Atrial Fibrillation - Diagnosis - Diagnosis

To help diagnose atrial fibrillation, your doctor will ask about your eating and physical activity habits, family history, and other risk factors for atrial fibrillation and heart disease. Your doctor may ask whether you have any other signs or symptoms. This information can help your doctor determine whether you have complications or other conditions that may be causing you to have atrial fibrillation.

Your doctor will do a complete examination of your heart and lungs, including:

• Checking for signs of too much thyroid hormone, such as a thyroid gland that is larger than normal
• Checking for swelling in your legs or feet, which could be a sign of heart failure or a heart that is larger than normal
• Checking your pulse to find out how fast your heart is beating
• Listening to the rhythm of your heartbeat
• Listening to your lungs to check for signs of heart failure or infection
• Measuring your blood pressure

To diagnose atrial fibrillation, your doctor will likely do an EKG first to record your heart’s electrical activity. Data from a pacemaker or implanted defibrillator may also be helpful. If the diagnosis is unclear from the EKG or your doctor would like more information, your doctor may order additional testing:

• Blood tests to check the level of substances in the blood, such as potassium and thyroid hormone. This can help find the cause of your atrial fibrillation and show how well your liver and kidneys are working, which can help your doctor decide which medicines are most appropriate.
• Echocardiography to show areas of poor blood flow to the heart, areas of heart muscle that are not contracting normally, and previous injury to the heart muscle caused by poor blood flow. It may also identify harmful blood clots in the heart’s chambers.

Your doctor may order other tests to record abnormal heart rhythms that happen under specific conditions or outside of the clinic, confirm whether you have atrial fibrillation or another arrhythmia, and figure out which treatment is best. These tests may include:

• Chest X-ray to look for signs of complications from atrial fibrillation, such as fluid buildup in the lungs or a heart that is larger than normal.
• Electrophysiology study (EPS) to record your heart’s electrical signals if your doctor wants more detail about what is causing a particular EKG reading or to distinguish among possible types of arrhythmias.
• Holter and event monitors to record your heart’s electrical activity over long periods of time while you do normal, day-to-day activities. These portable EKG monitors can help assess the cause of symptoms, like palpitations or feeling dizzy, that happen outside the doctor’s office. Most portable monitors will send data directly to your doctor.
• Loop recorder to record the heart’s electrical activity. Some loop recorder models are worn externally and some require minor surgery to place the device under the skin in the chest area. Implanted devices can record data for months and are used to detect patterns in abnormal heart rhythms that do not happen very often.
• Sleep study to see if sleep apnea is causing your symptoms.
• Stress test or exercise stress test to look at changes in your heart’s activity that occur with increase in heart rate, and recovery after exercise. If you cannot exercise, you may be given medicine to make your heart work hard and beat fast.
• Transesophageal echocardiography (TEE) to detect blood clots that may be forming in the heart’s upper chambers because of atrial fibrillation. It uses sound waves to take pictures of your heart through the esophagus.
• Walking test to measure your heart activity while you walk for six minutes. This can help determine how well your body can control your heart rate under normal circumstances.

• Return to Risk Factors to review family history, lifestyle habits, or other medical conditions that increase your risk of developing atrial fibrillation.
• Return to Signs, Symptoms, and Complications to review common signs and symptoms of atrial fibrillation.
• Return to Screening and Prevention to review how to screen for atrial fibrillation.