John Mandrola


May 08, 2014

Rather than report on one study, I thought it best to provide a roundup of the many themes from the first day of Heart Rhythm Society 2014 Scientific Sessions in San Francisco. I'll offer a brief synopsis of the plenary session and then launch into some of my favorite topics from the evening poster session.

The Plenary

The meeting began in earnest with a plenary session that asked electrophysiologists to consider the digital future of medicine. This is hard on heart-rhythm doctors. We like wearing dark suits and red ties; we like fixing things with devices; we like yes/no problems; and we like being in charge. The idea of harnessing social networks and counseling (rather than dictating to) empowered doctorless patients gives us palpitations.

To give you the flavor of the plenary session, it's useful to mention just the titles of the speakers. Dr Leslie Saxon is a professor at the University of Southern California Center for Body Computing. David Pogue, a former New York Times technology columnist, now leads the flourishing website Yahoo! Tech. Dr Eric Topol is Eric Topol. Just kidding. He is author of the Creative Destruction of Medicine (and editor in chief of Medscape). Dr Silvia Priori is both the director of molecular cardiology and EP laboratories at Fondazione Salvatore Maugeri in Pavia, Italy and a leader of the cardiovascular genetics program at New York University. You see what I mean? Body computing, technology, apps, doctorless patients, and using DNA to treat disease—these are no small things for doctors who like to burn arrhythmias they don't understand.

David Pogue summed up the woeful neglect of analog medical practice by reminding us of the not-so-long-ago movie-rental procedure. He asked the audience to walk in the shoes of the instant-gratification generation. What would young people think of the idea of getting in a car to drive to a movie rental store, to rent an actual disc, to be used in a hardwired machine? In the era of Netflix and Amazon, this notion is hardly imaginable. But yet this is exactly what patients do: they get in a car, to drive to a doctor, to get treated on others' terms, and then, maybe in the best case, they can view their medical records on paper. Yes, indeed, woeful fits.

On to the posters . . .

Of Course, It's All Connected—Atrial Fibrillation, Inflammation, and Endothelial Dysfunction

If your practice is like mine, you see a couple of patients each year with very new-onset AF and stroke. Why would this be? These are often low-risk patients who had short-lived AF. Old thinking had it that left atrial clot took days to occur.

The prolific group of researchers from Adelaide, Australia (Geetanjali Rangnekar, lead author), presented data showing that new-onset AF associates with measures of cardiovascular health.[1] They measured various biomarkers in 66 patients (n=23 AF, n=43 normal controls). AF patients had evidence of significant endothelial dysfunction, inflammation, and remodeling. These findings nudge us to consider AF as more than just a disease of disordered rhythm. Although a small study, the findings begin to explain why aggressive lifestyle measures reduce AF burden. I once read somewhere that regular exercise, good nutrition, and sleep without hypoxemia improves health. (Think of these findings when reading the brain-health and referral-bias studies mentioned below.)

Decision Making in ICDs: Seeing the Long View

Dutch researchers (Dr Aafke van der Heijden, lead author) from Leiden University put themselves in the shoes of the ICD patient. They asked the important question: "What can a patient who is referred for an ICD expect?"

They provided 12-year follow-up of 3055 patients implanted with an ICD at their hospital. They reported 55% of all ICD recipients had died, and only 50% of those implanted for primary-prevention indications received an "intervention" for a potentially life-threatening arrhythmia. It was 73% for those implanted for secondary prevention.

I like this study because it places decision quality right before our eyes. We have known, and sadly, some clinicians choose to ignore, that most patients we implant with an ICD are exposed to all the risks and do not ever benefit from the device—ie, nothing happens. The Dutch investigators confirm that this finding persists for 12 years. More important, though, is the reminder that death is not optional. Getting away from the mind-set of death avoidance would be a good thing for all caregivers.

The Human Body, Especially the Heart And Vessels, Are Durable

Cleveland Clinic researchers (Dr Yoaav Krauthammer, lead author) bravely performed histologic studies of the retained "cuffs" that accompany extracted leads.[2] They were after the "untold microscopic" story. The results were sobering: 22 of 75 (14%) leads had transmural segments of vein. That's a sterile medical-speak way of saying the entire vein was torn away with extraction. Remarkably, only one major complication occurred in their series of 75 patients. The authors concluded, "Venous injuries during extraction are common but often not recognized clinically."

Okay . . . that's a legit, but safe, conclusion. I'd offer two other big messages: first is that lead extraction is no small thing and should be done only when necessary—not just because "one has a hammer." The other message speaks to the durability of the human body, specifically the cardiovascular system. Think of the things we "get away" with in electrophysiology.

AF Ablation in Hypertrophic Cardiomyopathy Is Challenging

In a recent review of the 2014 AF treatment guidelines, I asked whether other groups had experienced similar difficulty in ablating AF in patients with hypertrophic cardiomyopathy (HCM). Two posters confirmed my findings.

Beth Israel researchers (Dr Elad Anter, lead author) reported a series of 32 AF patients with HCM who had undergone pulmonary-vein isolation (PVI).[3] They compared this group with a standard cohort without HCM. Patients with HCM had longer procedure times, more ablation, more postprocedure antiarrhythmic drugs, and only a 48% arrhythmia-free survival—vs 68% in non-HCM patients. The authors concluded PVI has limited efficacy in patients with HCM and requires consideration for patient selection.

The Cleveland Clinic team (Dr Mohamed Bassiouny, lead author) reported on 119 HCM patients who underwent catheter ablation (n=73) and surgical ablation (n=46).[4] Follow-up was two years. Repeat ablation was done in 61% of the catheter-ablation group and 26% of surgical-ablation group. Success rates were 40% for catheter ablation and 41% for surgical ablation with multiple procedures. They offered a similar conclusion: Nonpharmacological treatment of AF is feasible in HCM patients; however, long-term success is lower than previously published.

Brain Health After AF Ablation

One of the least talked about, but to me, most worrisome, downsides of AF ablation is the matter of cerebral injury. It is well known that if one does MRI brain scans following AF ablation, many patients will have "white spots," which we benignly call subclinical cerebral ischemia (SCI). In most cases, these spots resolve over time, and the thinking among most ablationists approaches the no-harm-no-foul rule. This sort of mind-set is okay from the doctor's perspective, but patients may feel differently. Concussions are a different disease, but the lesson learned pertains to the danger of repetitive insults to the brain. Surely we can agree postprocedure white spots count as an insult to the brain.

A Mayo Clinic study, which looked at both anatomy and function of the brain after left heart procedures, added to the worry of the white-spot problem.[5] In a small series of patients who underwent AF ablation (n=25) and LV ablation (n=3), this group found silent cerebral lesions in 29% of patients. More worrisome was that 44% of patients in this series also had cognitive decline measured on psychomotor tests one to three days' postprocedure. Yes, it's a little early after the procedure to be measuring cognition, but lead author Dr Malini Madhavan told me they are planning longer-term follow-up.

Two other posters suggest the periprocedure anticoagulation regimen plays an important role in brain protection surrounding AF ablation.

A group of researchers from Bad Neustadt, Germany (Thomas Deneke, lead author) studied the effect of anticoagulation protocols in 113 patients who underwent various types of AF ablation (cryoballoon, RF, multielectrode circular ablation with a pulmonary vein ablation catheter) on the presence of cerebral ischemia on MRI.[6] They found the strategy of uninterrupted warfarin superior (17% of patients with lesions) to interrupted novel anticoagulants (44% of patients with lesions.)

The group of researchers led by DrLuigi Di Biase (Dr Andrea Natale, senior author) reported similar data with periprocedural rivaroxaban.[7] In a series of 49 consecutive patients with persistent AF, patients were randomized to either uninterrupted rivaroxaban or rivaroxaban held for 24 hours before and after the procedure. The latter group had bridging with low-molecular-weight heparin. No patient in the uninterrupted strategy had a cerebral lesion, whereas seven of 24 patients in the interrupted strategy had silent cerebral lesions.

These data urge us to think hard about easy fixes for systemic diseases like AF. Remember: thinking is what makes us human.

Referral Bias Among Electrophysiologists: If You Have a Hammer . . .

I realize this sounds crazy. Electrophysiologists could not possibly be biased. Back home, I am often accused of being too conservative with AF ablation. Some of my colleagues say I am biased against procedures. Perhaps this is what drew me to my favorite poster of the evening session:

A group of Canadian researchers from McMaster University (Dr Naeem Al-Shoaibi, lead author) performed a unique analysis of the referral patterns of five electrophysiologists in their group.[8] Three of the electrophysiologists ablate AF and two do not. They set out to measure whether or not that fact mattered in the referral of patients for ablation. Their series included 128 patients seen in an outpatient clinic over 10 months. In all the usual baseline measures (eg, CHA2DS2-VASc, prior drug failure, and cardioversions), patients seen by nonablating EP docs were similar to those seen by ablating EPs. Yet patients seen by an ablating electrophysiologist were four times more likely to be referred for ablation (42% vs 9%). The authors rightly conclude "that physician bias has a major impact on clinical decision making and that there is a need for tools to make clinical decisions more consistent."

Hear, hear for decision quality!

See you again tomorrow.



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