If you have a heart arrhythmia, it means that your heart beats with an abnormal rhythm. It can either be too fast, too slow, or in a chaotic or unpredictable manner.

There are several types of arrhythmias, and each one is associated with potentially serious health issues. Certain arrhythmias, especially atrial fibrillation, are major risk factors for stroke.

Treatment for a potentially life threatening arrhythmia can include medications, devices to steady your heart’s rhythms, and procedures to address the source of the abnormal rhythm.

The heart’s rhythm of contraction and relaxation is controlled by an electrical system featuring two nodes: the sinoatrial (SA) node at the top of the heart’s upper chambers (atria) and the atrioventricular (AV) node at the top of the two lower chambers (ventricles).

The SA node sends an electrical signal to stimulate the atria to contract, moving blood down to the ventricles. The signal slows for a moment in the AV node, before it stimulates the ventricles to contract and pump blood either to the lungs or the rest of the body.

An arrhythmia is some type of disruption to the steady, synchronized flow of electrical energy through the heart. The problem can be an injury or disease that affects the SA node, known as the heart’s natural pacemaker.

Arrhythmias also can develop if there is some interruption along the pathways the electrical impulses travel. Any change in the electrical pattern can cause the heart to beat faster or slower than normal or beat in an unpredictable manner.

Some common causes of arrhythmias include:

Next, we’ll discuss some of the different types of arrhythmias that are associated with a higher stroke risk.

Atrial fibrillation and flutter

Atrial fibrillation (AFib) is the most common arrhythmia, with over 3 million new cases worldwide in 2017. AFib occurs when the atria quiver or beat chaotically, instead of in their usual synchronized pattern.

Atrial flutter has a very similar mechanism to AFib. While atrial flutter is associated with a lower stroke risk than AFib, it’s actually very common to have both atrial flutter and AFib. People who show signs of atrial flutter are typically treated as if they have AFib, which includes the use of medications such as blood thinners.

Sick sinus syndrome

The term sick sinus syndrome refers to several arrhythmias originating in the SA node. Among them are tachycardia-bradycardia syndrome, in which the heart alternates between beating too quickly and then too slowly.

A 2020 study showed that a higher risk of stroke exists in patients with sinus node disease (sick sinus syndrome) compared to patients with other cardiac diseases.


Bradycardia is a slower-than-normal heart rate. In some cases, bradycardia poses no health concerns, while in others, it is associated with fainting due to insufficient blood flow to the brain. In more severe cases, sudden cardiac arrest is a serious concern.

Junctional bradycardia is a slow heart rhythm that originates in the AV node. A 2016 study found that junctional bradycardia is a potential risk factor for stroke in certain people.

Other types of arrhythmias include:

An arrhythmia changes the way your heart beats. In some cases, the ventricles don’t have time to fill and empty enough blood with each heartbeat. Some arrhythmias, such as AFib, cause the heart to beat with less force.

In both cases, blood flow through the heart is interrupted or stalled. So instead of blood moving quickly through the heart’s chambers, some blood can remain in one of the chambers and form a clot.

When the clot eventually leaves the heart, it can travel through the bloodstream up to the small arteries in the brain, blocking blood flow to brain tissue and causing a stroke.

AFib is the arrhythmia most closely associated with stroke. The Centers for Disease Control and Prevention (CDC) reports that AFib is responsible for about 1 out of every 7 strokes and that strokes triggered by AFib tend to be among the most severe.

While arrhythmias can raise the risk of stroke, it’s also true that a stroke can lead to arrhythmias, according to a 2012 study of over 500 patients. The study found that arrhythmias occurred in about 1 out of 4 patients who experienced stroke. People at greatest risk for developing arrhythmia were those who already had various cardiac risk factors, such as high blood pressure.

To lower your stroke risk if you have an arrhythmia, you can adopt a heart-healthy lifestyle and take medications that help keep your heart in a steady rhythm. This can lower your chances of forming clots that can lead to a stroke. Procedures and implantable devices to keep your heart beating steadily may also be necessary.

Among the keys to preventing a stroke are:

You should also keep your blood pressure in a healthy range, as hypertension (high blood pressure) is one of the leading risk factors for stroke.

In mild cases, you may not notice any symptoms. But for more serious arrhythmias — especially those that last for several minutes at a time — it’s important to recognize the symptoms and know which ones are a sign of a medical emergency.

Some symptoms common to several arrhythmias include:

  • heart palpitations
  • a thudding sensation in your chest
  • fatigue
  • lightheadedness
  • fainting
  • anxiety

Other symptoms may include shortness of breath and chest pain or pressure. If you experience these, consider it a medical emergency and get to an emergency department as soon as you can.

An arrhythmia, or abnormal heart rhythm, can be so mild that it requires no treatment and presents no noticeable symptoms. But because an arrhythmia can interfere with the steady flow of blood in and out of the heart, it can raise your risk of blood clots and stroke.

If you’ve been diagnosed with an arrhythmia, talk with your doctor about any preventive measures you should take to lower your risk of a stroke.