The Management of Atrial Fibrilliation and the Value of Sinus Rhythm
EXPERT INTERVIEW With Eric Prystowsky, MD
Medscape recently had the opportunity to discuss the management of atrial fibrillation (AF) and
the value of sinus rhythm with Eric Prystowsky, MD — Consulting Professor of Medicine, Duke University
Medical Center, Durham, NC and Director of the Electrophysiology Laboratory, St. Vincent's Hospital,
Indianapolis, IN.
Question: What factors affect the overall management strategy for
atrial fibrillation?
Dr Prystowsky: I approach this from several viewpoints. As
one of the writers of the first international guidelines for the management of patients with AF and
also the updated guidelines, and sprinkling into this the personal experience of several decades
of managing patients with AF, it is important to have a game plan about the present and future management
of that individual.
For example, is this paroxysmal or persistent AF? Are there concomitant medical illnesses that
may affect your long-term and even short-term game plan? Is this postop management of atrial fibrillation
versus somebody who has been in AF for years? These issues affect whether you're going to do rate
or rhythm control, drugs, ablation and so forth.
The next set of issues relate to rate control, rhythm control and the risk of stroke.
The first thing you have to make sure about right away is the risk of stroke and need for risk
reduction.
Then, you have to be sure you can control their heart rate. Regardless if you select a rate
or rhythm treatment strategy, you have to at least be sure that when they do have episodes of AF
that they are not going so fast as to get themselves into trouble.
The third thing is the rate versus rhythm question. Is this a person who will do better in sinus
rhythm or is this a person who will do very well just staying in good rate control?
Once you've considered the issues and answered all those questions, you can then lay out a reasonable
treatment goal for that individual.
Question: What are the short- and long-term goals you set for your
patients?
Dr Prystowsky: The short-term goal is to ensure you've covered stroke
risk, whether or not sinus rhythm is your long-term goal. Managing stroke risk to cover the period
of time around the cardioversion is important, because patients who have been in persistent AF for
48 hours or more develop atrial myopathy. They're known to be at risk for developing thrombi that
can embolize and cause strokes and other problems, and require three weeks of stroke risk management
before and at least four weeks after cardioversion.
Short-term, you must be sure that you also take care of rate control. By short-term, I mean
during the first few days of treatment to be sure that the patient will not develop a tachycardia-mediated
cardiomyopathy.
Long-term goals are very different. If my long-term goal for a patient is to maintain sinus
rhythm, then I know I am going to try to cardiovert the patient. My immediate concern is risk of
stroke, but I don't want to postpone cardioversion for too long since it may be more difficult to
achieve sinus rhythm.
On the other hand, if it's a 75-year-old with newly discovered AF who is truly totally asymptomatic
and you feel he or she is an excellent candidate for rate control, once you've covered the stroke
risk, you need to be sure this patient has a long-term goal of good, adequate rate control.
The short-term goal is to stabilize the patient, make sure he or she is not in a risk situation,
and then you can determine where the fork in the road is, that is rhythm or rate control long-term.
Question: Which patients are best suited for a rhythm control strategy?
Dr Prystowsky: It is clear that some people can do well with either a rate
or rhythm control strategy. There have been a series of randomized, prospective trials published
in the last few years that have addressed this issue. The one that is most often quoted—and
clearly the biggest trial—was the AFFIRM study.
The AFFIRM study asked the question, "Do people have a better or worse chance or no difference
in survival if they have rate control versus rhythm control?" Patients did equally well whether they
were rate or rhythm controlled. That conclusion has been misrepresented, or at the very least misunderstood
as physicians have extended the trial results to other groups of patients.
The entry point in this trial was patients who were suitable for either rhythm or rate control
and who were at high risk for events such as stroke. It turned out to be a patient population averaging
about 70 years old.
The issue is, can you apply the AFFIRM data to a 30-year-old, a 40-year-old and a 50-year-old?
I say you certainly cannot.
That kind of data migration, or conclusion migration, is really not appropriate. You have to
stick to the question asked and the population in whom it was asked.
The other major issue is that there was a substantial number of patients who were potential
candidates but not enrolled because either the treating physician or the trialist did not think they
were adequate candidates for rate control. In other words, they needed sinus rhythm, or they weren't
going to tolerate just being out of sinus rhythm.
That's a large group of excluded patients even in the elderly patient population. In an AFFIRM
type of patient population, I think they have clearly shown rate and rhythm are equivalent treatment
strategies, as long as rate control gets the patient to a point of feeling good.
There are three types of patients that I would initially target for sinus rhythm.
In patients who have not been studied, my own bias is that sinus rhythm is best, until someone
shows me that rate control in a person in the younger age group is better. Until we know more, I
think that sinus rhythm is the preferred initial approach.
Sinus rhythm is also clearly the approach for a second group of patients, in whom you've tried
rate control and there are still substantial symptoms. You get them back into sinus rhythm and suddenly
they feel much better.
The third group of patients are individuals in whom AF, if not now, but in the future, could
be a problem for them. These typically are people who have diastolic compliance problems in their
left ventricle.
If a person has ventricular hypertrophy and is on the borderline of diastolic dysfunction or
has, even mild to moderate dysfunction that's going to worsen over time, I think leaving them in AF
may be an unwise thing to do. At a point in time when there is a problem, it may be too late to restore
sinus rhythm.
Question: Do you believe that being in sinus rhythm has an impact
on disease progression?
Dr Prystowsky: First of all, let's look at the heart itself.
Will keeping somebody in sinus rhythm make a difference as to whether or not that person's heart
stays the same? It's well known if you stay in AF, you will have progressive changes in the atrial
tissue that can become permanent. These changes are both anatomic, for example atrial dilatation,
as well as electrophysiologic, such as shortening of action potentials in the atrium, and can promote
the continuation of AF and make it difficult, even several years later, to maintain and restore sinus
rhythm. Persistence of AF can change the atria.
The next question is, "Will that change affect the cardiovascular state of that person?" That
question is difficult to predict. In some patients who have heart failure, it's been shown even with
good rate control they just simply don't do as well because of the AF. When you restore sinus rhythm,
they literally feel better and do better.
The same holds true for people who have substantial left ventricular diastolic compliance problems.
Again, will they actually get worse if you leave them in AF? I don't think we have data to support
that.
I think there are people in whom maintaining sinus rhythm will prevent further deterioration
of left ventricular function, and I believe there are some data to suggest that's true. I don't think
there are any data to suggest that's true for hypertrophy.
Question: Do you think AF is an under-recognized cardiovascular risk
factor?
Dr Prystowsky: Atrial fibrillation, I believe, is felt
by many people to be more of a nuisance than a real problem.
There are a number of patients with AF who will call you for even four seconds of AF. Their
chart is on your desk the next morning: Mrs. Smith had a brief run of AF yesterday.
No matter what you do, you're never going to make that person happy, so doctors don't necessarily
want to deal with AF. They don't want to find out if a patient has it. They'd rather it just simply
go away.
AF can cause strokes. It can cause heart failure. It can cause deterioration in health. In study
after study it's been associated with increased mortality. It is a problem, regardless of being a
nuisance.
I think it is totally unrecognized in a large part of the medical community how serious AF can
be. What makes it worse is that AF can disguise itself because it is frequently asymptomatic. A patient
has a stroke or a TIA, and his or her doctor doesn't do the appropriate workup, which is long-term
monitoring to see if, indeed, the person in that age group might have unrecognized AF, and if so
needs to be aggressively managed to prevent future strokes. This goes on all the
time.
It's a nuisance and therefore avoided, but it's also grossly unrecognized because of its very
frequent asymptomatic presentation.
Atrial fibrillation has a very important effect on the health of our citizens. If you look at
the major expenditure for hospitalizations in arrhythmias, it's usually AF. People get admitted to
the hospital when it can be totally outpatient managed.
Our job to educate on AF is dramatically important, not only for the individual health of the
patient, but for the health of the entire medical healthcare system.
Question: Please just comment on the public health challenge of atrial
fibrillation.
Dr Prystowsky: From a global perspective there is a need
to identify the causes of AF and find ways to minimize its occurrence.
Let's look at risk factors. Probably the most important risk factor, certainly in western civilization,
is hypertension. Hypertension is associated with at least 40%-50% of the patients who have AF. Patients
with hypertension tend to get left ventricular diastolic dysfunction, which often translates to increased
pressure in the left atrium.
Data published in the
Journal of Cardiovascular Electrophysiology have shown pulmonary
veins are largest in a subgroup of patients who have both hypertension and AF versus hypertension
alone, and versus patients without hypertension.
Most patients with AF have their triggers in the pulmonary veins, and one could hypothesize
that there are stretch receptors that cause increased automaticity that are more actively engaged
in patients who have significant hypertension, pressure changes, and so forth.
Also general cardiovascular care, such as minimizing heart failure and coronary disease, will
again minimize the risk of AF. Conditions such as sleep apnea can increase the risk of AF. Attention
to patients with these problems will minimize the occurrence of AF.
We're never going to totally eradicate it based on just those risk factors, but we could hopefully
have a substantial reduction in the numbers of AF patients.
The second thing is how can we best manage AF in a cost effective way. First of all, most people
with AF do not have to be hospitalized. Clearly, there are exceptions, such as for patients starting
drugs that might be somewhat risky for proarrhythmia, which you feel more comfortable starting in
a hospital under observation.
There are some people whose AF has caused worsening of heart failure. But for the most part,
AF does not require a person to be hospitalized, including cardioversion. In most people, you can
perform cardioverversion as an outpatient and send the patient home the same day. An exception is
a patient who has started on treatment that prolongs the QT interval, and in that case you would
want to monitor the QT interval in sinus rhythm for at least 24 hours.
If we can learn to tailor outpatient therapy and only admit people who really need hospitalization,
it's good for the patient and it's good for the general health bill for the country.
I think if we pay attention to both these areas, preventing the episodes as best we can by paying
more attention to preventive medicine, and once the patient has been diagnosed with AF, really thinking
it through carefully on how to minimize occurrences and avoid admittance to the hospital, I think
will make a large step forward in the management of AF for the patient and society.sourse medscape
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