Introduction:
Cryoablation to achieve pulmonary vein isolation (PVI) to treat
paroxysmal atrial fibrillation (PAF) is well
established.1 Cryoballoon treatment has been available
for PVI since the Arctic FrontTm (Medtronic, MN, USA)
was launched over 15 years ago.2 STOP-AF demonstrated
first generation cryoballoon superiority to AADs,3 and
later Fire and ICE demonstrated comparable efficacy of cryoballoon to RF
ablation.4 FIRE and ICE showed comparable efficacy of
radiofrequency and cryoballoon but cryoablation has a distinct safety
profile compared to RF, shifting primary safety events from heat
associated pericarditis/perforation to cold associated phrenic nerve
impairment and PV stenosis.4 Despite over a decade of
use the safety profile of cryoablation remains relatively
unchanged.5-10
Recently a novel 28 mm cryoballoon system that operates under markedly
lower pressure and maintains constant balloon size during cooling became
available for clinical studies.11 Additionally, a
second generation of this novel cryoballoon that allows inflation and
ablation at 2 sizes, 28mm or 31mm, has also become
available.12 At present there is limited long-term
(1yr) outcome data on this novel cryoballoon, and little data available
on the safety or effectiveness of the novel variable size
cryoballon12 While multiple studies have reported both
acute procedural data,13-16 and chronic 1 year
outcomes,17-19 only a few reports of large patient
cohorts exist.13,14,18,20,21
FROZEN AF is an international multi-center, open-label, prospective,
single-arm study to determine the safety and performance of a novel
cryoballoon system for treatment of PAF, and an extension arm which
examined the safety and performance of a novel variable size cryoballon.