Following a comprehensive health history, your doctor will begin a thorough physical exam by first listening to your heart and lungs with a stethoscope to get a sense of your heart and respiratory rate and rhythm. Some problems, such as heart murmurs, valve problems or fluid in the lungs, can be detected this way. Your doctor will also look for evidence of thyroid problems by feeling your thyroid gland to see if it is enlarged.2

Based on the information from your health history and results of your physical exam your doctor may want additional information in the form of imaging and laboratory tests to help evaluate your heart function. The following tests may be part of either a routine or a more advanced workup for AFib:


The standard test doctors use to diagnose Afib is an EKG, or electrocardiogram.1 This test uses painless electrodes placed on your chest that detect the electric currents that your heart uses to generate the rhythmic muscular contractions that pump blood through its chambers and out to your body. An EKG machine can record both the rhythm of your heart and the strength of each chamber’s contractions and timing of electrical signals as they pass through each part of your heart.

If AFib isn’t detected during an EKG, which generally lasts only a few minutes, you may need to wear a portable EKG monitor to get an accurate evaluation of your heart function over several days, weeks or months. There are two types of portable EKG devices: Holter monitors, which are used in instances where symptoms generally occur on a daily basis, and event monitors, which are used when symptoms are less frequent or predictable.1

Stress Test

In some instances, a stress test may be performed. This type of test is helpful to diagnose forms of AFib that occur mainly or frequently during times of increased physical activity. Or, your doctor may be interested in seeing how your heart functions under stress and how your AFib symptoms are affected by physical activity. A standard stress test shows changes in your heart's electrical activity. It also can show whether your heart is getting enough blood during exercise. A standard exercise stress test uses an EKG (electrocardiogram) to detect and record the heart's electrical activity.1 One type of imaging stress test involves echocardiography (echo). This test uses sound waves to create a moving picture of your heart. An exercise echo can show how well your heart’s chambers and valves are working when your heart is under stress.3


A form of ultrasound, echocardiography directs sound waves at your heart. As the sound waves bounce off the different heart structures they are picked up by a monitor, which converts them into a 2 or 3-dimensional image of your heart’s size and shape in real time. Your doctor can use echocardiography to determine how effectively your heart’s chambers and valves are functioning and when and where your heart might be experiencing problems in conveying impulses and coordinating contractions.1

Transesophageal Echocardiography

Your atria are thin, delicate structures that are located in the center of your chest behind the bony protection of your ribs and sternum (breastbone). For these reasons it can be difficult to obtain precise images with regular echocardiography. If your doctor needs to get a better view of your atria he or she might suggest a transesophageal echocardiography procedure, or TEE. For this test the sound wave device, known as a transducer, is passed through your esophagus until it reaches a place that is close to your heart. Because TEE is more precise at imaging the atria it is also useful for detecting small blood clots that occasionally develop from AFib and that might otherwise go unnoticed.1

Chest X-Ray

A chest x ray is a painless test that creates pictures of the structures in your chest, such as your heart and lungs. This test can show fluid buildup in the lungs and other complications of Afib.1

Blood Tests

Routine blood screening panels can reveal if your blood glucose is out of range, as well as provide a glimpse into your thyroid hormone levels. Additionally, certain essential minerals or vitamins, such as vitamin D, serve important roles in maintaining healthy fluid levels and proper cell-to-cell communication throughout your body. Blood work can tell your doctor if those levels are too low or too high.1

If you are concerned that you might have AFib, search for a local doctor by entering your zip code to the right and make an appointment. They will be able to determine which tests are appropriate after taking your health history. Review this checklist of questions for the doctor before speaking with them.

If you still have questions, check out the Frequently Asked Questions page.

1Cardiac Surgery, UCSF, Atrial Fibrillation.
2Cedars-Sinai, Atrial Fibrillation,
3Stress testing, NIH, US Department of Health & Human Services. NHLBI, 2018.

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The NAVISTAR® THERMOCOOL®, EZ STEER® THERMOCOOL® NAV, THERMOCOOL® SF NAV, and THERMOCOOL SMARTTOUCH® Catheters are FDA approved for the treatment of drug refractory recurrent symptomatic paroxysmal atrial fibrillation, when used with compatible three-dimensional electroanatomic mapping systems. Catheter ablation for AF may not be an option for you if you have any of the following conditions: certain recent heart surgery; prosthetic valves; active systemic infection; certain cancers; intracardiac thrombus, or an interatrial baffle or patch. Consult your physician to find out if catheter ablation is right for you.

As with any medical treatment, individual results may vary. Only a cardiologist or electrophysiologist can determine whether ablation is an appropriate course of treatment. There are potential risks including bleeding, swelling or bruising at the catheter insertion site, and infection. More serious complications are rare, which can include damage to the heart or blood vessels; blood clots (which may lead to stroke); heart attack, or death. These risks need to be discussed with your doctor and recovery takes time.

THERMOCOOL® Navigation Catheters are indicated for the treatment of recurrent drug/device refractory sustained monomorphic ventricular tachycardia (VT) due to prior myocardial infarction (MI) in adults.