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Bradycardia is a slow heart rate, when the heart beats less than 60 beats per minute. In some patients, who are otherwise healthy, the heartbeat may slow to less than 60 beats per minute while resting or sleeping. This usually causes no symptoms and does not require treatment. In other patients, bradycardia may occur due to age-related wear and tear on the heart or some other heart disease and may cause undue fatigue, lightheadedness, or fainting (syncope).
There are two basic types of bradycardia:
- Sick sinus syndrome occurs when the sinus node (the heart's own pacemaker) fails and does not reliably trigger heartbeats. This is very common in elderly persons, but may occur at any age.
- Heart block is a complete or partial interruption of the electrical impulses on their way to the ventricles and results in a slow, unreliable heartbeat. Heart block may be present at birth, may result from other types of heart disease (after a heart attack for example), or may be due to age-related wear and tear on the heart's electrical system.
Permanent pacemakers can be implanted to prevent patients from experiencing symptoms due to a slow heart beat.