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.