Atrial fibrillation, the most prevalent human cardiac arrhythmia, causes unnoticeable to severe symptoms like angina, lethargy, vertigo and dyspnoea. Problematic re-entry circuits perpetually prevent full atrial repolarisation post-atrial systole; preventing optimal atrial filling and ejection, causing ectopic ventricular tachycardia and increasing thromboembolic risk. Paroxysmal atrial fibrillation episodes are isolated or reoccurring and last less than twenty-four hours but gradually increase in frequency and duration until chronic. Effective management slows atrial fibrillation progression. Radiofrequency and cryoballoon ablations are two gold standard interventions for atrial fibrillation where lifestyle and pharmacological intervention fail. Radiofrequency and cryoballoon sever re-entry circuits using heat damage and liquid nitrogen-induced intracellular freezing – respectively. New randomised controlled trials investigating the safety and efficacy of the latest radiofrequency and cryoballoon iterations warrant updated systematic review and meta-analysis. This study aims to elucidate if either radiofrequency or cryoballoon ablation were significantly superior in clinical efficacy or safety.

PubMed and Web of Science databases were searched for relevant randomised controlled trials. Articles with title and abstract terms ‘radiofrequency,’ ‘cryoballoon,’ ‘ablation,’ ‘safety,’ ‘efficacy’ or ‘paroxysmal atrial fibrillation’ were identified via ‘AND’ and ‘OR’ Boolean functions. Articles with title and abstract terms ‘protocol,’ ‘reablation,’ ‘repeat,’ ‘supplementary,’ ‘open ablation,’ ‘combined,’ ‘economic,’ ‘financial,’ ‘comorbidities,’ ‘animal,’ ‘systematic review,’ ‘meta-analysis,’ ‘child’ or ‘adolescent’ were excluded using the ‘NOT’ Boolean function. RevMan 5.4 was used for bias assessment, meta-analysis and forest plot representation of included study data.

Eight recent (2011-2021) randomised controlled trials (three single and five multi-centre) with 1950 human patients (1265 male and 685 female; 949 radiofrequency and 1001 cryoballoon) were identified for systematic review and meta-analysis. There was no significant difference in clinical efficacy outcomes for either radiofrequency or cryoballoon ablation: atrial fibrillation reoccurrence (odds ratio [OR] = 1.13, 95% confidence intervals [CI₉₅] = 0.90-1.41, statistical heterogeneity [I²] = 0%) and reablation (OR = 0.77, CI₉₅ = 0.35-1.11, I² = 0%) rates at 12-months post-ablation or total complication rate (OR = 1.21, CI₉₅ = 0.76-1.92, I² = 0%). Radiofrequency and cryoballoon ablation had significantly lower phrenic nerve injury rate (OR = 0.14, CI₉₅ = 0.03-0.62, I² = 0%) and shorter total procedure duration (standard mean difference = 0.33, CI₉₅ = 0.19-0.46, I² = 0%), respectively.

This report reliably indicates that clinicians and adult patients should not differentiate between radiofrequency and cryoballoon ablation based on clinical efficacy and total complication rate but can reliably discriminate based on phrenic nerve injury rate and total procedure duration. Future high-quality, multicentre, randomised controlled trials with more subgroup classifications (like age, race, gender, paroxysmal versus non-paroxysmal atrial fibrillation) will produce data that applies to more specific patient groups. More rigorous and transparent reporting of study design and bias risk reduction is required to improve future study validity.