
para-Hisian pacing were underwent to confirm that the antegrade or
retrograde conduction was via the AP. When the supraventricular
tachycardia (SVT) was induced during control or under an isoproterenol
infusion, a standard EPS study was performed to confirm that the SVT was
via the AP. In the case of left sided AP, the trans septal approach was
performed under the fluoroscopic image and the left side mapping was
performed through the trans septal catheter.
The dual chamber map was created by using Rhythmia system and Orion
catheter. The potential reference of 3D map was obtained from two
different cite in the coronary sinus and the maps were obtained from
Orion catheter. Rhythmia system has a specific algorism called “V
overlap”, which identify the local ventricular potential of mapping
catheter. When the V overlap algorism was enabled, the annotation of 3D
map focus on the single chamber only (Figure 1A). But the detail
connection between atrial and ventricular wasn’t clear of this setting.
Once the V overlap algorism was disabled, the annotation of 3D map can
focus on the different chamber and show a 3D color map of the atrium and
ventricle (Figure 1B), which we call the “atrio-ventricular dual
chamber map”9. Each map was obtained during the
ventricular pacing. If there was no retrograde conduction, ventricular
map of antegrade conduction was obtained during the atrial pacing
(Figure 2). The dual chamber map could be created in the case of type C
cases (Figure 3). The 3D map of control group was created by using CARTO
system or Ensite system with ablation catheter. The potential reference
of 3D map was obtained from a single cite in the coronary sinus and the
maps were obtained from ablation catheter. Ablation was performed for
the earliest activation site while considering the local potential.
Non-irrigation 4mm tip catheter or irrigation 3.5mm tip catheter was
used for ablation in order to the operator’s decision. The success of
ablation was defined as the conduction interruption of APs. After 30
minutes waiting time, the recurrence of APs conduction was confirmed
under the isoproterenol infusion and bonus infusion of ATP. The
background characteristics and procedure details were compared between
the dual chamber mapping group and conventional single chamber mapping
group.