To diagnose your condition and determine the specific type of tachycardia, your doctor will evaluate your symptoms, conduct a thorough physical examination, and ask you about your health habits and medical history.
Several heart tests also may be necessary to diagnose tachycardia.
An electrocardiogram, also called an ECG or EKG, is the most common tool used to diagnose tachycardia. It's a painless test that detects and records your heart's electrical activity using small sensors (electrodes) attached to your chest and arms.
An ECG records the timing and strength of electrical signals as they travel through your heart. Your doctor can look for patterns among these signals to determine what kind of tachycardia you have and how abnormalities in the heart may be contributing to a fast heart rate.
Your doctor may also ask you to use portable ECG devices at home to provide more information about your heart rate. These devices include:
Holter monitor. This portable ECG device is carried in your pocket or worn on a belt or shoulder strap. It records your heart's activity for an entire 24-hour period, which provides your doctor with a prolonged look at your heart rhythms.
Your doctor will likely ask you to keep a diary during the same 24 hours. You'll describe any symptoms you experience and record the time they occur.
Event monitor. This portable ECG device is intended to monitor your heart activity over a few weeks to a few months. You wear it all day, but it records only at certain times for a few minutes at a time.
With many event monitors, you activate them by pushing a button when you experience symptoms of a fast heart rate. Other monitors automatically sense abnormal heart rhythms and then start recording. These monitors allow your doctor to look at your heart rhythm at the time of your symptoms.
Your doctor may recommend an electrophysiological test to confirm the diagnosis or to pinpoint the location of problems in your heart's circuitry.
During this test, a doctor inserts thin, flexible tubes (catheters) tipped with electrodes into your groin, arm or neck and guides them through your blood vessels to various spots in your heart. Once in place, the electrodes can precisely map the spread of electrical impulses during each beat and identify abnormalities in your circuitry.
Imaging of the heart may be performed to determine if structural abnormalities are affecting blood flow and contributing to tachycardia.
Types of cardiac imaging used to diagnose tachycardia include:
- Echocardiogram (echo). An echocardiogram creates a moving picture of your heart using sound waves. An echo can identify areas of poor blood flow, abnormal heart valves and heart muscle that's not working normally.
- Magnetic resonance imaging (MRI). A cardiac MRI can provide still or moving pictures of how the blood is flowing through the heart and detect irregularities.
- Computerized tomography (CT). CT scans combine several X-ray images to provide a more detailed cross-sectional view of the heart.
- Coronary angiogram. To study the flow of blood through your heart and blood vessels, your doctor may use a coronary angiogram to reveal potential blockages or abnormalities. It uses a dye and special X-rays to show the inside of your coronary arteries.
- Chest X-ray. This test is used to take still pictures of your heart and lungs and can detect if your heart is enlarged.
Your doctor may recommend a stress test to see how your heart functions while it is working hard during exercise or when medication is given to make it beat fast.
In an exercise stress test, electrodes are placed on your chest to monitor heart function while you exercise, usually by walking on a treadmill. Other heart tests may also be performed in conjunction with a stress test.
Tilt table test
This test is sometimes used to help your doctor better understand how your tachycardia contributes to fainting spells. Under careful monitoring, you'll receive a medication that causes a tachycardia episode.
You lie flat on a special table, and then the table is tilted as if you were standing up. Your doctor observes how your heart and nervous system respond to these changes in position.
Your doctor may order additional tests as needed to diagnose an underlying condition that is contributing to tachycardia and judge the condition of your heart.