The place of ablation in the treatment of atrial fibrillation: where are we and where are we going?

Atrial fibrillation, the most common arrhythmia, is frequently disabling and drug resistant and is associated with significant complications, especially thromboembolic events. Non-pharmacological approaches including surgery and catheter-based ablation have been developed for the most symptomatic patients. These new treatment strategies have dramatically increased our knowledge of the pathophysiology of this arrhythmia but most importantly have demonstrated that atrial fibrillation is curable. Since 1994, 2 different concepts have been used, aiming to modify the substrate responsible for AF maintenance using linear lesions, or to ablate the triggers located from within the pulmonary veins (PV) in about 90% of cases. The vast majority of the laboratories in the world are now using approaches centred on isolation of the PV. These approaches are far from being perfect but good enough to be offered in routine practice to selected patients in experienced centres. The importance of PVs in the initiation of AF has been clearly demonstrated and they also have a possible role in the maintenance of AF. However, the existence of non venous foci or a prominent substrate for AF maintenance limits the success rate to about 70%. As a consequence, a combination of PV isolation and linear lesions is commonly used. This more complex procedure carries a significantly higher success rate however with an increased risk of tamponade. As a consequence, we need to identify which patients will require linear lesions in addition to PV isolation. At the present time, AF ablation is restricted to symptomatic patients who have failed at least 1-2 antiarrhythmic drugs but future technical improvements based on presently applied concepts are likely to widen the indications for ablation therapy of AF.     

What have we learned of ablation procedures for atrial fibrillation?

Atrial fibrillation is a widespread disease of growing clinical, economic and social importance. Interventional therapy for atrial fibrillation offers encouraging results, with pulmonary vein isolation (PVI) as the established cornerstone. Yet, the challenge to create durable transmural lesions remains, leading to recurrence of atrial fibrillation in long‐term follow‐up even after multiple ablation procedures in 20% of patients with paroxysmal atrial fibrillation and approximately 50% with persistent atrial fibrillation. To overcome these limitations, innovative tools such as the cryoballoon and contact force catheters have been introduced and have demonstrated their potential for safe and effective PVI. Furthermore, advanced pharmacological and pacing manoeuvres enhance evaluation of conduction block in PVI.     

Antiarrhythmic therapy of atrial fibrillation: are we treating too late?

Atrial fibrillation (AF) is associated with increased risk for stroke, heart failure and mortality. The causality between worse prognosis and AF is not clear at this time and AF may just be expression of underlying heart disease that by itself is associated with increased morbidity and mortality. AF is characterized by progression from rare paroxysmal episodes to permanent AF. It has been well recognized that maintenance of sinus rhythm with either antiarrhythmic drugs or catheter ablation is easier to achieve if treatment is established early on. In addition to the established indication of symptomatic improvement, the focus of AF management is shifting to earlier intervention to prevent cardiovascular complications. This concept is currently under investigation in the ongoing EAST trial. Early treatment initiation is desirable from a pathophysiologic perspective. This includes consequent prevention and treatment of AF risk factors, efforts for early diagnosis, and stroke prevention according to the CHA2DS2-VASc score. As long as no data support prognostic advantages with “aggressive” rhythm control therapy it remains reserved for symptomatic patients, since both, medication and catheter ablation, convey a significant risk for complications.     

Omega 3 and atrial fibrillation: Where are we?

Anti-arrhythmic properties of n-3 polyunsaturated fatty acids, at least in part mediated by anti-oxidant, anti-inflammatory and anti-fibrotic power, have been widely proved. Effect of fish oil on atrial fibrillation, both in primary and in secondary prevention and after cardiac surgery, are controversial, mostly due to lack of homogeneity between studies but also due to individual variability in response to fatty acids administration. Inclusion of measurement of incorporation of fish oil into cell membranes, appears to be essential in future studies, to assess their antiarrhythmic effect.     

Antiarrhythmic drugs in patients with recurrent atrial fibrillation: where are we?

In patients with recurrent atrial fibrillation (AF), the hallmark of treatment has long been the use of antiarrhythmic drugs. The following strategies are available: a) any antiarrhythmic treatment; b) out-of-hospital episodic treatment ("pill-in-the-pocket" approach); c) prophylactic antiarrhythmic therapy; and d) hybrid therapy. The following patients with recurrent AF should not undergo any antiarrhythmic therapy: after the first AF episode; patients with rare, hemodynamically well-tolerated and short-lasting (a few hours) AF episodes; patients with perioperative AF, without history of recurrent AF; patients with AF during acute myocardial infarction or other acute diseases, without history of recurrent AF; and "holiday heart" syndrome. In patients with infrequent AF episodes (< 1 per month) and hemodynamically well-tolerated, but long enough to require emergency room intervention or hospitalization, a good treatment might be the "pill-in-the-pocket" approach, consisting of a single-dose oral ingestion of flecainide or propafenone at the time and place of palpitation onset. A recent Italian study has shown that this treatment is effective and safe. When AF episodes are frequent and/or hemodynamically badly tolerated, the treatment of choice is the prophylactic therapy with antiarrhythmic drugs. When these drugs fail (ineffective or not tolerated) a non-pharmacological treatment or a hybrid therapy may be indicated.