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Panel discusses prevalence of AF, effect on quality of life
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Atrial fibrillation is becoming more prevalent among patients and continues to present as a complex arrhythmia disorder.
Carl J. Pepine, MD, chief medical editor of Cardiology Today, moderated a round table discussion that included Peter Kowey, MD; Bernard Gersh, MB, ChB, DPhil; Albert L. Waldo, MD; Andrew Epstein, MD; and Douglas P. Zipes, MD, during the American Heart Association’s Scientific Sessions in November in New Orleans. The panel discussed the prevalence, research, treatment strategies and new drug development in AF.
In part one of this two-part round table, the group considered the increasing prevelance of AF, how it affects quality of life and the lessons learned from the AFFIRM trial. Part two will appear in next month’s issue of Cardiology Today.
Carl J. Pepine, MD: Why do you think atrial fibrillation has become more frequent among patients?
Bernard Gersh, MB, ChB, DPhil: AF is one of the epidemics of CVD in the 21st century. In terms of epidemiology, there has been a significant increase in incidence and prevalence over the last 20 years. The Kaiser Permanente study estimated that by the year 2015, there could be about 6 million people with AF.
Albert L. Waldo, MD: Patients with HF and coronary artery disease are living longer. It’s a perfect storm, so to speak.
Peter Kowey, MD: We’re also looking for it more. We’re much more active in ECG monitoring patients. Some of this increased monitoring is incidental as it is in our pacemaker populations.
Andrew Epstein, MD: When elderly people have strokes in the setting of AF, the consequences are much higher than if AF is absent. There is doubling of patients confined to a bed-ridden state. AF may be a cause for strokes which have no other explanation and therefore such patients now undergo ECG monitoring.
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Douglas P. Zipes, MD: Right now we crudely lump AF into paroxysmal, persistent and permanent, and that’s extremely gross at an electrophysiologic level because they are probably quite different diseases influenced by comorbidities, duration and other factors.
Pepine: Is there any difference in outcome among those three categories?
Gersh: Whether AF is paroxysmal or persistent probably does not influence the risk of stroke, but I tend to think of AF as two different diseases, as diseased atrial substrate on one hand and a trigger on the other.
Zipes: These are areas that we’re still learning. For example, we talk about paroxysmal AF having the same stroke incidence or prevalence as permanent or persistent AF, and we don’t really know what that means. What is paroxysmal and how long does it have to last to be classified as a stroke risk?
Pepine: I’d like to hear some thoughts relative to the quality of life issues that impair the patient with AF.
Waldo: The issue is, if you have AF, does it make a difference if you are rate or rhythm controlled?
In the AFFIRM trial, it didn’t make a difference. On the other hand, SAFE-T provided the best data that demonstrated there was a difference in quality of life.
Pepine: So you’re an advocate that heart rate control is important to assure better quality of life or is not important?
Waldo: Once you get AF group data from most studies, including both the AFFIRM and RACE trials, it shows you’re no better off in sinus rhythm than you are in rate control. The only trial I know of that showed quality of life was better in sinus rhythm was SAFE-T.
Gersh: As is the case with many trials, the patient population is highly selected and entry bias is a fact of ‘trial life.’ I agree with you completely about AFFIRM, which did not show a difference in quality of life. But to get into AFFIRM, you had to tolerate your AF sufficiently well that you could be randomized to rate vs. rhythm control.
Waldo: In order to get into AFFIRM, you had to warrant therapy. You had to be able to take at least two antiarrhythmic drugs and warfarin.
Gersh: I would emphasize that patients who entered AFFIRM were to some extent selected because they were unable to tolerate their symptoms. Individuals who were highly symptomatic due to diastolic dysfunction, severe LV hypertrophy, congestive HF, etc., were underrepresented in AFFIRM as is the case in most trials. But in general, I agree that you can extrapolate AFFIRM data to a wider population.
Epstein: When AFFIRM was enrolling, it was not known whether a heart rate control or a rhythm control strategy was superior. You’re right; the highly symptomatic people were excluded.
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Waldo: They were not excluded if they were symptomatic on presentation because they had not been adequately rate-controlled.
Kowey: Highly symptomatic patients were excluded from AFFIRM in our center. But to be fair, rate control is fine for many patients if it is done correctly.
Waldo: Our experience with AFFIRM was that the biggest problem with patients presenting with symptomatic AF was rate control, and, unfortunately, many patients don’t achieve good rate control.
Zipes: Heart rate is a critical issue and a number of patients probably have a tachycardia-induced cardiomyopathy at rates of 85 bpm or 90 bpm. How many of us really spend careful time to control the ventricular rate in our patients with AF? They come in, they get an ECG, or you examine them and that’s your ice-pick view of what their rate is.
Waldo: The AFFIRM trial provided guidelines to monitor and achieve adequate rate control, like the six-minute walk test, and did this well. It is what I use all the time now and it makes a big difference.
Gersh: We don’t know that it makes a big difference because this is the whole reason why the RACE II trial is being done. We believe optimal rate control makes a difference and is certainly logical. But proof is lacking.
Zipes: Suppose the follow-up [of AFFIRM] was 10 years, what would have happened to those who had AF with ventricular rates that were just 10 beats higher than those with similar rates among patients in sinus rhythm? I’ll bet you this would have had significant effect on outcome.
Kowey: The other thing about quality of life is the inadequate instruments we use to assess it. If you apply the right instruments, quality of life scores among patients in AF are worse than among patients with HF.
Blame over-extrapolation of the AFFIRM results for this. We sometimes take this arrhythmia much too lightly, and we subject people to needless suffering.
Zipes: AFFIRM gave us the excuse.
Kowey: Exactly. Rate control is cheaper, easier and faster. If you go to a cardiologist, they’re going to try to get you back into sinus rhythm. If you go to a primary care doctor, you’re going to get an attempt at rate control.
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Gersh: How well are patients rate-controlled? How many people do what we do to assess adequacy of rate control? [We] either obtain a Holter or a treadmill or occasionally even both.
Waldo: With regard to rate control, the difference between AFFIRM and RACE was that the RACE trial found that all you have to have is a rate below 100 bpm. That’s less than 120 bpm. I’m not advocating rate control per se, but we have to really respect the data. When you look at the RACE trial, the mean rate was 84 bpm and the mean ventricular rate in AFFIRM it was 78 bpm. What’s the difference? Probably not meaningful.
Zipes: Six bpm not meaningful? If you do the math, that comes out to be more than 3 million extra heart beats a year.
Waldo: We’re going to find out from RACE II. Don’t misread me; I don’t think that rhythm control is worthless.
Pepine: Another observation that I noted is that the general physician, even for new-onset AF, has forgotten about cardioversion. For patients that we all cardioverted in the ER, before we knew that we should do TEEs, the general physician says ‘take warfarin and a beta-blocker and I’ll see you in the office next week.’
Waldo: I know you’re right, but the culprits in my judgment are the American College of Physicians and the American Society of Internal Medicine who published guidelines that said rate control is preferable. AFFIRM never said that. Most cardiologists, certainly electrophysiologists, dispute that.
Gersh: These are people seeing 20 to 30 patients a day. For me, the easiest thing to do is call the cardioversion unit, send the patient and have them come back to me. If they’re going to be on anticoagulation, they’ve been bridged and it’s easy for me. It’s not that easy for a doctor in a busy office when you’ve got patients, and you need to refer to a cardiologist. I have some sympathy, or sensitivity.
Part two of this round table will appear in next month’s issue.