Cyroablation for Pulmonary Vein Isolation Alone in Patients with Early Persistent AF Assessed by Continuous Monitoring

Atrial fibrillation is the most common cardiac arrhythmia. With the population aging, the prevalence of atrial fibrillation is increasing globally. Recently, Cryoablation has been demonstrated non-inferior efficacy and safety compared with catheter ablation in atrial fibrillation patients. Cryoablation with the simplicity of the procedure brought the substantial shortening of the total procedure time compared to catheter ablation with comparable long-term atrial fibrillation free survival and procedure-related adverse events. However, most of the previous studies that reported non-inferior efficacy and safety of Cryoablation versus catheter ablation were only included patients with paroxysmal atrial fibrillation. The long-term efficacy of Cryoablation in patients with persistent atrial fibrillation is controversial.

In patients with persistent atrial fibrillation, pulmonary vein isolation alone showed comparable atrial fibrillation recurrence rate compared to pulmonary vein isolation with additional ablation, including linear ablation or ablation of complex fractionated electrograms.

In a recent study, Cryoablation was safe and had good outcomes in patients with persistent and long-standing persistent atrial fibrillation within relatively short procedure time; atrial fibrillation recurrence rate was 36% in persistent atrial fibrillation and 43% in long-standing persistent atrial fibrillation. Among patients with persistent atrial fibrillation ≤1 year, pulmonary vein isolation using cryoballoon had 39% of any atrial fibrillation/atrial tachycardia recurrence rate during a 1-year follow-up. Pre-predictor such as smaller left atrium size or atrial fibrillation history less than three years was associated with a better outcome of atrial fibrillation cryoablation. Therefore, early ablation of persistent atrial fibrillation using Cryoablation may be related to a good outcome that is nearly comparable to those with paroxysmal atrial fibrillation. Namely, pulmonary vein isolation by Cryoablation could be reasonable as the first procedure in patients with early persistent atrial fibrillation. Based on the results of the STOP Persistent atrial fibrillation trial, the Arctic Front Advance cryoablation system (Medtronic) was granted an expanded indication by the US Food and Drug Administration for the treatment of recurrent, drug-refractory, symptomatic, persistent atrial fibrillation. It is the first ablation catheter in the United States to receive an indication for persistent-as opposed to paroxysmal-atrial fibrillation.

Not only atrial fibrillation recurrence merely defined as any atrial fibrillation episode lasting 30 seconds or more, but the atrial fibrillation burden is also a relevant indicator for evaluation of procedure success. Among patients with paroxysmal atrial fibrillation, a recent prospective study reported that atrial fibrillation burden dramatically decreased after Cryoablation by 99% . There was limited data about the efficacy of Cryoablation in patients with early persistent atrial fibrillation evaluated by actual atrial fibrillation burden using continuous cardiac rhythm monitoring.

Inclusion criteria

• Drug refractory symptomatic persistent atrial fibrillation diagnosed within 3 years
• Either two conditions

• atrial fibrillation episode lasting longer than 7 days, but less than 3 years documented by consecutive electrocardiogram recordings of 100% atrial fibrillation greater than 7 days apart or
• atrial fibrillation episode requiring electrical or pharmacological cardioversion after 24 hours of atrial fibrillation documented by continuous recording
• Willing to comply with study requirements and give informed consent to participate in this clinical study

Exclusion criteria

• Long-standing persistent atrial fibrillation more than 3 years
• Sinus rhythm at enrollment
• Recurrent sinus rhythm after electrical cardioversion
• Severe left ventricular dysfuncion (left ventricle ejection fraction < 30%)
• Previous ablation procedure or surgery for atrial fibrillation
• Contraindication to chronic anticoagulation therapy or heparin
• Documented left atrial diameter >50 mm from parasternal long-axis view
• A percutaneous coronary intervention or myocardial infarction ≤3 months
• A stroke or transient ischemic attack ≤6 months
• Planned cardiovascular intervention
• Mental or physical inability to participate in the study
• Participation in another randomized clinical trial
• Uncontrolled hypertension, untreated hypothyroidism or hyperthyroidism
• Requirement for dialysis due to terminal renal failure