VOM ethanol infusion
VOM ethanol infusion was performed prior to transseptal puncture and
systemic heparinization in the first several cases but following left
atrial mapping in the subsequent ones. From a femoral approach, the CS
was cannulated with an SL-2 sheath over a deflectable decapolar
catheter. A floppy tip straight 0.35” guidewire (MagicTorque, Boston
Scientific or Wholey wire, Medtronic) was advanced passed Vieussens
valve into the great cardiac vein to retain access and a venogram was
performed through the sheath in the right anterior oblique projection to
highlight the VOM. Often the VOM was not identifiable on venography but
was subsequently found either proximal to the sheath tip or just
proximal to Vieussens valve. An IMA guide catheter was carefully
advanced over another 0.35” guidewire into the CS. The guidewire was
then exchanged for an 0.14” angioplasty wire preloaded with an over the
wire balloon to occlude the proximal VOM (1.5mm-2.5mm range though
typically 2mm, Emerge Dilation catheter, Boston Scientific). An 0.14”
PT Graphix wire (Straight tip, 300cm, Boston Scientific) was used for
the initial cases but all subsequent ones were performed with the low
tip weight Suoh wire (0.3 gf, Asahi) to virtually eliminate the risk of
wire perforation. After VOM ethanol infusion, CS ablation was
systematically performed through the SL-2 sheath. A rare subset of cases
were performed from a superior approach, including the initial case in
the series as well as subsequent ones wherein the VOM could not be
stably cannulated from a femoral approach. After proximal VOM occlusion,
a selective venogram was performed and up to 4 injections of anhydrous
ethanol were performed of 1-3 cc, each over 30-60 seconds. Echogenicity
was usually noted on ICE and a low voltage zone of varying size and
confluency was demonstrated on electroanatomical mapping. VOM venograms
were not systemically performed between ethanol injections, fearing
additive risk of dissection of the VOM from viscous iodinated contrast
unless there was suspicion of poor occlusion, balloon movement, or
dissection, particularly in the absence of a significant ethanol
response. Due to a series of dissections noted on initial venography and
the delayed pericardial effusions noted in this study, for the final
twenty one cases in the series, systematic use of the initial VOM
venogram was abandoned unless prompted by concern of poor ethanol
delivery on imaging or mapping due to the perceived dissection risks
from brisk injections of contrast.