Highlights of the 2011 Boston AF Symposium

Over the past 16 years, the Boston AF Symposium has earned a reputation for excellence.  Dr Jeremy Ruskin, the meeting’s senior director and founder, squeezes more learning into three days than would seem possible.  It’s a mystery how he gets that many of Earth’s greatest AF-doctors to Boston in January.

Though this year’s edition coincided with a blizzard, I made it to the waterside conference center just in time.

Here are a few highlights:

AF-Ablation news:

In ablating intermittent (paroxysmal) AF, the big story was that AF-recurrence rates after an initially successful ablation are way too high.  All AF-doctors are struggling with this reality, and we all hate that phone call form the post-ablation patient who has recurrent AF.   In most cases, AF comes back after ablation because the burns were not durable.  But why not?  Unfortunately, for this answer, we will have to wait. People have ideas but no one has definite answers.

Except, of course, Medtronic argues that they may own a better tool for ablating AF.

For the first time ever in adult ablation, freezing may have a fighting chance against burning.  Medtronic’s recently released cryo-ablation balloon catheter (Arctic Front) looked quite promising.  When the Stop-AF trial was released earlier this year, the primary concern of freezing in the left atrium was safety.  What I heard, from experts that I respect, like the outspoken Karl-Heinz Kuck from Hamburg, Germany, was that the feared complications of cryo-ablation–phrenic nerve injury and PV stenosis–can be largely avoided by simple technical maneuvers in the EP lab. I look forward to earning more about this new technology.

In ablating long-standing (permanent) AF, the major story was that there are far more questions than answers.  Perhaps the meeting’s most lively debate was on how best to ablate chronic AF?   The choices spanned the entire spectrum of aggressiveness: from the minimalist approach of the University of Pennsylvania group, who isolate the PV areas, any ancillary triggers and that’s it; through the stepwise Bordeaux approach which calls for PV isolation plus lines in the left atrium until AF organizes into something focal that can then be ablated; to the most aggressive, burn-every-left-atrial-signal approach advocated by the group in Austin Texas.

In the end of the ablation sessions, there were many questions and few answers:

• Are the minimalists burning enough?
• Are the aggressors burning too much?  (If the entire left atrium is ablated and cannot contract, then what good is sinus rhythm?)
• How can Dr Pappone be so successful?   Is there magic to be had in Milan?
• Is there a role for collaboration with cardiac surgeons?
• And of course, as it is every year, a voice from the distant microphone in the back of the hall asks Dr Natale whether he would undergo the extensive ablation that he advocates?  His answer is always the same: “…let me know how you feel about ablation when you get AF.”

Stroke prevention:

Stroke prevention in AF means dealing with blood clots that form in the left atrial appendage.  The LA appendage has nooks and crannies that, in the presence of a non-contractile fibrillating atrium, act as excellent sources of clot formation.  When these clots dislodge they often travel north to the brain and cause devastating strokes.  There are two ways to approach LA clots: with blood thinners, or exclusion of left atrial appendage.

Until this fall, the only medical option to prevent strokes in AF was warfarin. Now, in non-valvular AF, we have the novel new warfarin-substitute, dabigatran (Pradaxa).  It was surprising to hear that more than one expert suggested that all patients with non-valvular AF should be offered the new drug–even those doing well on warfarin.  That’s a tough call at the moment, but without doubt dabigatran looks like a potential blockbuster.

We also heard that Boehringer’s monopoly will not last long.  There are other blood thinners on the horizon.  Look for the Factor Xa inhibitors, rivaroxaban, apixoban and edoxaban, to be approved in the near-term.  In total, these new blood-thinners will eventually replace warfarin.  Thank goodness.

Another cool feature of the Boston AF symposium is that it always looks far into the future.  For stroke prevention, the future may include devices that occlude, tie-off and otherwise remove the left arial appendage.  Co-course director and incessant tinkerer with cardiac devices, Dr Vivek Reddy showed some dazzling examples of LA appendage isolation devices. He always shows such devices, but this year, it looked like some of these gadgets are approaching prime-time, or said another way, something I could do.

Miscellaneous Notes:

• There were no words uttered on dronedarone.  Not even from those who touted it so highly the past few years, and not even after the two cases of liver failure were reported on Friday.  The ancient drug, Mexiletine, was mentioned during a case presentation, but not dronedarone.  Silence.
• Dr Maurits Allessie–of AF begets AF fame–has presence.  It was cool to be in the same room with a legend.  For that matter, though I can’t always understand them, the basic scientists are a refreshing bunch who add a great deal of credibility to this meeting.
• Eric Prystowsky continues his run as the most entertaining speaker.  His irreverence towards epidemiologists, statisticians and non-clinician scientists, especially those responsible for the recently published and now infamous JAMA ICD article, was very well received.  He makes you grin and teaches at the same time.

I am already looking forward to next year’s conference.

The year in AF will be exciting.  Look for reports on our actual experience with the cryo-balloon, approval of another blood thinner to compete with dabigatran, and perhaps some more information on increasing the durability of RF lesions.

JMM