Should most atrial fibrillation patients be treated with catheter ablation?  

Yes ('most' patients), says Stephan Willems,
University Heart Center, Hamburg, Germany

This is an interesting suggestion indeed. If “most” patients include those without symptoms and with long-standing persistent atrial fibrillation (AF), then the simple answer is “no” – because, despite great leaps in technological advances, acceptable success rates in chronic AF are not even on the horizon. 
  
But let us address the real world scenario of catheter ablation availability, impact on symptoms and prognosis, as well as the potential alternatives. The management decisions we have to make are often difficult and complex; balancing the risks and benefits of treatment is often like navigating the seas between Scylla and Charybdis of Greek myth.
 
What about those patients who are symptomatic with paroxysmal AF and have access to high-end healthcare systems including catheter ablation? Nobody would have dared to pose the question ten years ago. But the seminal observation of Michel Haissaguerre and co-workers paved the way for AF ablation becoming a routine procedure in experienced hands. Today, we have to ask what would we do - or recommend - for our relatives and friends affected by symptomatic paroxysmal AF? The answer is that for most patients with symptomatic paroxysmal AF anti-arrhythmic pharmacological options are a distant second choice, and in fact are a potentially deleterious alternative to catheter ablation. 
 
The lack of survival gain from anti-arrhythmic drug treatment with our currently available compounds has been demonstrated in AF patients with (AF CHF trial) and without heart failure (AFFIRM trial). Furthermore, the potentially lethal effect of anti-arrhythmic drugs and the benefit of maintained sinus rhythm in general have been elegantly demonstrated in the oft-cited post hoc analysis of the AFFIRM investigators in 2004, underscoring the concept that “sinus rhythm is indeed better than AF”. But this cannot be achieved using the available agents because of their inefficacy and well recognised side effects such as proarrhythmia. 
 
A recent meta-analysis concluded that amiodarone is the most effective drug. However, it was also pointed out that this is the agent with the highest rate of side effects, and with a tendency to increase mortality with long-term use (similar to sotalol). The good news is that dronedarone has a low rate of side effects and significantly reduces stroke risk and hospitalisation (ATHENA). But despite this, dronedarone cannot be the drug of choice in many patients with symptomatic paroxysmal AF because of its limited efficacy, especially when compared to amiodarone (DIONYSOS trial). 
 
So, taking these difficult treatment decisions into account, we are still left with a choice between Scylla and Charybdis. Catheter ablation, however, especially in the setting of paroxysmal AF, has been shown superior to anti-arrhythmic drug treatment with respect to freedom of arrhythmias during follow-up (77% vs 29% after 12 months).1 This effect is even more pronounced in studies which only included patients with paroxysmal AF. More than half the patients allocated to anti-arrhythmic drug treatment crossed over to catheter ablation during the study. Furthermore, catheter ablation also decreased hospitalisation for cardiovascular causes. Although repeat catheter ablation procedures are often required, long-term success rates of up to 80% are very realistic, thus potentially preventing the progression of paroxysmal to persistent AF.
 
Of course, the rate of major complications has to be taken into account, and this in experienced hands is around 2%. Although uninformed patients may not request catheter ablation (though ever more do!), recent data on single centre experiences and analysis of large registries suggest a positive impact on long-term neurologic event-free survival. This observation is supported by data showing that catheter ablation reduces left atrial size and volume without adversely affecting left atrial function after successful treatment.
 
The 2010 ESC guidelines on the management of AF navigate us through the hazards of treatment decisions by offering the option of catheter ablation in symptomatic paroxysmal patients. Of course, this cannot be the option for “most patients with atrial fibrillation”, but reserved for the subset of patients with symptoms and paroxysmal AF but without well defined aetiology. Although many questions still have to be answered in ongoing studies (CABANA, AMICA, CASTLE-AF, EAST and others), today we can clearly consider catheter ablation as first-line treatment for many patients. Thus, with ever declining complications and increasing success rates, catheter ablation may allow us to steer clear of Charybdis – the hazardous whirlpool of anti-arrhythmic drug treatment - and on to sinus rhythm, while avoiding the rocks of Scylla.