Cryoballoon Ablation Procedure
The general description of a cryoballoon ablation procedure has been
previously published6, 7 and each center utilized
their own standard-of-care practices during the cryoballoon ablation
procedure. Transesophageal echocardiogram was performed prior to each
procedure.
Venous access was obtained bilaterally with ultrasound guidance. Number
of access sites were determined by the operator but on average, patients
had two catheters on each side. In brief, patients were treated under
general anesthesia or conscious sedation. A transseptal needle puncture
for left atrial access was immediately followed by a heparin bolus
delivery. Activated clotting time was monitored (every 15-20 minutes)
throughout the procedure and was targeted to ≥ 300 seconds. A
purpose-built delivery sheath (FlexCath; Medtronic, Inc, Minneapolis,
MN) was used to advance the cryoballoon (23- or 28-mm Arctic Front
Advance; Medtronic, Inc) and the Achieve mapping catheter (Medtronic,
Inc) into the left atrium. Pulmonary vein occlusion with cryoballoon was
assessed by retrograde contrast agent retention under fluoroscopy
imaging and/or intracardiac echocardiography under Doppler imaging and
pressure wave-form monitoring. 6, 7 The number of
freeze applications and duration of freezes were determined by the
center’s standard-of-care and individual physician preferences; however,
in general, the three centers practiced a freeze dosing methodology that
utilized acute time-to-isolation monitoring to adjust cryoballoon
freezing durations and overall number of freeze
applications.7, 8 Testing for bidirectional block was
utilized at each pulmonary vein to establish acute pulmonary vein
isolation. At the end of the procedure, intracardiac echocardiogram or
transthoracic echocardiogram was performed to exclude pericardial
effusion, a protamine delivery was administered when a reversal of
heparin was desired, and groin sheaths were pulled with compression on
the femoral vein puncture site or insertion of a figure-8 stich.
Figure-8 stich was removed 4 hours after the end of the case and patient
was ambulated prior to discharge. No closure devices were used in any
patient. Antiarrhythmic drugs were utilized within the 90-day blanking
period at the discretion of the treating physician.