Diagnosis

Your doctor will evaluate your symptoms, perform a physical examination, and ask you about your health habits and medical history. In some cases, ventricular tachycardia may be a medical emergency that requires urgent diagnosis and treatment.

Several tests may be done to diagnose ventricular tachycardia.

Electrocardiogram (ECG)

An electrocardiogram (ECG or EKG) is the most common tool used to diagnose tachycardia. The painless test 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 the signals to determine what kind of tachycardia you have and how problems in the heart may be causing a fast heart rate.

Your doctor may also ask you to use a portable ECG device at home to obtain more information about your heart rate. These devices include:

• Holter monitor. You carry this portable ECG device in your pocket or wear it on a belt or shoulder strap. It records your heart's activity for an entire 24-hour period, which gives your doctor 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 have and record the time they occur.
• Event monitor. This portable ECG device is intended to monitor your heart activity over a week to a few months. You wear it all day, but it records only at certain times for a few minutes at a time. You typically activate the monitor by pushing a button when you have symptoms of a fast heart rate. However, some monitors automatically sense abnormal heart rhythms and then start recording.
• Other monitors. Some personal devices, such as smart watches, offer electrocardiogram monitoring. Ask your doctor if this is an option for you.
• Transtelephonic monitor. This device provides continuous heart rhythm monitoring but must be worn continuously. It may or may not include wires.
• Implantable loop recorder. This is an implantable device that has no wires and can sit underneath your skin for up to three years to continuously monitor your heart rhythm.

Electrophysiological test

Your doctor may recommend an electrophysiological test to confirm the diagnosis or to pinpoint the location of problems in your heart.

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.

Cardiac imaging

Your doctor may get images of your heart to determine if structural problems are affecting blood flow and causing your ventricular tachycardia.

Cardiac imaging tests used to diagnose ventricular tachycardia include:

• Echocardiogram. An echocardiogram creates a moving picture of your heart using sound waves. It can identify areas of poor blood flow, abnormal heart valves and heart muscle that are 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.

Stress test

Your doctor may recommend a stress test to see how your heart works when you are active or when medication is given to make the heart beat faster.

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 be done along 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 notes how your heart and nervous system respond to these changes in position.

Additional tests

Your doctor may order additional tests as needed to diagnose an underlying condition that is contributing to ventricular tachycardia and judge the condition of your heart.