Atrial fibrillation is the most common heart abnormality requiring treatment in the United States. Denice Zingman, MD, UI Heart and Vascular Center cardiologist, talks about atrial fibrillation and new treatments available:

First, tell us what exactly is atrial fibrillation?

Atrial fibrillation is the number one heart rhythm disturbance in the United States. It will eventually affect one in four people over the age of 40. We currently, in the U.S., have a prevalence of about 2.2 million cases of atrial fibrillation and because it's predominately an age-related disease, this prevalence is expected to double in the next 35 years as our population ages.

Physically, it is disorganized electrical activity in the top chamber of the heart or atria. This causes the atria to quiver or fibrillate instead of beating regularly, causing the lower chambers, which are the ventricals, to beat irregularly and often at an excessive rate. The majority of symptoms from atrial fibrillation are caused by this irregularity and racing of lower pumping chambers, as well as decreased efficiency of the lower chambers which don't fill properly with blood due to the loss of priming affect from the atria.

This is not usually a fatal rhythm, however if it's not recognized early, it has several potential consequences that can be harmful or fatal, including, the most important being, blood clot formation in the upper chambers that can lead to stroke, but also decreased efficiency of the heart pumping function and rapid rates which can weaken the heart over time.

I want to mention that atrial fibrillation is predominately age-related, but it can be caused by other heart problems, most commonly heart failure, prior heart attacks, high blood pressure, valve disease, or congenital abnormalities such as atrial septal defect. It can be genetic and that's usually the cause when it occurs in young people. It also can be a consequence of thyroid disease or lung disease or other acute illnesses or postoperative states, particularly after heart surgery, and can occur after heavy alcohol consumption, as well.

Are women or men more likely to have this irregular heartbeat?

It's actually pretty close, the risk is about 26 percent for men and 23 percent for women over 40, but since we have more women in the older populations and because it's often an age-related disorder, it actually turns out that about 55 percent of the people who have atrial fibrillation are women, whereas 45 percent are men, so overall it's pretty close.

Is it associated with a heart attack or stroke?

Yes, atrial fibrillation is the number one cause of stroke, but it also can be associated with heart attacks. Now, atrial fibrillation is not sufficient by itself to cause a heart attack, but in people who already have blockages in their coronary arteries, the rapid heart rates and decreased pumping function that occur due to atrial fibrillation can cause a heart attack. And furthermore, if you've had heart attacks in the past, you're more likely to have atrial fibrillation, or during an acute heart attack, you're may have atrial fibrillation as well.

What are the symptoms of atrial fibrillation?

The most common symptoms would be palpitations, which is a fluttering or irregular heart beat; the sensation of your heart racing; weakness; fatigue; shortness of breath; decreased exercise tolerance. Some people may have light headedness or passing out and some people may have chest discomfort or chest pressure. Some people may have all of these symptoms or they may just have a few. And interesting, some people are completely unaware of atrial fibrillation and it's only diagnosed after they make a routine visit to their doctor, or if they're being seen in a doctor's office or emergency room for some other medical problem.

How is atrial fibrillation treated?

There are quite a number of treatments available and we often use a comprehensive strategy to address atrial fibrillation. The most important consideration is stroke risk reduction because of the serious morbidity and mortality associated with the stroke from atrial fibrillation. So the most effective way to do this is a give blood thinning agent and, depending on the patient's individual risk of stroke, the blood thinner selected would either be warfarin, which is Coumadin, for higher risk people, or aspirin for lower risk people. Otherwise, these treatment strategies are aimed to reduce the hemodynamic problems and the symptoms of atrial fibrillation.

So for most people, simply controlling the heart rate while allowing the atrial fibrillation to continue is sufficient, and this minimalist approach is often the safest approach. But, some people are very symptomatic with the atrial fibrillation or have weakened hearts or valve problems that are worsened by the atrial fibrillation and they just can't tolerate the rhythm. In that case, we try to get the patient back into a normal rhythm, and this can be achieved by several methods: we can temporarily sedate the person and give a shock to the heart to bring it back into a normal rhythm, we can use medications that suppress atrial fibrillation, or we can perform catheter ablations or surgical procedures to return the heart to normal rhythm.

In some extreme cases, we may have to place a pacemaker and cauterize the electrical connection between the upper and lower chambers in order to regularize the heart beat. Often it's a combination of these strategies. I'll just in mention catheter ablations and surgical procedures, these work on the principal of forming scars in the key areas of the atria and these scars are electrical insulators and so these appropriately places scars can prevent the abnormal electrical circuits that initiate and propagate atrial fibrillation. This strategy isn't appropriate for many patients, but it is a very effective treatment strategy in patients in whom other strategies have failed.

How new are some of these treatments?

One of the most important advancements is taking a comprehensive approach to atrial fibrillation as we recognize that it is a growing problem with serious morbidities and mortalities. The University of Iowa actually has a comprehensive approach to treatment of atrial fibrillation that consists of our internists, cardiologists, cardiac electrophysiologists, and cardiac surgeons working together. Actually, the University of Iowa is unique in Iowa in that we have all the latest and most current imaging and diagnostic treatment modalities available.

Among the treatments that I mentioned, the newest treatment is probably the catheter ablations for atrial fibrillation. That procedure has been around for a little over five years, but has really, in the past five years, improved quite a bit so that it's safer, more effective, and more applicable to greater numbers of patients. Surgical strategies are also improving so that they're less invasive and more effective, as well. In general, the catheter ablations and surgical procedures are the areas that I think are expanding the most rapidly.

Can a person be cured or can atrial fibrillation go away?

Atrial fibrillation, in some cases, can go away on its own and possibly not return depending on the cause, although that's the exception more than the rule. So an example of atrial fibrillation that may go away and not come back is if it's associated with a postoperative state, particularly after heart surgery; associated with either hyper- or hypothyroidism that's subsequently been treated; but usually atrial fibrillation, which may come and go, tends to become more persistent as time goes on, and so even if we can suppress atrial fibrillation, generally the stroke risk remains. So our strategy is to continually evaluate for conditions that exacerbate the atrial fibrillation and continue to use stroke prevention throughout a person's life once they've been diagnosed with atrial fibrillation.

Is UI Hospitals and Clinics involved in any research with regard to atrial fibrillation?

Yes, we actually are. We have several clinical trials ongoing. One of our electrophysiologists, Brian Olshansky, MD, is directing local participation in a national trial that examines the effects of dietary fish oil as a preventive strategy for postoperative atrial fibrillation. There are also several retrospective studies and treatment outcomes with catheter ablation techniques that are ongoing. And there are some planned trials of novel anticoagulants as alternatives to Coumadin for stroke prevention that will probably begin enrollment this year.

Another one of our electrophysiologists, James Martin, who is examining patients undergoing catheter ablation for atrial flutter to see if clusters of fractionated electrical signals, that have been noticed in the hearts of people with atrial fibrillation, can be seen in patients with other rhythm disorders that may predispose them to the development of atrial fibrillation in the future. And then, there are numerous investigators, including myself, who are working at the basic molecular level to better understand the etiology of atrial fibrillation and develop novel treatment strategies that will eventually be tested in clinical trials.

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