What is Atrial Fibrillation?
Atrial fibrillation is a very common heart disease characterized by an abnormal heart rhythm. Patients may experience palpitations (heart pounding), chest pain, dizziness, and loss of consciousness. The heart rate may be elevated (>100 bpm), slow (<60 bpm), or within the normal range.
This condition can be very serious, leading to a drop in blood pressure and even stroke. Given its seriousness, it is important for patients to educate themselves about the causes and treatment of atrial fibrillation.
What Causes Atrial Fibrillation?
Atrial fibrillation can be caused by a myriad of conditions. The most common conditions leading to atrial fibrillation include:
- Heart attack
- Pulmonary embolism (blood clot in the vessels of the lung)
- Hyperthyroidism (overactive thyroid gland)
- Drug or alcohol use – cocaine, amphetamines
- Electrolytes abnormalities
- Excessive caffeine intake
- Certain medications
This condition may also occur in individuals that are genetically predisposed due to family history of atrial fibrillation.
These factors cause the atria (upper chambers of the heart) to beat irregularly in an uncontrolled manner.
How Common is Atrial Fibrillation?
Atrial fibrillation is the most common type of arrhythmia (abnormal heart rhythm) seen in clinical practice and is a frequent cause of visits to the emergency department. It affects about 2.2 million people in the United States. Elderly men are most commonly affected, but the condition may also be seen in women and young individuals.
Signs and Symptoms
The most common symptoms of atrial fibrillation include:
- Shortness of breath
- Chest pain
- Loss of consciousness
These symptoms occur because the heart beats erratically. This can lead to poor blood flow to the heart, which causes chest pain and shortness of breath. Decreased blood flow to the brain may also result in dizziness and loss of consciousness.
One of the most worrisome consequences of atrial fibrillation is stroke. When the atria are moving irregularly, this causes blood to become stagnant and form clots. Blood clots in the left atrium may eventually dislodge and block off blood supply to the arteries of the brain. When blood supply to the brain is cut off for long enough (usually at least 5 minutes), brain tissue dies, causing symptoms of stroke such as paralysis.
Atrial fibrillation is diagnosed based on symptoms, physical examination, and electrocardiogram (EKG). EKG is very valuable in this setting because it shows the electrical activity of your heart and can determine whether your symptoms are caused by atrial fibrillation or another abnormal heart rhythm. It also helps rule out one of the most worrisome causes of atrial fibrillation – heart attack.
Besides an EKG, your doctor will likely order a chest x-ray to get a picture of your heart size and evaluate for structural abnormalities in the lungs. They will also usually obtain an echocardiogram – ultrasound of the heart – to evaluate your heart’s structure and function.
Lastly, your doctor will typically get blood tests to check your electrolytes, thyroid function, and heart muscle enzymes to evaluate for cardiac injury such as heart attack. Occasionally, a urine drug screen will be ordered as well.
If your doctor suspects that you have a pulmonary embolism, they might order a test called a CT angiogram – this evaluates for blood clots in the blood vessels of the lung.
Atrial Fibrillation Medication and Treatment
The acute treatment of atrial fibrillation depends on whether or not it is an emergency. If your heart rate is significantly elevated, your blood pressure is very low, and you are not getting adequate blood supply to your brain, they may cardiovert or “shock” your heart back to a normal rhythm.
If it is not an emergency and your heart rate is significantly elevated, they will likely administer an intravenous medication to slow down your heart rate. These medications may include:
- Beta blockers
- Calcium channel blockers
- Lanoxin (digoxin)
Eventually, your doctor will likely transition these intravenous medications to an oral formulation.
Depending on your risk factors (e.g., history of heart failure, hypertension, advanced age, diabetes, stroke), your doctor may also start you on an oral blood thinner medication such as Coumadin (warfarin).
Warfarin interacts with a host of medications and foods (e.g., spinach). This medication also needs to be monitored very closely with regular blood tests – therefore, a lot of patients are started on newer oral anticoagulants such as:
Occasionally, your cardiologist may attempt to bring your heart back to normal rhythm instead of simply reducing your heart rate. Before attempting this, they may have to perform a transesophageal echocardiogram to check if you have a blood clot in the left atrium. This procedure is performed under mild sedation, and a camera is directed down your esophagus to visualize your left atrium from behind.
Cases that are refractory to medical therapy may require the use of interventional procedures such as cardiac ablation. During this procedure, your cardiologist will access your heart through an artery in the groin or arm. They will then attempt to cauterize the area of your heart that is responsible for atrial fibrillation.
- January CT, Wann LS, Alpert JS, et al. 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines and the Heart Rhythm Society. Circulation. 2014 Dec 2;130(23):2071-104. - https://www.ncbi.nlm.nih.gov/pubmed/24682348
- Xu J, Luc JG, Phan K. Atrial fibrillation: review of current treatment strategies. J Thorac Dis. 2016 Sep;8(9):E886-E900. - https://www.ncbi.nlm.nih.gov/pubmed/27747025
- Copley DJ, Hill KM. Atrial Fibrillation: A Review of Treatments and Current Guidelines. AACN Adv Crit Care.2016 Feb;27(1):120-8. - https://www.ncbi.nlm.nih.gov/pubmed/26909462
The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.