A typical healthy heart has a steady rhythm and a resting heart rate of between 60 and 100 beats per minute (BPM) for most adults.

If you have bradyarrhythmia, your heart beats slower than 60 BPM and does not beat from the sinus node, the natural pacemaker of the heart. As a result, blood flow to the brain and other organs can be reduced, leading to fainting and other potential complications.

There are also a few types of bradyarrhythmias, all of which can be caused by a variety of factors. Symptoms can range from mild to medical emergencies. Once bradyarrhythmia is diagnosed, you can determine a treatment plan that may include an implantable devices and lifestyle changes.

Nearly 5 percent of people aged 65 to 73 have some type of arrhythmia, according to a 2018 study. The most common arrhythmia was found to be atrial fibrillation, followed by bradyarrhythmias.

There are two main types of bradyarrhythmia: sinus node dysfunction and atrioventricular (AV) blocks.

Sinus node dysfunction

The sinus node is a cluster of cells the upper right chamber of the heart (right atria). It acts as the heart’s natural pacemaker and controls the heart’s electrical system to ensure a steady rhythm.

Several disorders that fall under the category of sick sinus syndrome can cause the sinus node to fail, potentially leading to a slower heart rate and an irregular heart rhythm.

AV blocks

The AV node is a group of cells that serve as an electrical relay station between the heart’s upper and lower chambers, controlling your heart rate.

When the electrical signal that controls the heart rate is partially or completely blocked, your heart rate can slow down or your heart can begin to beat in an irregular rhythm. This is known as an AV block or a heart block.

The AV node can become blocked in a few different ways:

  • First degree heart block. The mildest type of heart block, in which electrical impulses move slower than normal from the atria through the AV node to the ventricles.
  • Second degree heart block. Either the impulses slow so much that the heart skips a beat (Type I), or some impulses never get to the ventricles and an arrhythmia develops (Type II).
  • Third degree heart block. The impulses from the atria become completely blocked so that the ventricles beat on their own, resulting in a slower, irregular heartbeat that can jeopardize the heart’s ability to pump enough blood to meet the body’s demands.

Second and third degree heart blocks typically require a pacemaker, an electrically charged device that is implanted under the chest skin to help manage heartbeats.

Heart disease, especially if it leads to a heart attack, is a common cause of AV blocks and sick sinus syndrome. Advancing age and the toll the years can put on the heart’s electrical system are also major contributors.

Some other major risk factors for bradyarrhythmia include:

  • infections or other inflammatory conditions of the heart
  • recovering from heart surgery
  • side effects from medications to treat high blood pressure or other arrhythmias
  • obstructive sleep apnea

It’s also possible to inherit genes that raise your risk of bradyarrhythmia. But a 2016 study suggests there is still much to learn about inherited bradyarrhythmia and other causes of the condition.

Another more recent factor that may be causing bradyarrhythmia in some people is infection of the SARS-CoV-2 coronavirus that leads to COVID-19.

A 2020 study suggests:

  • COVID-19 is a possible trigger for arrhythmias, transient bradycardia, and other cardiac condition.
  • Severe inflammation brought on by COVID-19 may pose a severe threat to people who already have bradycardia.

A different 2020 study suggests that special considerations must be made in managing bradyarrhythmia in people with COVID-19 due to a higher risk of complications in people dealing with both COVID-19 and this heart condition.

Bradyarrhythmia episodes can come and go. In cases of mild and infrequent symptoms, no treatment may be needed.

When symptoms become more noticeable, they include:

  • feeling as though your heart is skipping a beat or is otherwise out of rhythm
  • a heart rate that is consistently slower than 60 BPM
  • lightheadedness
  • dizziness
  • fainting
  • fatigue
  • occasional trouble catching your breath
  • exercise intolerance

While it’s easy to measure your heart rate, diagnosing an arrhythmia requires monitoring. The irregular heart rhythm has to be “captured” by a device, such as an ECG.

Other useful monitors include

  • Holter monitor, a small device that monitors the heart 24 hours a day for a week or more
  • event monitor, which is also worn 24 hours a day but is only turned on when you notice a change in your heart rhythm
  • implantable loop recorder, a device placed in the chest that constantly monitors the heart and sends periodic reports to your doctor’s office (only used when arrhythmia episodes are infrequent) and can stay in for years

Blood tests checking for potassium and other electrolytes involved with the heart’s electrical system may also be ordered.

If an abnormal heart rhythm is detected but your heart rate is normal, you may be diagnosed with another type of arrhythmia. An arrhythmia in which the upper chambers quiver or beat out of synch with the lower chambers, for example, is called atrial fibrillation.

If you have bradyarrhythmia and start to feel lightheaded, lie down to avoid a dangerous fall.

If you feel faint, call 911 or tell someone close to you. Having a home defibrillator may be a good idea if you are at risk for sudden cardiac arrest.

Keep in mind that defibrillation can help pace and treat your bradyarrhythmia, but won’t necessarily resolve this type of arrhythmia or address any underlying conditions.

Medical treatments

When bradyarrhythmia symptoms threaten to cause severe complications, such as sudden cardiac arrest, a pacemaker may be implanted in the chest.

A pacemaker can detect an abnormal heartbeat and send an electrical signal to the heart to try to get it beating normally again. A 2018 report found that about a million pacemakers are implanted annually around the world to treat bradyarrhythmias.

A 2018 review of studies notes that any possible reversible causes of bradyarrhythmia should be addressed before a pacemaker is implanted. This can include medications that could be prescribed at a lower dose or swapped out for a different drug.

Anticholinergic medications can also help treat bradyarrhythmias. These work by blocking a neurotransmitter called acetylcholine and help keep your heartbeat steady.

There are no medications designed to safely treat a slow heart rate. But if you have other conditions, such as high blood pressure, you and a doctor will need to monitor your use of antihypertensive drugs. These can cause a dangerous drop in blood pressure.

How to manage bradyarrhythmia

Living with bradyarrhythmia means more than having a pacemaker.

Following a heart-healthy lifestyle is essential. In some cases, addressing an underlying cause can slow or reverse the progression of the condition or at least make your symptoms less severe.

Some changes you should make when diagnosed with bradyarrhythmia include:

Bradyarrhythmia is relatively common, especially among older adults. Bradyarrhythmia can often be managed with medications, devices like pacemakers that regulate the heart’s pumping action, and lifestyle changes.

Bradyarrhythmia can also happen along with cardiac pauses — this happens when the heart “skips” a beat as it alternates between rhythms and can lead to symptoms like fainting.

Check your heart rate to see if it’s slower than 60 BPM and/or if you feel your heart going out of its usual rhythm. If this is the case, see a doctor soon.