July 11, 2014
4 min read

Top 4 lessons learned from HRS 2014

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Some of the lessons offered by the Heart Rhythm Society’s 35th Annual Scientific Sessions pertained to exciting new innovations, some pertained to patients taking ownership of their outcomes, and some were almost 30 years in the making.

“If we hadn’t been doing implantable cardioverter defibrillator (ICD) procedures the way we’ve done since 1985, that study probably would never have come out the way it did,” said John Day, MD, President Elect of the Heart Rhythm Society (HRS), electrophysiologist and director of Heart Rhythm Services at Intermountain Medical Center Heart Institute. Day referred to a study which found that threshold testing of ICDs during implantation may be safe, but not necessary. “We’ve learned so much and refined the technology so much. When these devices didn’t work, it sparked further research.”

This ongoing quest for refinement, improvement and knowledge — whether positive or negative — has medical innovation in general, and advances in cardiac electrophysiology in particular.

John Day, MD

John Day

Cardiology Today spoke with Day about his top four lessons learned from HRS 2014.

1. Sometimes a “necessary evil” renders itself no longer necessary.

According to Day, the findings from the aforementioned SIMPLE trial represent an important and potentially practice-changing lesson about the testing of ICDs during transplantation. In the study of 2,500 ICD patients, those randomly assigned to receive the device without threshold testing did not experience worse outcomes than those who underwent implantation with threshold testing.

“This one was a game-changer, because until about a month or two ago, electrophysiologists intentionally put the patient into a life-threatening rhythm,” Day said. “We intentionally put the patient into cardiac arrest, stand back, and make sure the device can resuscitate them. That’s the way we’ve done it since 1985.”

Day added that while in the vast majority of cases this testing did not lead to adverse events, there was always the possibility that the patient might not be successfully resuscitated. He noted that in addition to offering no benefits, threshold testing demonstrated a trend toward the need for CPR and the need for intubation.

“On the flip side of all this, testing the devices enabled us to refine the technology to the point that in 2014, results like this were possible,” he said. “So it was a necessary evolutionary process; a necessary evil. It allowed us to have these findings today.”

2. The best outcomes often occur when the patient meets the doctor halfway.

Also noteworthy, Day said, were findings from the ARREST-AF study, a follow-up on a previous study published in JAMA about lifestyle modifications and atrial fibrillation burden. In ARREST-AF, the researchers found that those who made aggressive lifestyle changes, such as weight loss, had a success rate of 87% at 42 months, compared with 48% among those who did not make any lifestyle changes.

“This has long been a complaint about AF ablations — why do we have so many repeat procedures? Why doesn’t it work for everyone?” Day said. “If you look at the numbers, AF is, in many ways, like coronary disease. It’s like a stent. A stent doesn’t fix plaque buildup or atherosclerosis; the disease is ongoing. The same is true of AF: If you don’t stop what’s driving the AF, it’s going to come back.”

Day said that these findings underscore the fact that patients must be active participants in their own care.

“It’s a two-way street,” he said. “The doctor needs to deliver the best possible procedure, but the patient also needs to change their life.

3. Leadless pacemakers are the future of device therapy.

Day said another very important presentation from HRS 2014 was the 1-year update on the Nanostim Leadless pacemaker (St. Jude Medical), which was part of the late-breaking clinical trial session.

According to the update, the device continued to perform well at 1 year. One implant failure occurred as a result of cardiac perforation during implantation, and perforations have also been reported in Europe since the device’s approval.

While these complications need to be investigated, Day said that the overall positive results with this device provide hope for a leadless future for cardiac devices.

“This really is the future of device therapy,” he said.  “As this technology improves, it will expand to more sophisticated pacemakers and implantable defibrillators.”

4. Blood thinning must be kept in range to minimize dementia risk.

Day and his colleagues, under the direction of T. Jared Bunch, MD, have focused a great deal of research on the connection between AF and dementia, particularly Alzheimer’s disease.

One study presented at HRS 2014 was specifically aimed at understanding the potential relationship between blood thinning treatments for AF and the risk for dementia.

“We found that by having either too much in the way of blood-thinning effects or too little can play a role in dementia risk,” Day said. “This is more for warfarin than for newer anticoagulants. Keeping warfarin in range seems to be very critical in minimizing dementia risk.”

He added that the possible effects of too much or too little blood thinning could involve microclots if there is not enough warfarin or microbleeds if patients are given too much warfarin, both of which can add to dementia risk over time.

“This is especially true in patients with coronary artery disease, who might already be on aspirin and Plavix. If these patients then develop AF and anticoagulation is started, now they may be on triple blood thinners,” he said. “These patients are particularly at risk of long-term dementia, and it may just be a result of these microbleeds over time.”