At Boston AF, Hugh Calkins (director of Cardiac Arrhythmia Service, Johns Hopkins Medical Center, Baltimore, Maryland, USA) gave a sneak preview of the forthcoming 2012 Heart Rhythm Society (HRS), European Heart Rhythm Association (EHRA), and European Cardiac Arrhythmia Society (ECAS) consensus document on catheter ablation for atrial fibrillation.
According to Calkins, the new document is not just a “brief update” of the previous HRS/EHRA/ECAS document, which was published in 2007, but a “comprehensive, state-of-the-art review of the field of catheter and surgical ablation for atrial fibrillation.” He added it currently had 210 pages (although it will be shorter when it is published in March), 736 references, and 11 different sections. He said: “We anticipate that people will read a particular section when they have a particular question.”
“Probably the biggest change” in the new consensus document, Calkins said, was to provide a class of indication and level of evidence for each indication for catheter and surgical ablation. For example, catheter ablation is recommended with a class 1 indication, level of evidence A for patients with symptomatic, paroxysmal atrial fibrillation who are refractory to antiarrhythmic drugs. Calkins said this reflected the nine randomised controlled trials that have shown the superiority of catheter ablation in this setting. But, he explained that this recommendation only applied if the procedure was being performed by an experienced electrophysiologist in an experienced setting. He added: “With persistent atrial fibrillation [in symptomatic patients who are refractory to antiarrhythmic drugs], catheter ablation is reasonable with a 2A indication and level of evidence B. We have less data here.” Catheter ablation can also be considered in patients with long-standing persistent atrial fibrillation who are refractory to antiarrhythmic drugs, but again the lack of prospective randomised controlled trials means that the class of indication and level of evidence is weaker (2B, level of evidence B).
The consensus document also has recommendations on catheter ablation for patients (with paroxysmal, persistent, or long-standing persistent atrial fibrillation) prior to receiving antiarrhythmic drugs, but the class of indication and level of evidence stated varies depending on the available data.
As well as reviewing catheter ablation, the consensus document also reviewed surgical ablation. Calkins explained regardless of whether the patient had paroxysmal, persistent or long-standing persistent atrial fibrillation, in patients who had failed on an antiarrhythmic drug, concomitant surgical ablation had a 2A indication, level of evidence C. In patients who had not failed on an antiarrhythmic, the class of indication for concomitant surgical ablation varied depended on the type of atrial fibrillation but the level of evidence was always C. Calkins said: “What about stand-alone surgical ablation? Basically if you are symptomatic and have failed on an antiarrhythmic drug, it is 2B and level of evidence C all the way down [the different types of atrial fibrillation]. If you are symptomatic and have not failed on an antiarrhythmic drug, then it is class 3 indication and level of evidence C-meaning that if you have not tried a drug, the consensus group did not feel surgical ablation was appropriate.”
Another “huge area” in the new consensus document, Calkins explained, was the issue of anticoagulation strategies. He said that the recommendations for anticoagulation pre-ablation, during ablation, and post ablation were “much more specific” than the first document. Regarding post-ablation, Calkins explained that they had taken a “very conservative approach.” He said: “If patients have significant risk factors for stroke, the presence or lack of atrial fibrillation does not alter the need for anticoagulation.” Importantly, the consensus document now advises that the risk of stroke is assessed with the CHA2DS2-VASc score (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, prior stroke or transient ischaemic attack, vascular disease, age 65–75 years, sex category) as well as the CHADS2 scoring system. It also reviews the new anticoagulants.
A third important change is that the document, in terms of clinical trial consideration, now has 53 new definitions. Calkins said: “Lots of things have been defined that have not been defined before. These were brought to us by the FDA, they said: ‘we need a definition of a failed cardioversion’ etc. so all of these things were defined.” One definition that has not changed is the classification for freedom of atrial fibrillation, which remains as being “freedom of atrial fibrillation, atrial flutter, and atrial tachycardia of more than 30 seconds recurrence after a three month blanking period”.
Concluding his preview of the consensus document, Calkins said: “This consensus document is really up to date and is a highly referenced review that 45 of your colleagues have spent a lot of time working on.”