Introduction: Atrial fibrillation (AF) is the most common cardiac arrhythmia and the prevalence is increasing every year, especially for persistent atrial fibrillation. The evidence base for rhythm control strategies in persistent atrial fibrillation remains contentious. Cryoballoon ablation is one of the conventional rhythm-control therapies in treatment-resistant AF, and has emerged as a successful therapeutic option as it confers a beneficial effect on procedure time with low rates of reconnection in contrast to most radiofrequency pulmonary vein isolation series. However, there is little UK data to support its use as a first ablation strategy for persistent AF.
Aim: To assess the medium-term efficacy of cryoballoon ablation for persistent AF (1- and 2-year follow-up).
Method: Data extracted from persistent AF cryoballoon ablation database at University Hospitals Plymouth NHS Trust between January 2015 to December 2021 (all cases performed by Dr Guy Haywood). Demographic, echocardiographic and procedural data were collected, as were safety and freedom of AF recurrence at 1 year and 2 years. AF recurrence >30 seconds occurring beyond the 3-month blanking period was assessed by all clinical means available, including a patient reporting telephone line to arrhythmia care co-ordinators. Any ECG evidence of recurrence or documented high heart rate on pulse oximeter or phone app associated with typical symptoms was considered to be a treatment failure. Personal ECG recording devices, 24-hour tapes and pacemaker telemetry all contributed to clinical surveillance.
Results: Ninety-two sequential cases of cryoballoon ablation for persistent AF were included in the analysis, with a median age of 56 (range 30–82), BMI of 34 kg/m2 (range 27–40) (moderately obese), LVEF of 50% (range 30–65) and median LA size ‘moderate dilatation’. Analysis was done at 1- and 2-year time points. All 92 cases (100%) were acutely successful with 4 pulmonary vein isolation. Three patients had post procedure complications: 1 case of small pericardial effusion without drainage, 2 cases of right phrenic nerve injury, one with full recovery, one asymptomatic but persisting. Sixty-nine out of 92 (75%) of patients were free of AF recurrence at 1 year and 57/77 (74%) of patients were free of AF recurrence at 2 years. Of the 77 patients who completed 2 years, 4 patients who were free of AF recurrence at 1 year progressed to AF in the second year, which is 5%. Five out of 20 patients needed re-do procedures during year 2 (all counted as treatment failures). Of the 5 re-do cases, 4 were done at UHP and all 4 pulmonary veins were still isolated at re-do mapping. Overall efficacy of cryoablation in persistent AF at 2 years is probably best considered as 70%, given the second year drop off observed.
Conclusion: Cryoballoon pulmonary vein isolation for persistent AF remains a safe first-time ablation procedure with good clinical outcomes (freedom from AF recurrence 75% at one year and 70% at 2 years) in a typical UK population. ❑
