Expert in the Room: Treatment of Atrial Fibrillation
Harriett Bennett: Hello and welcome to “Expert in the Room,” an audio podcast from the Agency for Healthcare Research and Quality, or AHRQ. I'm Harriett Bennett. A recent report published by AHRQ compares treatment strategies for atrial fibrillation. Atrial fibrillation, or A-Fib, is a condition that affects more than two million Americans. We sat down with Dr. Sana Al-Khatib, a cardiologist and cardiac electro-physiologist at Duke University Medical Center to discuss this comparative-effectiveness research report and better understand how these findings can benefit practicing clinicians. Thank you for joining us, Dr. Al-Khatib.
Dr. Al-Khatib: Thank you Harriett. It's my pleasure to be here.
Harriett Bennett: So Dr. Al-Khatib, how common is A-Fib in the United States?
Dr. Al-Khatib: Atrial fibrillation is a very common rhythm that we see in clinical practice. In fact, it is the most common arrhythmia that we see and treat. And as you pointed out, more than two million Americans have atrial fibrillation today. If you look at patients who are in their 80's, about 8 percent of those patients have atrial fibrillation because the incidence increases with age.
Harriett Bennett: So what is the impact of A-Fib?
Dr. Al-Khatib: In terms of how atrial fibrillation can affect patients, it is certainly associated with bad outcomes. Atrial fibrillation can lead to congestive heart failure in people who have weakened hearts. It can cause decompensated heart failure. But in people who have normal hearts, if the rate is not well controlled it can lead to tachycardia-induced cardiomyopathy, and so that's when the heart muscle weakens because the heart rates stays fast most of the time. And certainly atrial fibrillation can cause heart attack in people who have coronary artery heart disease. And the most dreaded complication from atrial fibrillation is a stroke, because people with atrial fibrillation may form clots in their left atrium. So that's really concerning. Lastly, atrial fibrillation can also impact a patient’s quality of life, in some patients the symptoms can be debilitating.
Harriett Bennett: Dr. Al-Khatib, how is A-Fib treated?
Dr. Al-Khatib: So when we see a patient in our practice with atrial fibrillation, there are three things that we have to address. The first thing is the risk of having a stroke and then we really need to assess that risk and decide on the best treatment to minimize that risk of having a stroke. So that needs to be done in all patients. The second thing that we need to address is the rate control, making sure that when the patient is indeed in atrial fibrillation that their heart rate is not too fast. So we are shooting for a heart rate that is less than 100 beats per minute. As I mentioned earlier, if the rate is not well controlled, that can lead to cardiomyopathy.
So it's a major issue, and the fast heart rate can also affect the patient’s quality of life and cause symptoms. That's why this is something that we need to address with every patient. And then of course the third thing, especially if patients continue to have symptoms despite good rate control, then we talk about rhythm control. What we mean by rhythm control is the ability to restore normal rhythm in those patients and maintain them in normal rhythm.
Harriett Bennett: Are there any gaps in the knowledge about A-Fib protocol? In other words, why is it even important to conduct a comparative effectiveness study on this issue?
Dr. Al-Khatib: Knowing the best strategy or the best modality to achieve rate control, to achieve rhythm control, there are several uncertainties regarding how to best achieve rate control and how to best achieve rhythm control. Especially in different subgroups of patients. And that's what prompted us to do the systematic review that we're talking about today.
Harriett Bennett: What were some of the key questions that AHRQ tried to answer with this particular study?
Dr. Al-Khatib: So as I mentioned earlier, when it comes to the management of atrial fibrillation, we have to address stroke prevention, rate control, and rhythm control. In this particular review, we did not tackle stroke prevention. There is another review that was done also by AHRQ related to stroke prevention. So our systematic review was focused on rate control and rhythm control. Now in relation to rate control, we had three main questions.
The first question was: What are the comparative safety and effectiveness of pharmacological agents used for ventricular rate control in patients with atrial fibrillation, and do the comparative effectiveness and safety differ among different subgroups of patients? Our second question had to do with the comparative safety and effectiveness of strict rate control versus more lenient rate control in patients with atrial fibrillation and again we were interested in looking for variations across different subgroups of interest. And then the third question related to rate control had to do with the comparative safety and effectiveness of newer procedures and, you know, other non-pharmacological rate control interventions seeing if we can find any differences across different subgroups of patients.
Harriett Bennett: And you mentioned rhythm control. What were the key questions there?
Dr. Al-Khatib: So we actually had two main questions related to rhythm control. The first question had to do with the comparative safety and effectiveness of available antiarrhythmic medications and electrical cardio version for restoration of normal rhythm. So that's really converting patients from atrial fibrillation to sinus rhythm, and again, we were interested in looking at those in different subgroups of interests.
And then our second question in relation to rhythm control had to do with the comparative safety and effectiveness of newer procedural rhythm control interventions like catheter ablation and pharmacological agents for maintaining sinus rhythm in patients with atrial fibrillation. Our last question had to do with comparing rate and rhythm control. And so really our question was: What are the comparative safety and effectiveness of rate control therapies versus rhythm control therapies in patients with atrial fibrillation and do those findings differ across different subgroups?
Harriett Bennett: And what did you find in all of this, Dr. Al-Khatib?
Dr. Al-Khatib: When it comes to rate control, we found that there is definitely benefit in terms of controlling the rate in patients with atrial fibrillation. Unfortunately, we were not able to advise people as to which medication is better than other medications at controlling the heart rate. When it comes to procedures to achieve rate control, we found that procedures were generally superior to medications at controlling the heart rate. So those were the main findings in relation to rate control.
Harriett Bennett: What were your findings for rhythm control?
Dr. Al-Khatib: So in relation to rhythm control, as I mentioned, we really focus first on restoring sinus rhythm. And there really the main finding was for comparisons of methods for electrical cardio version for conversion to sinus rhythm. There was a high strength of evidence that use of a single biphasic waveform is more effective at restoring sinus rhythm than using a single monophasic waveform. When we looked at different antiarrhythmic medication, we couldn't find any strong data in support of one antiarrhythmic medication versus others. But we found a high strength of evidence supporting catheter ablation, also known as pulmonary vein isolation, versus antiarrhythmic drugs for maintaining sinus rhythm in a select subset of patients and those are mostly patients who are younger and who have the type of atrial fibrillation, which is paroxysmal, meaning they go in and out of atrial fibrillation.
Harriett Bennett: What about the studies comparing rate control to rhythm control?
Dr. Al-Khatib: So we actually found multiple studies that compared rate control strategies with rhythm control strategies; mostly rhythm control strategies using antiarrhythmic medications. And we actually found, at least in those studies, that the two strategies were comparable in terms of their effect on all-cause mortality, cardiovascular mortality, and stroke. I do need to point out that those studies mostly included patients who are older and are less symptomatic from their atrial fibrillation. So the findings of those studies may not generalize to younger patients who are more symptomatic.
The other thing that I would point out is that we were able to find that rate control strategies are superior to rhythm control strategies in reducing hospitalizations from cardiovascular events. Because of the wide range of options within each strategic treatment approach for atrial fibrillation, we concluded that additional studies are needed to evaluate the comparative safety and effectiveness of individual antiarrhythmic medications and procedures especially within subgroups of patients that are of great interest to us, like patients with structural heart disease, patients with heart failure, older patients, so on, so forth.
Harriett Bennett: Dr. Al-Khatib, with respect to race, ethnicity, and gender, were there any report findings that talked about those differences or were they mostly related to age and type of heart disease?
Dr. Al-Khatib: Harriett, you ask an important question. We certainly looked at that. Unfortunately, the vast majority of studies that we found did not report their findings based on these different subgroups.
Harriett Bennett: Dr. Al-Khatib, let me thank you again for this important information and for your time and expertise.
Dr. Al-Khatib: You're very welcome. It's my pleasure.
Harriett Bennett: All of this information is found in the final report, Treatment for Atrial Fibrillation. To review this and other reports from AHRQ's Effective Health Care Program, please go to www.effectivehealthcare.ahrq.gov. On behalf of AHRQ, thank you for joining us. This has been a production of the U.S. Department of Health and Human Services.