Has AF ablation reached first-line status?

May 13, 2012 12:09 EDT

Rhythm-control drugs for atrial fibrillation leave a lot to be desired. In too many cases they fail to control the rhythm, cause undesirable side effects, or worse yet, create harm. Thankfully, AF patients have other options. For the past few years, the evidence base supports the role of catheter ablation in patients who have done poorly with medicines.

But has catheter ablation progressed enough to offer it as a first-line therapy? What about scenarios like this one—common in my practice?

He's tried to ignore the recurring paroxysms of irregular rapid rhythm. He's stopped running, which was his passion and his therapy. Now he's in your office seeking treatment for paroxysmal AF. On exam, his heart rate beats powerfully at only 42 times per minute. His ECG is normal—but that rate is so slow. He's given it time, cut out caffeine and alcohol, and still the episodes haven't stopped. This patient, this person, perhaps this friend, wants his life back. He asks you for help.

The question is: Must we follow the North American expert task force guidelines, which call for trying an antiarrhythmic drug before ablation? Or, should we favor the more lenient European guidelines, which allow us to offer catheter ablation as first-line therapy?

European or American, which is the best approach? (Ah, we could ask this for so many problems. Let's stick with AF here.)

An important multicenter study presented this week at HRS supports the notion that AF ablation (pulmonary vein isolation [PVI])—as a first-line therapy—has made the transition to the front line.

As summarized nicely by Steve Stiles on theheart.org, the RAAFT 2 (Radiofrequency Ablation vs Antiarrhythmic Drugs as First-Line Treatment of Symptomatic AF) trial demonstrated that low-risk symptomatic patients with AF (87% paroxysmal) treated with standard catheter-based PVI had less AF and fewer complications than did those treated with AF drugs.

The less-than-ideal success rates of both treatments speak to the challenges of treating AF. Using the overly strict definition of procedure failure (just 30 seconds of AF), 55% of patients treated with ablation had recurrence vs 72% in those who took AF drugs. So even though—by strict definitions—the ablation failed more than half the time, it looked far better than AF drugs.

On safety, ablation looked superior as well. Adverse events occurred in 7.7% of patients who had ablation compared with 19.7% of those treated with medicine. At first glance, this difference makes ablation look far safer. It's important to note that many of the drug-treated patients had adverse events that weren't quite as adverse as tamponade or stroke. For instance, drug-induced widening on an ECG and an episode of atrial flutter were counted as a safety event. But still, in total, we can at least say the safety of ablation compared favorably with drugs.

Although preliminary, this study will have a significant impact. The boat was already turning, but now there's a strong tailwind. Remember the evolution with paroxysmal supraventricular tachycardia (PSVT) ablation more than a decade ago: at first, ablation was only offered to patients who failed drugs, but soon, ablation evolved enough that randomized trials clearly demonstrated it as superior. The pattern with AF looks similar. AF doctors on the front lines of clinical medicine have already begun offering ablation to selected patients. With the results of RAAFT 2, this commonsense approach now has an evidence base.

Another message from RAAFT 2: As demonstrated throughout electrophysiology history, membrane-active antiarrhythmic drugs have never worked well. AF drugs are not without significant risk. RAAFT shows this beautifully. So does this mental image:

Imagine the runner, cyclist, or farmer out there in the field, in the heat, sweating, pushing himself physically. Now, imagine that same patient on flecainide.

Some cold water for ablation fans: First, these results come as an abstract, not as a published article in a peer-reviewed journal. Another important consideration is that AF ablation during the trial was performed at highly experienced centers. This is a huge distinction. Point-to-point RF ablation of AF requires tremendous skill and comes only with experience. And it's not only the experience of the operator that counts; it's also the experience of the center. AF ablation is a team sport. Its learning curve winds upward for a long time. Whether RAAFT 2 data apply to less-experienced centers—common in the real world—is debatable. I doubt low-volume centers could demonstrate similar results.

Let's finish with the big picture. The results of RAAFT 2 add more information to an already-complex decision-making process. Until the magic of Dr Narayan's FIRM ablation becomes mainstream, AF ablation remains a daunting challenge. It is our responsibility, therefore, to guide AF patients through this sea of choices. Always important is the doctor-patient relationship, but never more so in cases when life-threatening therapies are used for non–life-threatening diseases.

The treatment of AF—what a great race to be toiling in.

JMM

Morillo C, Verma A, Kuck KH, et al. Radiofrequency Ablation vs Antiarrhythmic Drugs as First-Line Treatment of Symptomatic Atrial Fibrillation: (RAAFT 2): A randomized trial. Heart Rhythm Society 2012 Scientific Sessions; May 11, 2012; Boston, MA. Abstract Abstract LB02-1.