What Your Heartbeat Might Mean for Risk of StrokeJul 29, 2014
Dr. Miller: Atrial fibrillation and stroke, are they related and can it be treated? Today on Scope radio, this is Dr. Tom Miller.
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Dr. Miller: I am here today with Dr. Dana DeWitt. She is a professor in neurology and a stroke specialist in the University of Utah, the department of Neurology. Dana, tell us a little bit but atrial fibrillation, what is it and does it lead to stroke? Can it cause stroke?
Dr. DeWitt: Atrial fibrillation is an irregular heartbeat. It causes a portion of the heart, called atrium to contract in a very irregular manner and when that happens, clot can form in that portion of the heart and break off and go up to the brain and cause a stroke. It is clearly a major risk factor for stroke.
Dr. Miller: Atrial fibrillation, in my experience, is more common in older patients and older people, and sometimes goes unnoticed. Many times its picked up on a routine physical and sometimes in E.K.G. or patients who complain of palpitations which when you look into it, turns out to be atrial fibrillation. The issue that I have is, in telling the patient, well it's not just this irregular heart rhythm but you might have a stroke down the road if we don't take care of this. In your experience, how many of these strokes that you see, when they come in through the emergency room due to atrial fibrillation.
Dr. DeWitt: It's a fairly large proportion, probably a quarter at least. The hard part is that in many cases, patients will come in and having had a stroke, not have atrial fibrillation at the time so the atrial fibrillation can be intermittent and can sometimes be difficult to detect.
Dr. Miller: How do we detect for atrial fibrillation nowadays? What's the best way?
Dr. DeWitt: When the patient comes in and he has had a stroke, they are usually in a hospital with a cardiac monitor that watches their heart rhythm during that hospitalization. The problem is that the atrial fibrillation may not be detected during that time and so we may recommend, what we call the 30 day event monitor, which is an E.K.G. monitor that they wear for 30 days. There are also things that are called loop recorders which are these very small implantable devices that are M.R.I. compatible and they are put in by the cardiologist just over the heart with a very minor office procedure, and it monitors your heart over time.
Dr. Miller: So potentially, it can pick up intermit atrial fibrillation.
Dr. DeWitt: Exactly, which carries a high risk of stroke.
Dr. Miller: Now, many of our patients and public know that to prevent a stroke, you take an aspirin a day. Does that work to prevent stroke in atrial fibrillation?
Dr. DeWitt: It has not proven to be effective enough in patients with atrial fibrillation. The best treatment are blood thinners, and now blood thinners come in two different forms. There is a drug called Warfarin which is being used for many, many years.
Dr. Miller: That's rat poison. Isn't it?
Dr. DeWitt: It is rat poison and it is the primary treatment for atrial fibrillation to prevent stroke. The problem with warfarin is, that it requires regular blood test monitoring. There are some dietary interactions like green leafy vegetables that have to be regulated.
Dr. Miller: Antibiotics, if you take antibiotics, seizure drugs.
Dr. DeWitt: Antibiotics, drugs for seizure. There are many interactions and you have to blood test regularly to make sure your dosing is correct. If your dosing is too low then it doesn't protect you, if your dosing is too high, it could cause hemorrhage and this actually leads to a lot of fear sometimes, in not treating patients who are either elderly or might be falling.
Dr. Miller: Or who can't get their testing.
Dr. DeWitt: Who can't get their test done?
Dr. Miller: I know a number of physicians who are uncomfortable treating atrial fibrillation with warfarin. Just because of it narrow window of therapy [inaudible 00:04:00]. That's a big deal, that's a problem. If you have a team of experts, and many times those are pharmacists who take on that monitoring, that's a pretty good way to assure that the patient remains within the therapeutic window. We, at the University of Utah, taken that out of the hands of the physicians if they want us to and monitor that through our [inaudible 00:04:21], and that's have been a very effective way to manage warfarin. Warfarin is not expensive but the monitoring is key. Would you say that's true?
Dr. DeWitt: Absolutely. I tell patients who are on warfarin, the important things is really getting their blood test regularly. There are three new oral agents that have been shown to be effective for treating atrial fibrillation.
Dr. Miller: They are pricey, aren't they?
Dr. DeWitt: They are very pricey because they have a standard dosing and you don't need to do blood test. They have been a bit attractive. The problem is that, a lot of times, the patients are not able to be monitored as well if they do have a stroke, so they may not be a candidate for a thrombolytic agent. In many cases, we just don't feel totally comfortable with them as we are with warfarin in many cases.
Dr. Miller: The problem that I have in practice is, either the cost of neural medication is too much for the older person to afford or the fact that they have to be able to come in for testing and monitoring on a regular basis, whether it's by myself or a team. So there are pluses and minuses with each type of treatment.
Dr. DeWitt: I think the important thing though is that we know that atrial fibrillation is a big factor in stroke. In many cases, it's not just the monitoring but the impression, because the patients are getting older or because they are a little unsteady on their feet, that they shouldn't be treated with anti-coagulation and unfortunately, we are the ones who see those patients come into the hospitals with their big strokes.
Dr. Miller: And aspirin is not enough.
Dr. DeWitt: Aspirin is not enough.
Dr. Miller: Dana, final thoughts?
Dr. DeWitt: Well, I think the important thing is that, with strokes of certain types we suspect clot form the heart and even if we don't pick up atrial fibrillation, I think it's important to monitor the heart and keep looking for it and treat it appropriately.
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