A year-end review of 2012: Top 10 stories in EP

Dr John Mandrola

Disclosures

January 02, 2013

These stories struck me as the most notable of 2012. Let's start with the positive and optimistic.

1. AF ablation: On the cusp of something big

The most upbeat—thrilling even—story of 2012 was the news that ablation of AF might become dramatically easier and more effective. Focal impulse and rotor modulation (FIRM) ablation transforms ablation of AF from anatomic to targeted. This is huge!

For more than a decade, AF ablationists have struggled to durably ablate in the left atrium. Enlightened AF patients often ask: How do you know where to ablate? Can you see the area causing the problem?

We don't. And, no, we can't see the area.

Enter FIRM ablation. Using information collected from a multielectrode basket catheter placed in both atria during AF, a computer software algorithm (the secret sauce, if you will) identifies area(s) of focal impulses or rotors that are critical for AF perpetuation. According to the Conventional Ablation for Atrial Fibrillation With or Without Focal Impulse and Rotor Modulation  (CONFIRM) trial, targeted ablation at these sites can not only slow or terminate AF, but more important, such focal ablation leads to improved long-term success rates.

Perhaps this is why Dr Sonny Jackman came to the mike at the Heart Rhythm Society (HRS) 2012 annual meeting after hearing the CONFIRM data and uttered the quote of the year: "This work could turn the AF-ablation community upside down."

I know what you may be thinking: we have heard stories like these before. Criticism of FIRM ablation was spirited. It relies on a mysterious proprietary computer program (RhythmView System,Topera Medical), and CONFIRM was a single-center study.

Concerns over the single-center nature of CONFIRM were answered when other electrophysiology (EP) labs involved with FIRM recently published similar findings to those of Dr Sanjiv Narayan. More than 20 abstracts involving FIRM have been submitted to HRS 2013, and an upcoming publication in Circulation: Arrhythmia and Electrophysiology is forthcoming, says a physician familiar with the matter.

2. Freezing AF gains ground in the real world

Until FIRM ablation becomes mainstream, current-day AF ablation centers on durable electrical isolation of the pulmonary veins (PVs). This can be accomplished with fire or ice. Using heat, point-to-point ablation of the PVs took years of experience and hundreds of cases to learn. Even the most skilled centers report redo-ablation rates as high as 40%. The pesky problem is gaps in conduction. It's hard to draw lines with dots. What's more, RF ablation done far from the PV orifice—or in other areas of the left atrium—creates the risk of damage to atrial mechanical function. Athletic AF patients are greedy; they want sinus rhythm and good mechanical left atrial (LA) function.

Enter cryoablation. With the release of a second-generation balloon, PV isolation with cryoenergy has made inroads in the real world. After years of experience with RF ablation, I have now done a handful of cases of cryo. Here was my thinking: as a paroxysmal AF patient myself, I would strongly consider having cryoablation. The durability of PV isolation may be superior; the risk of damaging LA mechanical function is lower; and, in skilled hands, the complication rates are minimal. The PV isolation that comes with a single freeze is impressive. Combining intracardiac ultrasound has led to lower fluoroscopy times and smaller contrast loads. I'm not alone. Many of my colleagues are learning cryoablation.

3. ICD implants down

While advances in AF ablation are the most upbeat story of 2012, the fall from grace of the implantable cardioverter defibrillator (ICD) is the biggest EP story of the year. It seemed like just yesterday when all patients with low ejection fraction needed an ICD. Oh, how times have changed—for the better!

Let's explore some of the possible explanations for the demise of the ICD. Doing so will take us to a number of noteworthy stories.

In January 2012, in a Perspective piece in the New England Journal of Medicine, Drs Alfred Buxton, Daniel Kramer, and Peter Zimetbaum urge implanting doctors to consider relooking at patients' indications—and their wishes—at the time of ICD battery depletion. Not only are the specifics important here—ie, of course we should reevaluate the need for continued ICD use—but also, there is this disruptive notion: that subspecialists be gatekeepers for expensive and invasive therapy. In the future, implanting doctors must be more than just skilled technicians. We must also be capable of talking with patients about their—not our—goals of care. For who knows better about what an ICD can and cannot do?

Perhaps ICD therapy is seen differently now because voices of reason are rising above a whisper? Again, Dr Buxton writes perhaps the best EP-related article of the year. In a paper subtitled "The quest to identify patients most likely to benefit," heurges clinicians to ask: What would a patient's mortality be with and without an ICD? Pause for a second here. This is hugely good advice for all heart doctors!

Dr Buxton points out that 2012 saw the publication of numerous risk models to predict mortality in ICD recipients. The gist of these models suggests a much narrower "sweet spot" of ICD therapy. As cost concerns rise and our population grows older and sicker, considering comorbidities and patient preferences before recommending an ICD is a timely topic.

Although these were refreshingly smart words, they were nary more than a whisper. The loudest voice suppressing ICD implants came from the US Department of Justice (DOJ) investigation. This was serious business. 2012 was the year that electrophysiologists met with legal departments of hospitals. I even learned of the existence of large consulting firms with huge budgets that were born to help hospitals navigate government investigations. Who knew such organizations existed? Drs Jonathan Steinberg and Suneet Mittal recapped their sobering experience with the DOJ. It was a very muted and calm portrayal. Other electrophysiologists had stronger feelings.

The DOJ investigation had a chilling effect on ICD referrals. It's led many hospitals to mandate preimplant audits. In some ways, this is a good thing, as it encourages adherence to the evidence base. But as all real doctors can attest, the gray area of clinical medicine cuts a wide swath. Not all patients fit nicely into the national coverage decision for ICDs—especially since the criteria were last updated in 2005.

4. Riata/Durata

The scab from the Medtronic Sprint Fidelis wound was barely formed when we crashed again. The St Jude Riata/Durata mess knocked that scab off and cut even deeper. Writing in Heart Rhythm in September, Dr Michael Sweeney captured the essence of recent hardware recalls well:

[T]he [ICD] equipment has acquired the taint of unreliability, the patients suffer, and much time is spent by well-meaning implanters apologizing to patients for things that went wrong with the best of intentions. It is a bad story in bad times: megarich medical-device companies, faulty equipment, and skittish patients who are afraid of dying and afraid of lifesaving therapy. "Why would I want one of those? I feel fine and I heard they have a lot of recalls." It is hard to argue with that reasoning.

It's also hard to tell you anything that you don't already know about Riata/Durata. I'll just add this: hardware problems with ICDs, especially this one, emphasize the important concept that ICDs should never be equated with insurance policies against our mortality. Oh, and one more thing . . . I'm really nervous about Durata.

5. ICD programming: Less is more

Let's move to some good news about ICDs. If we are going to implant an ICD, it makes sense to maximize benefit and minimize harm. After the perioperative period, the most likely adverse event from an ICD is a shock. It's now well accepted that both appropriate and inappropriate shocks are associated with higher mortality.

The Multicenter Automatic Defibrillator Implantation Trial—Reduce Inappropriate Therapy  (MADIT-RIT) investigators studied the importance of ICD programming strategies. They randomized 1500 patients indicated for either a primary-prevention ICD or cardiac-resynchronization therapy (CRT) device to conventional programming, delayed therapy, or a high-rate strategy. Compared with conventional programming, the delayed and high-rate strategies resulted in fewer shocks and improved mortality.

These were striking findings. The idea that delivering less therapy reduces mortality highlights the value of a less-is-more approach. I love the idea that we can decrease the burden of ICD therapy. Look for these findings to be quickly incorporated into ICD guidelines. They have already changed how I program ICDs.

6. CRT continues to impress

For electrophysiologists, there are few things more impactful than the superresponse from a CRT device. Sure, it's hyperbole; but the parable of Lazarus comes to mind.

In 2012, there were a three notable tends and stories pertaining to CRT.

6a. Expanding indications for CRT  

The Biventricular Versus Right Ventricular Pacing in Patients with Left Ventricular Dysfunction and Atrioventricular Block (BLOCK HF) trial demonstrated what electrophysiologists have come to know—namely, that in patients with AV block who will require RV pacing, the small incremental risk of implanting a CRT (rather than a dual-chamber device that may need to be upgraded later) is worth it. My colleague, Dr Edward J Schlosshas this nice recap .

In October, CRT therapy was highlighted in a focused update of the ACC/AHA/HRS guidelines for device-based therapy. Left bundle bunch block (LBBB) figures strongly in the guidelines.

6b. Predicting CRT response  

Many years ago, when I first taught myself to implant a CRT device, the major issue was getting a non–over-the-wire LV lead into a useful vein. That's rarely a problem now. The conundrum is predicting which patient will respond. First, we aren't even sure how to measure a response. Is it an echo response or clinical response? And then, for that matter, what is a clinical response?

Second, we learned that women with nonischemic disease, typical LBBB, and QRS duration >150 ms are more likely to respond. The trouble is that we have all seen nice responses from men with ischemic disease. It's the same idea with QRS duration between 120 and 150 ms. Although retrospective studies suggest this range of QRS is less likely to respond, we have all seen patients in this category improve. A refreshing aspect of CRT is just this: that we don't have all the answers. Sometimes you just have to tell the patient that you don't know what will happen.

6c. AV node ablation helps in AF

The final piece of news on CRT worth mentioning is the importance of maximizing the percentage of true biventricular pacing. This is critical for patients with AF. Australian investigators put together a powerful meta-analysis showing that combining AV node ablation with CRT improves clinical outcomes, including mortality. Although the minimalist in me cringes about the permanence of AV node ablation, there is no doubting its benefit when added to CRT in patients with AF and slick AV nodal conduction.

7. Novel anticoagulants: A year for rivaroxaban

2012 was the year that novel anticoagulants picked up momentum. Just a week ago, apixaban finally got the nod from the FDA . Surely apixaban will be a big story in 2013.

But this was really the year of rivaroxaban. Although it was approved for stroke prevention in AF in 2011, rivaroxaban gained the confidence of clinicians in 2012. Bolstered by its once-daily dosing and lack of gastrointestinal side effects, rivaroxaban contrasts nicely with dabigatran—an agent beaten mercilessly by inaccurate "bad-drug" ads in the mainstream media.

Ironically, the year's most influential trial in anticoagulation may not relate to arrhythmia. The Einstein PE trial showed that rivaroxaban was at least as effective as low-molecular-weight heparin and warfarin in the treatment of pulmonary embolism (PE). Most important, efficacy was accomplished with lower bleeding rates.

Let me explain why a PE trial was so influential. The knock against rivaroxaban was its margin of victory over warfarin. Where dabigatran and apixaban were found to be superior to warfarin, rivaroxaban was merely noninferior. In other words, at the dose approved for AF, clinicians worried about its anticoagulant potency. Is it enough?

But we all know about PE: here is a disease that requires significant anticlotting measures. So, when rivaroxaban proved favorable against PE—albeit at a higher dose—clinicians could believe.

Obviously, we have a lot to learn about the novel anticoagulants. The dabigatran experience taught us to pay close attention to renal function, patient frailty, and adherence issues. We also need to hear more about the periprocedural safety of rivaroxaban and apixaban. It's mostly settled that periprocedural dabigatran is reasonably safe, but data are lacking for the two newer agents.

8. Gender-related issues . . . are real

It's hardly stirring to suggest that women are different from men. Until 2012, however, electrophysiologists rarely made much distinction. After reporting our experience of AF ablation, I'm now convinced this is a mistake.

Two gender-related themes emerged in 2012. Publishing in the Journal of the American Medical Association , Canadian researchers confirm female gender as an important risk factor for stroke in patients with AF. That female gender increases stroke risk is only one of many reasons to favor the CHADS-VASc score in predicting stroke risk in AF. (Case in point: a 67-year-old female with vascular disease has a CHADS-VASc score of 3 but a CHADS score of 0.)

The second important gender-related topic involves ICD therapy. Two trials were published in 2012 (here and here) that shed light on how gender interacts with the ICD. Compared with men:

  • Women are much more likely to suffer complications from an ICD implant, including perforation and lead dislodgement.

  • Women are less likely to receive appropriate shocks.

  • In the months after implant, women have a higher risk of readmission for heart failure and death from any cause.

Why are there such striking differences? Is it referral bias? Or delayed therapy in women? Or, as suggested in this must-read editorial by Drs Pamela Douglas and Lesley Curtis , is it simply biology?

9. Aspirin use in AF falls from grace

At the European Society of Cardiology (ESC) 2012 Congress, two important news items concerning the use of aspirin for the prevention of thromboembolic complications in patients with AF came to light.

The first was the release of the 2012 focused update of the ESC treatment guidelines for AF. Here, the lead item emphasized aspirin's poor efficacy and bleeding complications. European guidelines recommend aspirin for stroke prevention only in AF patients who refuse to take oral anticoagulants. This departs significantly from North American guidelines.

The second aspirin-negative study addressed the issue of stroke prevention in patients with recent coronary stents. The What is the Optimal Antiplatelet and Anticoagulant Therapy in Patients with Oral Anticoagulation and Coronary Stenting  (WOEST) trial showed that in patients already on an oral anticoagulant who undergo stent placement and double therapy with clopidogrel and warfarin is superior to triple therapy with aspirin, clopidogrel, and warfarin. Again, dropping aspirin led to better outcomes.

10. Honorable mentions

Are MRIs safe in patients with cardiac devices?

Despite what one device company suggests, it is not necessary to have an MRI-safe pacemaker to safely undergo an MRI. The MagnaSafe registry reported no important safety issues when patients with cardiac devices underwent MRI scans. Good luck incorporating this in real-world radiology departments.

Be alert for sleep disorders

Sleep disorders, primarily obstructive sleep apnea (OSA), are greatly underrecognized and increasingly important factors in the treatment of arrhythmia. OSA is associated with atrial remodeling, increased risk of AF recurrence postablation, and worse outcomes after ICD implant. I can't vouch for your geography, but in mine, obesity-related OSA is a huge problem.

The iPhone ECG

In December, the FDA cleared the AliveCor IPhone ECG for sales to medical professionals. This amazing device offers a glimpse into the future—a future where one's rhythm can be acquired, recorded, and then electronically sent with a smartphone.

Thanks for reading. Feel free to add your choice for this year's top story in the comments.

JMM

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