Title : Atrial fibrillation ablation: Where do we stand now?
Atrial fibrillation (AF) is the most common sustained arrhythmia in humans with a rapidly growing prevalence world-wide. Elevated stroke risk, impaired quality of life and increased mortality are related to AF and its significant economyc burden on health care systems have also been demonstrated.
Antiarrhythmic drugs to maintain sinus rhythm offer limited long-term success, while transcatheter ablation has gained increasing popularity as the treatment modality with the highest success rate for rhythm control. Almost 25 years after the first report by Haissaiguerre and collaborators, catheter ablation for AF is still an evolving technology with more open questions and dilemmas than certainties and firm answers related to patient selection, technical aspects and periprocedural anticoagulation.
Clinical data which have accumulated so far suggest that the cornerstone of AF ablation is the electrical isolation of all pulmonary veins (PVs). The value of additional ablative lesions aiming at the abolition of complex fractionated electrograms, creation of linear lesions within the right or left atrium or targeting autonomic ganglions is controversial. Different techniques and ablation energy sources have been in use including radiofrequency current with saline irrigation to cool the catheter tip, cryoballoon to freeze the ostium of the PVs and laser energy. Further, different mapping and navigation systems can facilitate catheter manipulation within the atria.
As far as patient selection is concerned, the highest long-term success rates, usually above 70% can be expected in lone AF or in patients with less comorbidities, normal size left atrium and paroxysmal AF. The procedure improves quality of life in these cases. Recently, 2 large-scale multicentre studies evaluated AF ablation in sicker patients including those with significant comorbidities (CABANA) and with heart failure (CASTLE-AF). Additionally, these were the first trials which used hard endpoints including total and cardiovascular mortality and stroke. The intention to treat analysis of CABANA demonstrated no significant advantage of AF ablation as compared to conventional treatment. CASTLE-AF however showed superiority of AF ablation for heart failure patients in all endpoints.
Audience take away:
- Concept of atrial fibrillation ablation
- Technical aspects of AF ablation
- Short and long-term results of this therapy in different patient population