Outcomes and safety of new techniques for pulmonary vein isolation in patients with paroxysmal and persistent atrial fibrillation : A study based on randomised trials and registries

Abstract: Atrial fibrillation (AF) is a common disease with a high prevalence in the adult population. Treatment of AF encompasses antiarrhythmic drugs and catheter ablation to reduce symptoms. The aim of this thesis was to study how to best alleviate symptoms of AF in a safe and efficient way comparing pharmacological treatment and the two dominating catheter ablation techniques, cryoballoon (CRYO) ablation and point-by-point radiofrequency (RF) ablation.Quality of life improved more for those AF patients randomised to treatment with catheter ablation compared to those treated with antiarrhythmic medication after 12 months of follow up (n=155).We evaluated a proposed optimised CRYO ablation protocol and randomised 140 patients to a single cryoballoon application per vein guided by a mapping catheter (Single cryo) or two cryoballoon applications (Routine). Acute pulmonary vein isolation rate did not differ. Procedure time decreased by 19 minutes with a lower complication rate in the Single cryo-arm. Freedom from AF after one procedure at 12 months did not differ; 73.9.0% (Single cryo) versus 71.4% (Routine).CRYO ablation was also assessed in persistent AF and paroxysmal AF. Freedom from arrhythmia recurrence was lower after a single ablation in persistent AF (64.9%) compared with paroxysmal AF (82.2%) after 12 months. However, the reduction of AF symptoms and quality of life was excellent in both groups and did not differ after 12 months.Patients undergoing their first AF ablation with CRYO or RF were included in a registry study. After 12 months, freedom from AF was equal irrespective of AF type, but there was a lower re-ablation rate and need for continued antiarrhythmic drug treatment after CRYO ablation. Procedure duration was reduced by 40 minutes with CRYO and complication rates did not differ,In conclusion, catheter ablation reduces AF symptoms more than antiarrhythmic drugs and cryoballoon ablation can be further optimised with reduced procedure times and improved safety. Cryoballoon ablation is as efficacious as RF ablation as a first-line therapy in both paroxysmal and persistent AF and the lower re-ablation rates and  shorter procedure times may have important clinical implications when choosing AF ablation technique.