Making the Diagnosis
When the heart beats faster than normal, it's called tachycardia. AF is one type of tachycardia. If too many impulses are allowed through to the ventricles, your heart rate may be greater than 100 beats per minute. Conversely, if not many impulses are allowed through, your heart rate may, in fact, be slow.
The stethoscope is a valuable instrument when it comes to detecting arrhythmias like AF, but there are modern tests that can pinpoint the problem. The electrocardiogram (ECG) prints a graph of the heart's electrical activity using small electrodes taped to the chest. The pattern on these graphs reveals the type of arrhythmia and can help the doctor diagnose AF. Since the arrhythmia might not occur at the hospital, there are portable ECGs that you can bring home. Some are constantly turned on over a specified period of time (these are called Holter monitors), while others are turned on by you when you feel palpitations (these are called event monitors or loop recorders). Some of these devices can download the heart signal data over a phone line or mobile phone.
Electrophysiologic study (EPS) is a more elaborate test. Thin tubes are inserted into a blood vessel in the leg and guided up to the heart. They hold electrodes that can find the heart tissue that may be overriding the signals from the sinus node.
Your doctor may also order blood tests to determine if another condition (e.g., thyroid hormone imbalances) is associated with your AF.