If your doctor suspects that you have supraventricular tachycardia, she might have you take some tests to find out for certain what’s causing your heart to beat so rapidly sometimes.
The results will let your doctor know what exact type of SVT you have -- if that’s even what it is -- so she can choose the best way to deal with it. Then you can be on the way toward ending your light-headedness, chest pain and other symptoms.
What Is It, Exactly?
SVT is a group of heart conditions that all have a few things in common.
The term has Latin roots. Supraventricular means “above the ventricles,” which are the lower two sections of your heart. Tachycardia means “fast heart rate.”
So the condition is a fast heart rate that’s caused by problems in electrical signals starting in the upper two sections of your heart, called the atria.
Other conditions can cause your heart to beat too fast. That means your doctor will need all the details of your symptoms. She’ll also do a physical exam and record your heartbeats to be sure of the diagnosis.
Patient History and Exam
Your doctor will ask you detailed questions to help figure out what tests to run.
She will want to know how old you were when you first noticed a problem. She’ll also ask when and how your symptoms began. That includes whether you were exercising when you noticed things such as a rapid pulse, dizziness or a hard time breathing.
Other things she’ll ask you about:
- Whether the symptoms came on suddenly or slowly
- What they feel like to you and how long they tend to last
- Whether you’ve noticed that you’ve had a fast heartbeat after caffeine or stress
- Whether you or anyone in your family has had heart problems or procedures
During your exam, your doctor probably will listen to your heart and lungs with a stethoscope. She might also:
- Feel your thyroid gland on your neck
- Get your temperature and measure your blood pressure
- Take a small blood sample with a thin needle
If your doctor still suspects supraventricular tachycardia after hearing about your symptoms, examining you and running some basic tests, she might ask you to get an EKG. You may hear her call it an “electrocardiogram” or an ECG.
This test records your heart’s rhythm over time, so if it’s not beating as it should, it can reveal what the problem is. If you’re getting one, there’s nothing special you need to do ahead of time to get ready.
To set up the test, a nurse or technician will attach 12 to 15 sticky patches, called electrodes, to your chest. If you have a hairy chest, an aide may need to shave small areas so they stay put.
Each one will go with a wire that leads to a machine. During the test, which takes just a few minutes, you’ll be asked to lie still and breathe normally.
You might have symptoms just once in a while, so a single EKG in the doctor’s office may not reveal an abnormal heart rate.
In these cases, you might need to wear a device for longer so doctors can record your heart while you’re having symptoms. You may be sent home with one of the following:
A Holter monitor is a small, battery-powered EKG that records your heart’s activity for 24 to 48 hours. The device is about the size of a small camera and has little electrodes placed on your chest while you wear it. You can do most of your daily activities, but you shouldn’t bathe or shower.
An event monitor is also a portable EKG but might be more practical if you have symptoms less than once a day. You can wear it for longer than a Holter and press a button on it when you’re having symptoms. The monitor will record details only for the few minutes you’re feeling the fast heartbeat.
Your doctor may ask you to wear it for days or weeks.
If you’re diagnosed based on the results of an EKG, you may need more tests to figure out what type of SVT you have and what’s causing it.
Often, this can include what’s called an “electrophysiology study” so that doctors can learn in more detail how the different sections of your heart are sending electrical signals to each other.
For this test, you are sedated at a hospital or clinic and soft, flexible wires are passed through your veins into your heart. You will need someone to drive you to and from your appointment. Talk to your doctor about how to prepare because this test is more involved.