Introduction:
Atrial fibrillation (AF) is the most frequently diagnosed arrhythmia in
practice. AF is also the most heavily associated arrhythmia with poor
outcomes, such as morbidity, mortality and poor quality of life (1,2).
Current guidelines on management of AF suggest that patients should be
treated with antiarrhythmic drugs (AAD) as first-line therapy, but if a
patient becomes refractory to AAD, catheter ablation (CA) with pulmonary
vein isolation is recommended as the next in line treatment (3). The two
methods of CA being used today are radiofrequency (RF) CA and
cryoablation (4).
Contrary to the current recommendations, three popular randomized
control trials (RCT’s) (RAAFT-1, RAAFT-2 and MANTRA-PAF) have shown that
when comparing RF CA to AAD, RF CA had more favorable outcomes in
younger patient populations, when used as first-line therapy; however,
these patients were more likely to develop adverse effects, including
pericardial effusion with tamponade (5,6,7). The more recent CABANA RCT
showed that the risk of death, disabling stroke, serious bleeding or
cardiac arrest were similar in AF patients treated initially with either
AAD or RF CA. However, it did find that AF patients who were initially
treated with RF CA, had more favorable outcomes in total mortality,
cardiovascular hospitalizations and AF recurrence (8).
FIRE AND ICE was the first trial to compare cryoablation to RF CA in the
treatment of refractory AF. The study showed that cryoablation and RF CA
did not significantly vary in terms of efficacy (9). However, patients
who were treated with cryoablation CA had significantly fewer AF
recurrence, and cardiovascular, and all-other-cause re-hospitalizations
as compared to patients who received RF CA (10). Moreover, in light of
new studies directly assessing the efficacy of cryoablation CA as
first-line treatment in comparison to AAD, cryoablation CA had improved
ability to reduce the recurrence of AF in a 12-month period, as well as
have relatively low risk of operation-based complications (11,12).
Finally, the recent study “CRYO-FIRST” once again showed that
Cryoablation CA as first-line therapy displayed significant improvement
when compared to AAD’s in reducing atrial arrhythmia recurrence in
relatively young patients with paroxysmal AF (13).
A recent systematic review studied the previously mentioned RAAFT-1,
RAAFT-2 and MANTA-PAF studies along with three studies that utilized
cryotherapy (CRYO-FIRST, STOP-AF, and EARLY-AF) as the method of
ablation. The results showed significant decrease in recurrence of
atrial arrhythmia and hospitalization (14).
This review aims to assess the effectiveness of cryotherapy CA alone as
first-line therapy when compared to AAD. This study could contribute to
establishing further guidelines on specific first-line treatment for AF.