A doctor can sometimes diagnose bradycardia by:

• Asking questions about your medical history.
• Doing a physical exam.
• Using an electrocardiogram (EKG, ECG).

An EKG also helps determine what type of slow heart rate you have. This noninvasive test can also provide information about contributing factors, such as a recent heart attack or other underlying heart conditions.

If your bradycardia comes and goes and is not recorded during the EKG that is done during your office visit, you may need ambulatory heart monitoring (Holter or cardiac event monitoring). This type of monitoring uses a portable EKG machine to record the electrical activity of your heart while you go about your daily routine.

To see if there are other conditions that may be causing your slow heart rate, you may have lab tests, such as a:

• Thyroid function, to check for hypothyroidism.
• Chemistry screen, to check for electrolyte imbalances.

If you take a cardiac medicine called digoxin, you may have blood tests to see whether high levels of digoxin could be causing bradycardia.

If the cause of your symptoms is still not clear, you may need other testing. This may include:

• Ambulatory heart monitoring, such as Holter or cardiac event monitoring.
• Exercise testing. This test uses EKG to record your heart's electrical activity during exercise.
• Tilt table testing.
• Electrophysiologic testing.