What diagnostic test is commonly used to confirm atrial fibrillation?

The electrocardiogram (ECG) is the standard diagnostic test used to confirm atrial fibrillation. This test records the electrical activity of the heart and provides critical information about heart rhythms. In the case of atrial fibrillation, the ECG will typically reveal characteristics such as a lack of distinct P waves and an irregularly rapid ventricular response. This distinct pattern allows healthcare providers to accurately diagnose atrial fibrillation and differentiate it from other types of arrhythmias.

Other diagnostic options mentioned, such as a chest X-ray, MRI, or stress test, serve different purposes and do not provide the specific electrical activity data necessary to confirm atrial fibrillation. A chest X-ray is useful for assessing the size and shape of the heart and lungs, while an MRI can provide detailed images of cardiac structures but does not measure heart rhythm. A stress test focuses on how the heart performs under physical stress, which may provide additional context for overall heart health but does not confirm atrial fibrillation itself.