AF Ablation 301: A quest for clarity…

After reading this Washington Post story on the complexity of AF ablation decisions, I wrote, and wrote, and it just didn’t come together well.  Not well enough to do the topic of AF ablation justice.  Then this thoughtful email came.

My question: How does a patient have even the faintest idea whose advice is better for him/her individually? The only solution I can think of is to somehow have complete trust in my physician, his/her knowledge of a-fib, understanding of my circumstances, etc., etc. That’s all but impossible in light of the way medicine is delivered today.

So, short of complete trust in a physician, how does a patient weigh and measure the various factors to come up with a reasoned decision? Is there a checklist of factors to match against each other? I’m thinking of stuff like age (in what circumstances is sooner NOT better than later?), AF’s progressive nature, risk of stroke, degree of stretch damage, ablation success rate, waiting for new, possibly more successful treatments, heart rate control as a measure of success w/ medication, paroxysmal vs. persistent, the list goes on. Are some factors so compelling that you would routinely recommend one course or the other?

So, I will try again, attempting to clarify my thoughts on AF ablation, as an answer to the above questions.


AF ablation background:

Atrial fibrillation treatment could not be more complicated.  AF affects a wide variety of patients, in a myriad of ways, ranging from asymptomatic to incapacitating.  AF can be intermittent, persistent and permanent, and success in ablation parallels this continuum. Stroke risk with AF is determined by the 6 point CHADS score, where a point is assigned for Congestive heart failure, High blood pressure, Age>75, Diabetes, and two points for a previous history of Stroke.  A higher score implies a greater stroke risk, and a score above 2 clearly indicates benefit to the blood thinner, warfarin.  Read more here.

In the lower risk AF patient, the real dilemma in choosing AF ablation is that its complications can be catastrophic while the disease is rarely so. “AF is not a life-threatening disease, don’t make it one,” is advice I received years ago, from a squisher, no less.  However, not only can AF increase the risk of heart failure and stroke, but it often markedly degrades one’s quality of life.  Even patients with seemingly asymptomatic AF score lower than their sinus rhythm peers on quality of life surveys.

Consider also that AF drugs are rarely effective in the long-term.  Even when drugs are partially effective, the side effects are often worse than the AF symptoms themselves. Fatigue, shortness of breath, and lower exercise capacity are both symptoms of AF and the most common side effects from rhythm drugs. Moreover, not only are AF drugs associated with nuisance side effects, many have significant dangers, including QT-prolongation, which enhance the propensity to more malignant ventricular arrhythmias.

AF ablation specifics:

AF ablation encompasses a variety of techniques, but most commonly involves using a series of isolated radio-frequency lesions (burns) to isolate quadrants of the left atrium. Using the image of the United States map as the left atrium, consider the four pulmonary vein areas as Maine, Florida, Seattle and LA.  Ablation aims to isolate these problem areas by creating lines of electrical block with dot-like burns.  It takes many dots to create a singular line, and if AF originates from Kansas, our lines will have no effect.

Here’s what a typical lesion set looks like…(with a common left PV)

Early reports of near 90% AF ablation success rates were clearly exaggerated. The widely accepted present-day rate of ablation success is 60-80%.  Many patients require two procedures because our electrical lines of block are frequently impermanent. Although the complications of AF ablation are infrequent (around 1-5%, depending on who you ask), they are very serious and frequently life-changers:

• Perforation of the heart in a patient on blood thinner.
• Stroke.
• Stenosis of a pulmonary vein resulting in permanent damage to the lung.
• Phrenic nerve injury resulting in diaphragm paralysis.
• Esophageal damage frequently resulting in death.
• Valve damage.
• Heart attack.
• Damage to the leg blood vessel.
• High exposure to radiation.

In 2010, AF ablation is better, for many reasons: (here are four)

• Few of us EPs are doing the procedure, as unlike the thirty-minute ICD implant, AF ablation is not a money maker.  It takes hours, makes your shoulders, feet and back ache and sadly it pays nearly the same as a simple 45 minute ablation.  (Degree of difficulty is irrelevant to CMS.)  AF ablators do it for the gratification and thrill of curing an awful disease, not for the money.
• Fewer operators mean more case volume for those of us who accept this challenge.  More cases makes any operator better.  Ask Dr Gawande about this. Comfort with the trans-septal needle, the location of the actual origin of the pulmonary veins, knowledge of the fragility of the left atrial appendage, and the danger of burning aggressively near the esophagus are just a few of the specifics that make experienced operators better.
• Experience with ablation failures also helps guide AF doctors. Learning when to say ablation is not the right choice is incredibly important.
• Three dimensional mapping systems have advanced to the point where strikingly accurate geometric maps can guide catheter manipulation without the burden of radiation exposure.  It is not uncommon for an AF ablation to have less xray exposure than an ICD implant.  Precise knowledge of the anatomy not only enhances that particular patient’s safety, but it also provides an incredible educational experience to the operator.