Procedures
minimal/no, arrhythmia
ARRHYTHMIA
Randomization was assigned in a 1:1:1 ratio, stratified by site in block sizes of six, to either streamlined AVATAR-protocol ablation, optimized anti-arrhythmic therapy, or conventional AF cryo-balloon ablation.Interventions were applied at fixed time points during a 12-week period with the aim of discharging the patient from specialist hospital-based treatment.In the AVATAR-protocol ablation group, the Arctic Front Advance™ cryoballoon (Medtronic, Minneapolis, MN, USA) was used to occlude PVs to achieve minimal/no dye leak on injection. No intra-cardiac electrical recording catheters were deployed, and PVI was not formally assessed. A bedside transthoracic echocardiogram, haemoglobin check, and femoral puncture site assessment were carried out 6 h post-procedure. If all parameters were stable, the patient was discharged on the day of intervention. This was included in the randomized part of the protocol as it has not been tested previously in a controlled clinical trial. Therefore, we did not define it as standard practice even though it is becoming more common.In the conventional AF ablation group, cryo-ablation efficacy was monitored with a circular mapping catheter of the operator’s choice. PVI was completed with either repeat cryo-balloon application, deflectable cryotherapy catheter, or radiofrequency catheter as per operator preference. Post-procedural tests were the same as the AVATAR arm but discharged the next day.During the 12-week treatment period, all pre-ablation anti-arrhythmic agents were continued for 4 weeks post-ablation and then reduced with the aim of stopping. Repeat ablations are required for patients with symptoms due to recurrent AF from PV reconnection. Therefore, a second ablation was permitted at 10 weeks for recurrent AF symptoms as a part of the initial ablative treatment strategy.In the drug therapy arm, patients were reviewed every 4 weeks to optimize anti-arrhythmics. Drug choice and dose recommendation were in accordance with local and international guidelines. At each review, the medication could be left unchanged, the dose altered, or changed to a different agent as required. Drug dosing was optimized to achieve symptom control without side effects. In patients with frequent symptoms, this timescale was expected to be sufficient to maximize drug dosages and in those who had infrequent symptoms to achieve lower maintenance doses with a ‘pill-in-the-pocket’ plan for breakthrough episodes.Patients who were symptomatically improving at the 12-week review were discharged from hospital-based specialist arrhythmia care. Patients who had ongoing symptoms or problems related to their assigned therapy were deemed to have ‘failed 12-week discharge’ and counted as a primary endpoint. Telephone interviews every 3 months ensured appropriate primary care engagement. Hospital-based attendance, investigations, and treatments were adjudicated by a blinded Endpoints Committee.