Dr John Mandrola practices cardiac electrophysiology in Louisville, KY. He finished training at Indiana University in 1996. His practice encompasses catheter ablation, including an eight-year experience with AF ablation, device implantation, and consultative EP. Outside of the EP lab, Dr Mandrola's two hobbies include competitive cycling and writing. He has maintained a medical, fitness, and cycling blog, Dr John M, for the past two years.
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AF ablation: What are we doing?Feb 17, 2012 14:45 EST
"Atrial fibrillation isn't an immediately life-threatening disease; don't make it one."
So says a good friend, cardiology colleague and master of the obvious.
I wonder about AF ablation. Don't you? Would you have AF ablation? Would you wonder about the long-term effects?
What about the rightness of poking a needle across a beating atrial septum? What of the idea of making 50 or more burns in the delicate left atrium? And those lines?
Yes, I often wonder what we AF ablationists are actually doing?
Are we curing AF? Are we changing the natural history of the disease?
Or . . . is AF ablation akin to placing stents for chronic coronary disease: just a big procedure to reduce symptoms, without improving real outcomes? Similarly, as stents do with their need for antiplatelet drugs, does AF ablation create yet another disease: a poorly contractile left atrium for one, asymptomatic brain lesions, another.
But the treasure of AF ablation is so grand. Freeing patients from the shackles of AF (or AF drugs) feels so good. I tell AF patients this all the time: "I realize that you are the one most invested in the outcome of AF ablation, but I am right behind you."
As heart doctors, our self-esteem demands that we succeed. But AF makes it pretty damn tough. I call this struggle, the AF quandary. Few AF patients can stand (or are best served with) no treatment. Yet sometimes our efforts make matters worse. Blood-thinners worsen bleeding, medicines cause side effects or worse, proarrhythmia, and ablation exposes patients to serious risk.
For the moment, let's focus on the most aggressive treatment of AF—catheter ablation.
A big procedure should have clear goals. Are we aiming to improve survival (acute PCI for heart attack) or just improve quality of life (elective knee replacement)? Or both?
AF patients need both goals addressed. I believe if questioned skillfully, most AF patients will describe living a lower quality of life since the disease struck. It's not just aging; it's the AF. But we also have to consider the long-term risks of AF. Population data, like the Framingham studies, clearly associate AF as a risk factor for stroke and earlier death over the long term.
So wouldn't it be cool if AF ablation did both: alleviate symptoms and lower the risk of stroke and early death? Common sense suggests that it should work this way. The thinking goes: AF ablation eliminates AF, and sinus rhythm means no clots or tachycardia-mediated cardiomyopathy.
Unfortunately, the paradigm of (medically rendered) rhythm control didn't work. The AFFIRM trial showed that maintenance of regular rhythm was associated with lower mortality, but this benefit was neutralized by the negative effects of AF medicines.
But we can all agree that AF ablation works better than meds. Numerous studies show that patients treated with AF ablation, when compared with AF patients on meds, have fewer AF episodes and report higher quality-of-life scores. Yet these studies shed little light on how (or if) AF ablation changes the natural history of the disease.
Ablation naysayers point to these three common post-AF ablation observations:
- What about the issue of "success?" I hear this often: "Doc, these short episodes are nothing. I feel great. . . . Thank you. I'm good." Does lowering AF burden and improving symptoms equal better outcomes? Maybe not; recent recent data suggest even short episodes of AF may increase stroke risk.
- Changing the perception of AF. After ablation, patients may not feel AF in the same way. Some may still have long episodes but are no longer bothered by them. I know; it seems strange. I don't understand it either.
Patient: "Thank you. The ablation worked; my AF is gone. I feel normal."
Me: "You are in AF."
Patient: "How is that possible? I felt so bad with AF before, but now I feel great."
- The downsides of the burns. What are the long-term effects of ablation? The two that come to mind are small brain lesions on MRI scans (most of which resolve) and the possible decrease in LA systolic function. If the atria don't squeeze, what's the point of fixing AF? Although both constitute small risks, one has to remember that many AF patients are at low risk before ablation. Small risks may be amplified in low-risk patients.
Obviously, prospective randomized clinical trials are needed to answer these outcome questions. One such study, the CABANA trial, is enrolling AF patients now. Recruitment has been tough, because symptomatic patients want ablation, not drugs. Results will not be available for years.
What can we tell our AF patients now? Is ablation only to relieve symptoms?
As an AF ablation optimist, I think we are doing more than just relieving symptoms. Recent data hint that I may be right.
When Australian and British researchers looked back at outcomes from an AF registry of 1273 patients who had AF ablation, they found encouraging results. Compared with a group of medically treated patients and a hypothetical group of similar patients without AF, those treated with AF ablation had far fewer strokes and better survival. Freedom from AF after ablation lowered the stroke rate by 70%. Females, who typically fare less well with AF, did especially well with ablation. Using historical controls and registry data has important limitations, but these encouraging results align well with other recent look-back trials of AF ablation.
Although the picture is unfinished, a mosaic begins to take shape. As experience and technology make AF ablation safer and perhaps more effective, it becomes plausible to believe in the possibility that our hard-won ablation skills may change the course of the disease.
For now and well into the future, the treatment of AF remains challenging. Getting to the best results for our AF patients requires using all the tenets of good doctoring: knowing the disease, communicating the options, involving the patient in the decision, and then skillfully moving a catheter.