Episode Transcript
Interviewer: A procedure called catheter ablation lowers the risk for complications and death in patients with atrial fibrillation.
Announcer: Examining the latest research and telling you about the latest breakthroughs. The Science and Research Show is on The Scope.
Interviewer: Today I'm talking with Dr. Nassir Marrouche from University of Utah Health about catheter ablation for treating atrial fibrillation in patients with heart failure.
AFib and Heart Failure
Dr. Marrouche: You know, more than 20 million people in America suffer from heart failure, and a significant amount of these people have an ejection fraction or weak heart muscle, less than 35 percent. That's defined as weak heart muscle. And these guys are high risk of sudden cardiac death. We know this for years now, and that's why they need to protect it.
Now, more than 30 percent of the heart failure patients are suffering or will suffer from atrial fibrillation. It's a big number. Very enormous. So this is becoming a big dilemma, how to treat these patients, and we know that in this patient population, the atrial fibrillation itself increases the risk of dying, increases the risk of stroke and so on. And over the years, there's multiple studies have been done using different kind of drugs to improve outcome in these patients.
In fact, our papers published in the New England Journal show there's no difference if you use any kind of drugs or use nothing. The mortality will stay the same. Stroke risk will stay the same. Hospitalization rate will stay the same.
Atrial Fibrillation Catheter Ablation
Interviewer: Catheter ablation is a completely different approach. Can you explain what that is?
Dr. Marrouche: Me, personally, and our team has started working on this before we came to the University of Utah, around 1999, 2000, which is, simplified, is the catheter-based procedure, as the name says, to target specific cells within our heart, specifically in the atrial, the upper chamber of the heart, to cauterize or kill, trigger the tissue causing irregular heartbeat. There's different ways to do this, and over the last 20 years we learned a lot how to do that and what's the best way to do it, but still there is still at least 5 to 6 strategies of ablating atrial fibrillation.
Catheter Ablation Procedure
Interviewer: And all of this is done within a few hours and the patient walks away, or ...
Dr. Marrouche: If I would have given you this interview in 2000, when we were in the Cleveland Clinic, I would have told you 11 hours procedure to 10, nine. We went up to six, we were excited. It's a two-hour procedure today. I mean, the ablation itself, the delivering energy and heating tissue, is probably 45 to 90 minutes maximum.
Interviewer: So even though this procedure has actually been done, like you said, for about 20 years I think you said?
Dr. Marrouche: Mm-hmm.
Interviewer: It sounds like really what wasn't known is how effective it was, especially compared to drug treatments.
Dr. Marrouche: The unknown, until we just presented the recent study was, does a-fib ablation, per se, improve primary endpoints of mortality or worsening heart failure hospitalization in a group of patients suffering from heart failure? Now, that's that we focus on, because we wanted to look at sick patients who suffer from this disease to look at.
Interviewer: I see.
Dr. Marrouche: Not quick, but to look at . . . they have higher events. These patients die, about 30 percent, 40 percent of them die because of the heart failure and diseased hearts. So we wanted to look at this population, see can we save life in this high-risk population? And that wasn't done until recently.
Catheter Ablation Outcomes
Interviewer: In a nutshell, what were those results?
Dr. Marrouche: Catheter ablation showed a significant reduction in all cause mortality when compared to conventional guidelines based standard treatment, standard of care treatment. Catheter ablation, when you looked at the mortality and heart failure combined as a composite endpoint, showed a significant reduction of the composite point of the two together. When you looked at the hospitalization only, catheter ablation was superior to drugs or standard of care treatment in lowering hospitalization for heart failure.
Catheter ablation was also, which is very important for the listeners as well to know, in lowering the risk of cardiovascular mortality. Not all cause mortality only but also cardiovascular mortality.
Interviewer: Okay, specifically, yeah.
Dr. Marrouche: Sudden cardiac death and failing pump and so on. So that improved the outcome. And actually the relative risk reduction in cardiovascular mortality was 51 percent. That means that every other patient will recover. And what's important for causal AF, if you look at the data and hopefully the paper will be out soon and you read it, we need only to treat eight patients to save . . .
Interviewer: Eight?
Dr. Marrouche: Eight patients to save one life. That's a big deal for a study like this.
Interviewer: One thing you alluded to earlier is that, I mean, these patients are already pretty sick, right? And so it seems pretty impactful that you can make a change even at this stage.
Dr. Marrouche: You have the data from causal. The earlier we treat this patient in this progress, in the stage of heart failure, the better the outcome. So if you treat them when they start getting to heart failure and the pump is 30 percent and 35 percent, 29 percent in function and ejection fraction, they do way better when they are at the end stage of the disease, when they're almost dying. So that's important as well, go and seek treatment as early as possible, and ablation should be the best option for this population.
Heart Failure and Atrial Fibrillation Research
Interviewer: And so what's next in this line of research?
Dr. Marrouche: As much as I'm excited about catheter ablation and promoting it worldwide now because of the solution of our patient, but I'm telling my colleagues and partners, be careful and don't explode and start giving it to everybody randomly. We need to be thinking about selecting this patient and the MRI imaging, the finding fibrotic tissue and the extension of the disease in our atrial and our ventricles will better help redefine this patient. That's the next big study we're putting together now is randomize this patient based on the amount of scarring in their heart, to ablation procedures or not, and see what the primary or how the primary endpoint looks like, mortality, hospitalization, and strokes.
Announcer: Interesting, informative, and all in the name of better health. This is The Scope Health Sciences Radio.