Bradyarrhythmia is a type of heart arrhythmia. It is characterized by an abnormally slow and irregular heart beat. It may be a warning sign of an underlying heart health issue or another serious health problem.
For most people, bradyarrhythmia is when the heart rate is irregular and less than 60 beats per minute (bpm). There are many possible causes of bradyarrhythmia, including problems with the heart’s sinus node, which serves as the heart’s natural pacemaker.
This article explains what bradyarrhythmia means and compares it to similar terms a person might hear from a doctor. It also highlights possible causes and symptoms, offers advice on when to talk with a doctor, lists treatment options, and explains the outlook for people with bradyarrhythmia.
Bradyarrhythmia is when the heartbeat is lower than 60 bpm and has an arrhythmia (irregular beat), too.
A normal heart rate is 60–100 bpm when a person is resting but awake. People with slower than normal heart rates have bradycardia, which means that they have a slow heart rhythm with an underlying cause. Sinus bradycardia is when the heart rate is slow but still in “sinus rhythm,” which is the heart’s normal rhythm.
However, simply having a slow heart rate does not necessarily mean something is wrong. Indeed, in some people, it is a sign of excellent cardiovascular health.
It is not unusual for the heart to drop below 60 bpm during sleep. Some people may also find that their heart rate occasionally dips below 60 bpm when they are awake without noticing any other symptoms.
Both these conditions mean that a person’s heart rate is slower than is typical. Bradyarrhythmia usually signifies an underlying condition, whereas bradycardia can be a normal bodily function during certain times, such as during sleep.
Bradyarrhythmia means slower than usual heart rhythm with arrhythmia. Bradycardia means slow heart rate.
People with bradyarrhythmia may present with a slow heart rate and arrhythmia or various other symptoms, including:
When bradyarrhythmia does cause symptoms, a person may notice:
An AV block is not always dangerous and may not require treatment, but some underlying conditions that caused the AV block could be life threatening.
- being an athlete
- recent heart attack
- recently having heart surgery
- heart infection
- unusually high potassium levels
- certain medications, such as beta-blockers
- Lyme disease
However, a second-degree AV block, type II, can be dangerous. These AV blocks happen when conditions, such as chronic infections, a heart attack, or scarring in the heart, damage the heart’s electrical system. This type of AV block may require treatment or monitoring.
A person with an AV block who experiences the following symptoms will likely require treatment: Symptoms include:
The heart is a complex electrical system. In healthy hearts, the sinus node helps generate electrical impulses that tell the heart when and how to beat.
Many different conditions can cause bradycardia as well as an AV block. These can include:
- Idiopathic bradyarrhythmia: Idiopathic means that there is no readily identifiable cause.
- Sinus bradycardia: This is the most
commoncause of bradycardia that occurs when the heart’s sinus generates a slower than normal heart rate. Sometimes this happens for no reason or because a person is very fit. It may also occur when a person has an infection, a genetic heart defect, an injury from a heart attack, an aging heart’s electrical system, or heart trauma.
- Junctional rhythm: Anything that blocks the sinus node and prevents it from functioning may force the atrioventricular node, which controls the top of the heart, to control the heart rate. This may cause the heart to slow down or arrhythmias.
- Sinus pause: A sinus pause is similar to sinus bradycardia in that it can happen in healthy people. It occurs when the sinus node pauses before generating an electrical impulse to cause the heart to beat. If the pause is very long, it can become life threatening.
- Age: Bradyarrhythmias are more common as a person ages. A slow heart rate may also be
more dangerousin an older adult because it increases the risk of falls.
- Vasovagal response: Stress, trauma, or intense fear can activate the body’s vasovagal system and
causelow blood pressure, a low heart rate, or both. Some people faint or feel warm when it happens. A vasovagal episode is usually short-lived, but frequent episodes can increase the risk of dangerous falls.
Anyone concerned about a slow heart should contact a doctor. They should also contact a doctor if they:
- notice their heart rate suddenly becomes slower than usual
- have other symptoms, such as chest pain, trouble breathing, exercise intolerance, dizziness, or fainting or feeling faint
- are taking medication that may lower the heart rate
In some cases, a doctor might send a person home with a portable arrhythmia monitor. The type of heart monitor a person needs and the length of time they need to wear one varies. For example, a person may require:
- A Holter monitor: A person typically wears this monitor for 1–7 days but may have to use it for up to 14 days.
- An event monitor: A person wears this device for 1–2 months. The machine activates when a person turns it on or when it notices abnormal heart rhythms.
- Mobile cardiac telemetry: This monitors the heart rhythms in real-time, with a technician alerting the doctor if it picks up any abnormal rhythms.
- An implantable monitor (loop recorder): Doctors insert a small electrocardiogram monitor under a person’s skin to monitor their heart rhythm over several years. It is useful when a person does not experience abnormal heart rate events often.
Not all bradycardias require treatment. If there are no other symptoms and a person does not have an underlying heart condition, a slow heart rate can be no cause for concern.
When a person has symptoms or an underlying condition, treatment options involve:
- Treating the underlying cause: For example, a heart attack with a blocked blood vessel or severe infection, such as sepsis, may
temporarily causea slow heart rate. Treating the infection or the blockage should restore the heart to its normal rate.
- Treating the arrhythmia: When damage to the heart’s electrical system causes a dangerously slow heart rate, or when the heart rate is slow enough to undermine health, a doctor may recommend using an implantable device, such as a pacemaker. Implanting this device requires surgery.
A person may also require medication to stimulate their heart rate if they experience a heart attack.
The outlook for bradycardia depends on the cause. In some people, a slow heart rate is harmless and even healthy.
Treating the arrhythmia generally results in a good outlook and few complications.
However, certain types of arrhythmia have a poor prognosis. For example, according to a
A slow heart rate can happen for many reasons, but sometimes, there is no apparent cause. Most doctors are unable to make an accurate diagnosis based on symptoms alone. However, if a person with a slow heart rate presents with other symptoms, it may mean they have a heart health issue.
A person should contact a doctor about treatment options and symptoms.