What is Bradycardia?

Bradycardia is an arrhythmia in which the heart rate is slower than normal. If the heart rate is too slow, not enough blood reaches the brain, and the person can lose consciousness. In adults, a heart rate slower than 60 beats per minute is considered an arrhythmia called bradycardia. Some people normally have slow heart rates, especially people who are very physically fit. For them, a heartbeat slower than 60 beats per minute is not dangerous and doesn’t cause symptoms. But in other people, bradycardia can be due to a serious disease or other condition.

Bradycardia can be caused by heart attack, conditions that harm or change the heart’s electrical system (such as underactive thyroid gland or aging), an imbalance of chemicals or other substances such as potassium in the blood, or even some medicines such as beta blockers.

Bradycardia can also can happen as a result of severe bundle branch block. Bundle branch block is a condition in which the electrical signal traveling down either or both of the bundle branches is delayed or blocked. When this happens, the ventricles don’t contract at exactly the same time, as they should, and the heart has to work harder to pump blood to the body. The cause of bundle branch block is often an existing heart condition.

For an arrhythmia such as bradycardia, a cardiologist or electrophysiologist may implant a pacemaker to regulate your heart rate.