Tests and diagnosis

By Mayo Clinic Staff

Your doctor will order a series of tests to measure your heart rate, establish a link between a slow heart rate and your symptoms, and identify conditions that may be causing bradycardia.

Electrocardiogram (ECG)

An electrocardiogram — also called an ECG or EKG — is a primary tool for evaluating bradycardia. An ECG uses small sensors (electrodes) attached to your chest and arms to record electrical signals as they travel through your heart. Your doctor can look for patterns among these signals to determine what kind of bradycardia you have.

Your doctor may also have you use a portable ECG device at home to provide more information about your heart rate and to help establish a correlation between a slow heart rate and the onset of symptoms. These devices include:

  • Holter monitor. This portable ECG device is carried in your pocket or worn on a belt or shoulder strap. It can record 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 recorder. This portable ECG device is intended to monitor your heart activity over a few weeks to a few months. You activate it only when you experience symptoms that may be related to a slow heart rate. When you feel symptoms, you push a button, and an ECG strip of the preceding few minutes and following few minutes is recorded. This permits your doctor to determine your heart rhythm at the time of your symptoms.

Your doctor may also use an ECG monitor while performing other tests to understand the impact of bradycardia. These tests include:

  • Tilt table test. This test helps your doctor better understand how your bradycardia contributes to fainting spells. You lie flat on a special table, and then the table is tilted as if you were standing up. Changes in the position may cause a fainting spell and help your doctor to establish a link between your heart rate and fainting episodes.
  • Exercise test. Your doctor may monitor your heart rate while you walk on a treadmill or ride a stationary bike to see whether your heart rate increases appropriately in response to physical activity.

Laboratory and other tests

Your doctor will order blood tests to screen for underlying conditions that may be contributing to bradycardia, such as an infection, hypothyroidism or an electrolyte imbalance. If sleep apnea is suspected of contributing to bradycardia, you may undergo tests to monitor your sleep.

May. 26, 2011