Resources

  1. Marrouche  NF et al. Catheter Ablation for Atrial Fibrillation with Heart Failure. N Engl J Med 2018;378:417

Transcript

Dr. Frank Domino:
Harold is a retired postal worker with a history of myocardial infarctions. He's had AFib for the last three years. He's on thromboprophylaxis with apixaban 5 mg twice a day. He was recently hospitalized for an episode of heart failure. And echo then showed some cardiac enlargement and a reduced ejection fraction down to 32%. While he was in the hospital, his cardiologist mentioned a procedure that might help stop his atrial fibrillation. But the patient really didn't understand what he's talking about, so he came to you to get advice.

Hi, this is Frank Domino, Professor in Family Medicine and Community Health at the University of Massachusetts Medical School. And joining me to discuss atrial fibrillation and heart failure today is Dr. Alan Ehrlich. Dr. Ehrlich is Clinical Associate Professor at the University of Massachusetts Medical School in the Department of Family Medicine and Community Health, and he's also the Executive Editor at DynaMed. Welcome to the show, Alan.

Dr. Alan Ehrlich:
Hi Frank. Thanks for having me on.

Dr. Domino:
Wow. So this is a fairly complicated patient. He's got heart failure. He's got AFib. He's on quite a few different medications. Just remind us a bit about atrial fibrillation. In the past, we had a variety of approaches. Which is better? Is it better to control his rate or better to control his rhythm?

Dr. Ehrlich:
So in general, for patients with chronic atrial fibrillation, the first line of therapy is rate control. The rhythm control, trying to restore them to normal sinus rhythm, often is associated with less time atrial fibrillation but worst outcomes, particularly with some of the medications, which although they can control atrial fibrillation, can put you at risk for other types of arrhythmias. And so the idea of rhythm control, keeping people at normal sinus rhythm, is really reserved for patients who remain symptomatic, despite rate control, or perhaps it's new onset, and there might be some reversible cause such as hyperthyroidism, that if you correct then by restoring them to normal sinus rhythm, you would expect them to largely remain there.

That being said, we know that patients who have heart failure, who have atrial fibrillation, often have their heart failure exacerbated because the atrial fibrillation prevents them from having the preload or what we call the atrial kick. And so they may be more symptomatic. And so that's another group for which various attempts to maintain sinus rhythm have been tried in the past.

Dr. Domino:
It is interesting about how when we try to control something like the rhythm and we think we're gonna be causing a benefit, we've actually caused some harm in the past. Well, you bring to our attention a new trial, the CASTLE-AF trial for patients... Involving patients with heart failure and atrial fibrillation. Can you talk a little bit about that, please?

Dr. Ehrlich:
Yes. So this is a very exciting new trial. The reason they did the trial in the first place was because they have shown some symptomatic benefit for patients with heart failure who have atrial fibrillation by trying to restore sinus rhythm. But there haven't been any benefits for heart outcomes. There's been some suggestions, but nothing definite. So in this trial, they randomized a little over 360 patients. And in order to get into the trial, first you have to have heart failure class II, III, or IV on the New York Heart Association Classification. So these are people who have some degree of symptomatology.

Secondly, you have to have atrial fibrillation. It didn't have to be chronic. It could be either paroxysmal or chronic atrial fibrillation. And because of the way they're doing the trial, in addition to the heart failure that these patients had, all these patients had to have an implanted cardiac defibrillator, or a cardiac resynchronization therapy device in place, or agree to have one put in.

These are also people who either failed medical therapy at restoring regular rhythm, or were intolerant, or who just refused.

Dr. Domino:
So these are quite ill and also very aggressively treated folks?

Dr. Ehrlich:
Exactly. So they follow them for about three years, have got randomized to catheter ablation, have got randomized to optimal medical therapy, which included trying to keep them in sinus rhythm. And what they found was that there was a significant benefit seen in the ablation group. For death from all causes, it was 13% in the ablation group versus 25% in the medical management group, and that 12 percentage point different is a number they needed to treat of about nine.

Dr. Domino:
That's amazing. So wow.

Dr. Ehrlich:
Most of that came from reduced cardiovascular death, which went from... That also was reduced by about 10 percentage points.

Dr. Domino:
So the cardiac ablation therapy in these high risk patients seem to have an improved outcome on mortality. That's wonderful. But ablations involve... Are fairly aggressive. Were there any complications to this intervention?

Dr. Ehrlich: 
So in general, the ablation is gonna be well tolerated. There are some pericardial effusions, three patients reported, and three patients had some bleeding problems. But in general, it's considered a pretty safe procedure and the complications are going to be relatively mild. What was interesting is, in terms of figuring out why did they have all this benefit, the patients did not get converted to normal sinus rhythm all the time. What they did was, they were spending a lot more of their time in normal sinus rhythm. So about 60% of the time was in normal sinus rhythm, compared to the medically managed group, which was more about 20% of the time.

Dr. Domino:
So they ended up staying on thromboembolic prophylaxis throughout the study.

Dr. Ehrlich:
Yes.

Dr. Domino:

Very good. Well, Alan, what are we gonna tell Harold here? So Harold is coming in. He's already quite ill. He's already been on quite a few different medications. I'm sure he's worried and he realizes that he's symptomatic from his heart failure. Should we encourage him to consider this?

Dr. Ehrlich:
So I think this is a practice-changing type study. I think he should consider it, with understanding a few things. First of all, this is only for patients who have both heart failure and atrial fibrillation. For regular atrial fibrillation patients, you would only do it if they were symptomatic despite rate control. And if they have heart failure but it's not severe enough, under 35%, it's not clear that there's benefit for that group. So that's the first thing. The second thing is that it's not going to cure his atrial fibrillation. It may improve how often he is in normal sinus rhythm, but it may not be 100% of the time.

Dr. Domino:

I think that's a really important point because patients have expectations that things that we do, whether it's a pill or a surgery, is going to always cure problems. And we should appropriately engage his expectations that this will hopefully make him feel better, hopefully make him live longer, but it won't necessarily resolve the ills that he currently has.

Dr. Ehrlich:

And he's likely to still need the thromboembolic prophylaxis.

Dr. Domino:
Yeah. Alan, this is great. I think we're gonna see this in our patients more and more. We'll see a little bit more aggressive care from our friends in cardiology. And hopefully, our patients will benefit by both feeling better and living longer. Thanks for bringing this to our attention, Alan.

Dr. Ehrlich:

Thanks, Frank.

Dr. Domino:
Practice pointer. For your patients with heart failure and atrial fibrillation, be aware that they may be getting treated with a cardiac ablation. None of their medications may need to be changed, but this may become a much more common and beneficial procedure. Join us next time when we discuss the new CDC guidelines concerning vaccines in adults.