The diagnosis of atrial fibrillation is generally made with tests that record heart rhythm. Your doctor will also investigate the cause of AFib and evaluate your risk of complications.
Initial Evaluation
When you first visit your doctor, they will ask you questions about your symptoms. They will want to learn details such as when the heart palpitations started, how long they lasted, whether there are other symptoms. They will get information about whether there is a family history of AFib, your other health problems, and the medications you are taking.
During the physical examination, they will check your pulse. In AFib the pulse is irregular and this is usually the first clue. Your blood pressure will be measured, your heart will be listened to with a stethoscope. Your lungs will be checked and it will be seen whether there is swelling in your feet.
Electrocardiogram (ECG)
The ECG is the most important test for definitively diagnosing AFib.
The ECG records the electrical activity of your heart. Small electrodes are attached to your chest, arms, and legs. The device records your heart's electrical signals, creating lines on paper. The test is completely painless and takes only a few minutes.
The ECG shows whether your heart rhythm is regular or irregular. If there is AFib, a characteristic irregular pattern is seen. The test also shows your heart rate and whether there are other problems in the heart's electrical conduction.
However, the ECG has a limitation - it only shows the current state. If your symptoms come and go and there is no AFib at that exact moment, the ECG may come out normal.
Continuous Heart Rhythm Monitoring
If your symptoms come and go, longer-term monitoring may be needed. Portable ECG devices are used for this.
The Holter monitor is a small device that usually records your heart rhythm for 24-48 hours. The device is attached to your belt and connected to electrodes stuck to your chest. The device continuously records while you continue your normal activities. You are given a diary and asked to record when you feel symptoms.
The event recorder is used for longer-term monitoring. You can carry this device for weeks or months. When symptoms start, you press a button on the device and the heart rhythm at that moment is recorded. This way even rare attacks can be caught.
In some cases an implantable loop recorder may be needed. This is a small device placed under the skin that monitors your heart rhythm for 2-3 years. It is especially used in people with unexplained fainting or very rare symptoms.
Blood Tests
After AFib is diagnosed, blood tests are done to investigate underlying causes.
Thyroid function tests are definitely done because thyroid problems are a common cause of AFib. Kidney function tests are important because kidney health affects medication choice. Electrolyte levels, especially potassium and magnesium, are checked. Complete blood count shows conditions such as anemia. Blood sugar and HbA1c are checked for diabetes. Cholesterol levels are also evaluated.
Echocardiography
Echocardiography is ultrasound imaging of the heart and is very important in AFib evaluation.
Transthoracic echocardiography performed through the chest wall is the most common type. An ultrasound probe is placed on your chest and heart structures are visualized on the screen. The test is painless and takes approximately 30-45 minutes.
Echocardiography shows the size of the heart, the thickness of its walls, the functioning of the valves, and the heart's pumping strength. It evaluates whether the left atrium is enlarged, whether there are valve problems, and whether there is a clot in the heart.
In some cases, transesophageal echocardiography performed through the esophagus may be needed. This test provides more detailed images and is especially used to look for clots in the left atrial appendage. It is performed under light sedation and a short thin tube is passed through your esophagus. It may be done before procedures such as cardioversion to make sure there is no clot.
Other Tests
Chest X-ray may be taken to evaluate heart size and lung problems. If the heart is enlarged or fluid has accumulated in the lungs, this is seen.
Exercise test or stress test shows how your heart works during exercise. Your heart rhythm, rate, and blood pressure are monitored while you exercise on a treadmill or bicycle ergometer. This test helps evaluate coronary artery disease and can reveal AFib triggered by exercise.
Stroke Risk Assessment
When AFib is diagnosed, your doctor will calculate your stroke risk. A system called the CHA₂DS₂-VASc score is used for this.
In this scoring system, points are given for various factors. If there is heart failure 1 point, if there is high blood pressure 1 point, age 65-74 1 point, age 75 and over 2 points, if there is diabetes 1 point, if you have previously had a stroke or transient ischemic attack 2 points, if there is vascular disease 1 point, if you are female 1 point.
If the total score is 0, your stroke risk is low and blood thinners may not be needed. If the score is 1, you are at moderate risk and blood thinners may be considered. If the score is 2 and above, you are at high risk and anticoagulant treatment is definitely needed.
Bleeding Risk Assessment
If blood thinner treatment is being considered, your bleeding risk is also evaluated. The HAS-BLED score is used for this.
This scoring evaluates factors such as uncontrolled high blood pressure, kidney or liver function impairment, previous stroke, bleeding history, labile INR values, being over 65 years old, regular alcohol use, or use of certain medications.
Even if there is a high bleeding risk, the benefit of reducing stroke risk generally outweighs the bleeding risk. However, if there is high bleeding risk, more careful monitoring is done.
After Diagnosis
When the diagnosis is made, your doctor will tell you your AFib type - paroxysmal, persistent, or permanent. If there is an underlying cause, they will explain it. They will explain your risks of stroke and other complications.
Treatment options will be discussed in detail. Topics such as which medications are necessary, how often checkups are needed, what kinds of changes you should make in your lifestyle will be discussed.
A regular follow-up plan will be made. More frequent checkups may be needed in the first months, then appointments are planned at regular intervals. Follow-up is very important for medication adjustments, side effect monitoring, and early detection of complications.
Do not hesitate to ask your questions. Understanding AFib and actively participating in your treatment is important for success.