Atrial Fibrillation and Preventing a Stroke

Dr. Milan Gupta, MD, FRCPC, FACC, Cardiologist

Atrial fibrillation, commonly known as AF, is quite a common electrical disturbance, in which the heartbeat becomes irregular and, often, fast. The main problem with AF is that blood clots can form inside the heart, and if that happens, then pieces of those clots can break off and travel to the brain, resulting in stroke. We know that patients with AF have about a fivefold increased risk of stroke compared to the general population, and many of those patients who experience stroke due to AF are left disabled or, even, die. The best way to prevent a stroke in AF is to use a class of medications called anticoagulants.

Anticoagulants are a class of medication commonly known as blood thinners. These drugs thin the blood. They usually do so in a predictable manner, and by doing that, we can prevent clots from forming in the heart. If we can prevent clots in the heart, we can prevent stroke due to atrial fibrillation.

While anticoagulants are very effective drugs, they are also powerful drugs because they thin the blood, and therefore it is critically important that patients take these agents exactly as their physicians have prescribed them. They need to be taken daily (some of them need to be taken twice daily), and it is very important that you don’t miss a single dose. If you miss a dose of anticoagulants, then for a certain period of time, your blood is not thinned, and as a result, your risk for a stroke rises. Also, if you don’t take anticoagulants as prescribed, your blood could potentially become too thin, resulting in major bleeding. Thus compliance with staying on these medications is so important, because if you take these drugs as prescribed, your stroke risk can be reduced by as much as 70%. We are fortunate that we have four different blood thinners available to us for the management of stroke prevention. The oldest drug, which we have used for over 40 years, is called Warfarin (or Coumadin). It is a very effective drug, but it has a number of nuances to it. The first is that patients need to have blood tests done usually once a month for the rest of their lives to regulate the dose of Warfarin. The second nuisance with Warfarin is that there are certain dietary restrictions, particularly relating to green, leafy vegetables. Having said that, Warfarin is an effective agent.

We have newer agents that have become available in the last five to seven years that in many ways are better than Warfarin. They provide predictable blood thinning, so you don't need blood testing on a regular basis, there are no food interactions, they do have a slight advantage in preventing stroke, and they are safer with respect to major bleeding.

One of these new agents is taken once daily, the other two are taken twice daily. All three are very effective options now for stroke prevention. It's important to remember that the vast majority of strokes in atrial fibrillation can be prevented through adequate, well-selected anticoagulation. Therefore, if you have more questions about this topic, it's important that you speak with your family physician or your cardiologist, so that you and your team of health care professionals can select the right drug for you.

Presenter: Dr. Milan Gupta, Cardiologist, Brampton, ON

Local Practitioners: Cardiologist