A-fib — atrial fibrillation — is the most common irregular heart rhythm found in adults. With this disorder, the electrical conductivity between the heart chambers becomes "jammed." The top chambers of the heart, known as atria, begin to fibrillate — contract quickly and erratically — rather than contract normally. This can make the heart rate go faster and disturb the normal flow of blood inside the heart.
An A-fib diagnosis is made by a physician and requires an electrocardiogram. This is done by applying electrodes to the chest and allows a look at the heart's electrical activity.
Atrial fibrillation can be associated with other health problems, so additional testing can be performed once A-fib is diagnosed. Many studies show the best way to treat A-fib is to control the heart rate from going too fast and to assess for the risk of blood clot formation.
The least invasive way to control the heart rate is medication that slows the heart. If rate control is not attained, or if symptoms persist, medicines to help restore a normal rhythm can be used.
Atrial fibrillation increases the likelihood that small blood clots can form spontaneously in the top chamber of the heart. Blood clots leaving the heart, known as embolism, can have serious consequences. One of the most feared complications is a clot going to the brain, causing a stroke.
Assessing risk of blood-clot formation requires an individualized approach. There are scoring systems that predict the risk of stroke based on the number of risk factors a person has, such as age or diabetes, and allows for an objective assessment of risk. If this risk is low, aspirin might be recommended. If the risk is higher, use of a blood thinner is recommended to lower the risk of stroke and systemic embolism.
Until recently, warfarin was the only anticoagulant, or blood thinner, proven to lower the risk of stroke in A-fib. Several other drugs such as dabigatran and rivaroxaban show similar rates of preventing stroke
Anticoagulants work by limiting the body's ability to clot, thus the risk of bleeding is increased. For each patient, the physician and patient weigh the risk of bleeding against the benefit of preventing a stroke.
Women have a higher stroke risk than men with the same risk factors. Over the years, women have been less likely to be prescribed anticoagulants than men and are less likely to take these medicines once prescribed. However, the benefit in stroke reduction is the same for both sexes, and given the higher risk of stroke, the overall benefit might be higher in women than in men.
If you have A-fib, discuss the pros and cons of these medications with your physician.