From Burden to Benefit: Does Screening for AF in HFpEF Improve Outcomes?

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Featured is the presentation entitled "From Burden to Benefit: Does Screening for AF in HFpEF Improve Outcomes?" by Carolyn S.P. Lam, MBBS, PhD, FRCP, FAMS, FESC, FACC, from Session 1 at the 2026 Western AF Symposium.

Thank you so much. Good morning, ladies and gentlemen. Thank you very much, especially to Dr. Nassir Marrouche, for organizing this and making sure that there is a “token” heart failure representation right here to talk about a heart failure topic. I'm going to address screening for AF in heart failure with preserved ejection fraction. 

This is the heart failure perspective of AF and AF ablation, and it's right here with Get With The Guidelines. This is what is being done in the U.S. If there is AF, two-thirds of patients will get amiodarone, maybe a few more than 1 in 10 will get cardioversion, and literally 1% will be considered for ablation.

I'm very grateful for these data from the TRIAD team and from Han Feng—thank you—that shows that even here at Tulane, with Nassir's group, AF ablation is received in less than 10% of patients with heart failure. So here's where we're starting off, even before we talk about screening for AF, we're talking about manifest AF in heart failure.

I'd like to show you what our heart failure guidelines say, and those boxes shown are from the ACC/AHA heart failure guidelines. When we see clinical AF, heart failure cardiologists will first think of the left side: stroke prevention, anticoagulate, because that's our class 1 recommendation—anticoagulate. From the heart failure outcome perspective, you'll see that AF ablation is only a class 2A recommendation. Despite accumulating data, you can see in the real world that very few patients get referred.

Let me examine some of the data that I think, from a heart failure perspective, is the most convincing for ablation. That would be, of course, the EAST-AFNET data. Because these were patients with heart failure, we started off with that population, and they were sent for early rhythm control therapy. Now, this is not an ablation trial. It's any rhythm control that could include drugs. I'd like to also point out that more than half the patients will have HFpEF, so that's great. And it did show a reduction in the primary composite endpoints that we care about, which is reducing heart failure hospitalizations, cardiovascular death, and stroke.

When we're talking about screening for AF, notice this is not talking about screening for AF—it's diagnosed AF. However, 30% of those cases were asymptomatic. So that does start to lend evidence to that. How do we treat asymptomatic atrial fibrillation in heart failure? 

What about AF ablation? What do we see as the totality of the data? Yes, it may be a bit more convincing in HFrEF, and those are the top studies that have been summarized in this meta-analysis. But the ones I've boxed out are the data for HFpEF. You can see when it comes to heart failure outcomes—so that's showing the heart failure events, not just hospitalizations, but also outpatient worsenings—you see that it crosses the line of benefit. So the data are not sealed and done from our point of view in HFpEF.

So here's where we are with clinical AF. And now let's go to burden: subclinical AF, detecting more than that. First of all, if you were to approach any heart failure cardiologist and talk about AF burden, please excuse us if we kind of say, "Oh, that's an interesting burden. Is it like heart failure burden?" So, it's not everyday speak in our world yet.

But if we were to look at it, these are emerging data. This is electronic health record opt-in database-type data. When they found close to 1000 patients with an insertable cardiac monitor and a history of heart failure, you'll see that there is a lot of atrial fibrillation: incidence almost half at 42 months, and new-onset atrial fibrillation was almost 25%.

What about if we look in a prospective study, because the prior was electronic health records? A prospective study, a beautiful study called LUX-DX Trends, was presented by Elaine Wan. Basically, in patients with a clinical diagnosis of HFpEF, the ICM detected new AF in more than one-quarter of patients at one year, and in more than 4 in 10 in about one and a half years.

So, this is a huge burden. What do we do about this?

As you know and have heard from the prior talk, there's a lot of debate about whether to anticoagulate or not. So, should we be treating subclinical AF like clinical AF? Here are the arguments that you see, and in heart failure, we really don't know what to do about subclinical AF and what burden and threshold should lead us to start treating. When is it worth it? When does it progress instead of regress? When does the risk of bleeding outweigh the risk or benefit of stroke prevention?

Do we have data about this? I think in a very obtuse way, we may from the LOOP trial. Now, the LOOP trial was actually not patients with heart failure, but individuals with stroke risk factors in which loop recording resulted in a much greater detection of atrial fibrillation. However, anticoagulation initiation did not significantly reduce the risk of stroke or systemic embolism in this group of patients.

However, the silver lining is that if you look at the subgroups and at the heart failure cohort, in patients who had an NT-proBNP above the median, which tended to be patients with heart failure or maybe those with undiagnosed heart failure, you see that in LOOP, there did appear to be a benefit with screening and anticoagulating if there was screen-detected AF in patients with a high NT-proBNP, so that may be hopeful.

So, here's the summary of what I've said so far. You can see, when it comes to subclinical or device-detected AF, we're really threading very thin in heart failure. From the stroke prevention perspective, there's the subgroup analysis from LOOP that provides intriguing insights. From the heart failure outcomes perspective, I still think EAST-AFNET and that asymptomatic one-third of that population may carry hope.

We obviously need new data. I am very proud and pleased to tell you about the CASTLE-HFpEF trial, led by Dr. Nassir Marrouche. I'm very grateful to be the heart failure counterpart there. It's a trial that will answer 2 things: first, should we screen patients with HFpEF for AF? And second, should we then ablate them if we find it?

This is the overall scheme, taking patients with bona fide, if I may, HFpEF, inserting an implantable cardiac monitor, and then randomizing those either with overt AF or with screening-detected AF to catheter ablation or usual care and following them up for proper outcomes. So we're very excited about that. All kudos to the TRIAD team for this trial. And we're very hopeful that many of you will help us and support us in this trial.

Thank you.