New blood thinners for common heart irregularity—atrial fibrillation

New blood thinners for common heart irregularity—atrial fibrillation


We expect our hearts to beat at a regular rate. The number of beats per minute varies, but still, there should be a regular rhythm.  In some people, their rhythm is not regular. The most common irregularity is called “atrial fibrillation (AF)”.

In many people their AF can come and go, but if it is a persistent problem—not controlled by other treatments— the patient is usually put on a daily blood thinner pill. For over 50 years, the blood thinner of choice has been warfarin (brand name Coumadin). 

Coumadin has many problems and risks, so fortunately, newer drugs have been developed that are safer and probably more effective. But many people are still on Coumadin, when they could be switched to one of the newer medications.

What is atrial fibrillation?

The heart has 4 chambers, or cavities. The two smaller upper ones, the atria, pump the blood to the two lower chambers, which pump the blood throughout the body. The contractions are stimulated by an electrical signal that begins in the atria. Sometimes the signal becomes disorganized, and the atria contract rapidly and irregularly (fibrillation). These signals then go to the ventricles, which beats much faster than usual. 

What are the symptoms?

Some people may have no symptoms at all, but commonly, a person with AF will notice that their heart “skips a beat” or “flip-flops” in their chest. Often a person will notice their heart is beating much too fast. If the fibrillation continues, some people will be fatigued or out of breath. 

How common is AF?

It is relatively common, affecting 2% of people below age 65, and 9% of people older. The rate is even higher for people in their 80s and above. 

Why do people with AF need blood thinners?

The upper chamber of the heart—the two atria—should be contracting, but in AF are quivering and not contracting fully. Some blood can then stagnate in the atria, and if it stays there, form clots. These clots can break off and travel to other parts of the body, such as the brain, causing a stroke. People with AF are 5 times more likely to have a stroke, but if their blood is thinned, the risk of clots and a stroke are much reduced. 

Problems with Coumadin

Coumadin is not an easy drug to manage. If a person has too much, they may bleed elsewhere, such as in their stomach. If the coumadin level is too low, they still might form clots in the heart. The coumadin level is affected by certain foods and interacts with many other medications, so a person on Coumadin needs frequent blood tests to check their “Coumadin level”.

The new drugs are better

The new drugs are called “novel oral anticoagulants” (NOACs) and include dabigatran, rivaroxban, and others. They probably work even better than Coumadin to prevent strokes, with much lower risk. Interactions with other medications is not such a problem, and frequent blood testing is not necessary.

What to do

If you are on Coumadin, ask your doctor if you can switch to a NOAC. There are still people (such as those with artificial heart valves) who require Coumadin, but the only way to know is to talk to your doctor, preferably a cardiologist. 

To find a doctor, of any specialty, anywhere in Brazil, check out our website:

See also in ProcuraMed:

Heart attacks in women may present with different symptoms

The power of green tea to protect your heart

Esta postagem também está disponível em: Portuguese (Brazil)

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