What is a sinus arrhythmia?

By Keyur Mavani, MD, Fellow of the American College of Cardiology, FACP Aug 11, 2023 • 4 min

Arrhythmias are abnormalities in the heart’s rhythm. Most types of arrhythmia require treatment to support heart health. However, a sinus arrhythmia is an exception.

What is sinus rhythm?

To understand what sinus arrhythmia is, you first need to know a bit about healthy heart rhythms. In your heart, the sinus node generates electrical impulses that make your heart muscles contract. These impulses also make your heart beat.

The term “sinus rhythm” refers to the rhythm of the heartbeat. When healthcare providers say someone has a normal sinus rhythm, this means that all of the characteristics of their heart rhythm are within normal range.

What is sinus arrhythmia?

As the name suggests, sinus arrhythmia is an irregular heart rhythm that starts in the sinus node responsible for the sinus rhythm. In most people with sinus arrhythmia, the amount of time between heartbeats varies, depending on whether they’re inhaling or exhaling. Generally, heart rate increases when drawing air into the lungs. It then slows down when air travels out of the lungs.

Sinus arrhythmia can occur in people of any age. However, it’s most common in children, adolescents and young adults. In younger people, sinus arrhythmia is rarely a cause for concern, and it can actually be an indicator of a healthy heart.

Less frequently, sinus arrhythmia is unrelated to breathing. It can occur following a head or neck injury. It can also occur due to heart disease or when medication for heart rhythm disorders is taken incorrectly.

What causes sinus arrhythmia?

Researchers have yet to fully understand why some young people develop sinus arrhythmia. However, the vagal nerves of the parasympathetic nervous system seem to play a role. These nerves help control involuntary bodily processes, including heart rate. In people with sinus arrhythmia, breathing may stimulate this nerve, leading to irregularities in heart rhythm.

What are the symptoms of sinus arrhythmia?

In most cases, sinus arrhythmia doesn’t cause any symptoms. However, you may detect the abnormal heart rhythm if you take your pulse rate and observe differences while you inhale and exhale.

People who have non-respiratory sinus arrhythmia, the type of arrhythmia that is unrelated to breathing, may have symptoms due to an underlying condition causing the abnormal heart rhythm. For example, someone with heart disease may also experience chest pain or shortness of breath.

Does sinus arrhythmia require treatment?

When breathing-related sinus arrhythmia occurs in young people, treatment is usually not necessary. Healthcare providers will typically recommend treatments when an underlying condition is the cause of the abnormal heart rhythm.

If you or your child has been diagnosed with sinus arrhythmia, talk to your healthcare provider about whether any additional testing or treatment is necessary.

Updated August 2023.

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