Diagnosis of Atrial Fibrillation

Patient History and Physical Examination

The initial diagnostic workup for patients with first detected atrial fibrillation (i.e., when the health care provider first becomes aware of the patient's atrial fibrillation) focuses on the following areas:

• Patient History

  • type of symptoms associated with atrial fibrillation
  • when symptoms first started
  • how long symptoms last
  • how frequently symptoms occur
  • any factors that may precipitate symptoms
  • any factors that may terminate symptoms
  • previous medication history
  • clinical classification of atrial fibrillation (e.g., first episode; paroxysmal; persistent; permanent)

• Physical Examination - The goal of the physical examination is to determine whether the patient may have another underlying condition that is the root cause of the atrial fibrillation. In performing the physical examination, the health care provider will look for signs of:

  • atherosclerosis and heart failure (e.g., arterial bruits; jugular vein distension; swelling of the extremities)
  • rheumatic heart disease/mitral stenosis
  • hypertension
  • hyperthyroidism

Laboratory Evaluation

Laboratory studies (e.g., blood tests) are done to check for the presence of underlying conditions which may trigger the atrial fibrillation. These tests may include:

• Electrolyte levels (e.g., potassium, sodium)
• Magnesium levels
• Blood glucose levels - to check for diabetes
• Blood Urea Nitrogen (BUN) - a test of kidney function
• Complete blood count
• Thyroid function tests
• Cardiac enzymes (evaluation of an acute event)
• Blood alcohol level (if deemed appropriate, in an acute event)

Diagnostic Studies

• Electrocardiogram (EKG)
• 24 hour Holter Monitor
• Transesophageal echocardiography (TEE)

An electrocardiogram (EKG) is a test that measures and records the electrical activity of the heart. An EKG not only confirms the presence of atrial fibrillation but also reveals other useful information such as a previous heart attack and/or hypertrophy (an abnormal enlargement) of the left ventricle.

In cases of persistent atrial fibrillation, the diagnosis can usually be established based on the patient's symptoms and an abnormal EKG that shows irregularities in the heart's electrical conduction system. In patients with paroxysmal atrial fibrillation, intermittent episodes of atrial fibrillation that may last from minutes to hours, the diagnosis of atrial fibrillation can usually be established with a Holter monitor (a device that continuously records the heart's rhythm for 24-hours) or with a patient-activated event monitor (a device that the patient wears continuously for several weeks and activates only when they begin to experience symptoms of atrial fibrillation).

Transesophageal echocardiography (TEE) is a unique test that uses sound waves to produce images of the heart valves and chambers and helps doctors evaluate how effectively the heart is pumping. Transesophageal echocardiography is also useful for identifying those patients with atrial fibrillation who may be at high risk for stroke.

In the diagnostic workup of patients with signs and symptoms of suggestive of an arrhythmia, it is important for the physician to distinguish between atrial fibrillation and atrial flutter. In atrial flutter, there is also rapid firing of the electrical impulses as in atrial fibrillation that causes the atria to beat around 300 times per minute while the ventricles beat at a much slower rate of about 75 to 150 beats per minute. The signs and symptoms of atrial flutter are similar to those of atrial fibrillation and include palpitations, shortness of breath, and dizziness. Atrial flutter can usually be distinguished from atrial fibrillation with an EKG. Complications of atrial flutter are similar to those of atrial fibrillation and include congestive heart failure, heart attack, and stroke.