There are several types of slow heart rates (bradycardias or bradyarrhythmias). Each type carries a specific risk of complications and treatment options. Some of the types are described here.
When a person has sinus bradycardia, the heart rate is less than 60 beats per minute. This slow heart rate might be normal. This type of slow heart rate is often seen in healthy, athletic people.
Risk of complications? This type is not likely to cause complications, unless the heart rate is very slow (less than 40 beats per minute).
Treatment. It rarely requires treatment unless it causes symptoms. Then, a pacemaker may be implanted if there is no cause that can be easily treated.
Sinus pause (also called sinus arrest)
During a sinus pause, the heart may miss one or more beats because its natural pacemaker fails to activate the electrical system throughout the rest of the heart.
Risk of complications? Yes, depending on the cause.
Treatment. If this occurs often or over an extended period of time, a person may have symptoms now and then and need a pacemaker. If there is an cause that is identified, that condition may be treated first.
Sick sinus syndrome
Sick sinus syndrome happens when the normal pacemaker of the heart (the sinus node) does not work properly. Various irregular heart rates (arrhythmias) or combinations of arrhythmias can happen. People with this syndrome can have slow arrhythmias or a combination of fast and slow arrhythmias.
For more information, see Sick Sinus Syndrome.
In tachy-brady syndrome, also called tachycardia-bradycardia syndrome, the heart sometimes beats too quickly (tachy) and sometimes beats too slowly (brady). This abnormal heart rhythm problem is often seen in people who have been diagnosed with atrial fibrillation. It can occur when the heart's natural pacemaker is damaged.
Risk of complications? Yes. You may have symptoms such as palpitations and lightheadedness. You might pass out. You might have a higher risk of stroke.
Treatment. Treatment may include a pacemaker to prevent the heart from beating too slowly. Medicines might be used to prevent the heart from beating too fast. Blood-thinning medicines might be used to help prevent a stroke.
Heart block refers to an abnormality in the way electricity passes through the normal electrical pathways of the heart. The abnormality "blocks" the electrical impulse from continuing through the normal pathways and usually results in a slower heart rate.
For more information, see Heart Block.