Sinus Bradycardia

Your heart has a complex electrical system that keeps it beating in rhythm.

Bradycardia is when your heart rate is less than 60 to 100 beats per minute.

Bradycardia is a normal condition in some athletes, and for young people at rest. But sometimes the heart beats too fast or slow. This is called an arrhythmia. To understand how it happens, it helps to know how the heart works.

Your heart has four chambers, two on the top called atria, and two on the bottom called ventricles. These chambers work together to pump your blood. The right atrium and ventricle pump blood to your lungs. The left atrium and ventricle pump blood to the rest of your body.

Electrical signals travel through your heart, causing it to pump about 60 times per minute. Normally, the signals start at the top of your right atrium in an area called the sinoatrial, or S-A, node.

The signals spread across your atria to a spot between the atria and ventricles, called the atrioventricular, or A-V, node.

Then the signals travel down a wall between your ventricles called the septum, and out across your ventricles. Damage to any part of your heart's electrical system can cause arrhythmias.

The S-A node acts as your body's natural pacemaker. It controls your heart rhythm. If your S-A node sends out fewer than sixty signals per minute, you have sinus bradycardia.

This can be due to other heart problems, medications, or high blood pressure. However, it's usually not a sign of any serious problems. It's often a normal effect of aging on the heart's electrical system.

You may not notice any symptoms with sinus bradycardia, but you might get some symptoms such as:

  • Fatigue
  • Weakness
  • Lightheadedness
  • Fainting or near-fainting, and
  • A slow pulse


If you have symptoms, your health care provider will give you a physical exam and ask about your symptoms. He or she will want to know when your symptoms happen, how long you've had them, if you have any other medical problems, and if you're taking medications. If you've been tracking your pulse, be sure to tell your health care provider what you've learned.

You may also have certain tests. An electrocardiogram, or ECG, is used to map your heart's electrical activity. It can show whether your slow heart rate is sinus bradycardia and if there are other problems. If the results aren't clear, you may need to wear a heart monitor that records your heart's activity for a day or two.

You may also have other tests, including:

  • A treadmill, or stress test
  • A tilt table test, or
  • An echocardiogram, or heart ultrasound

Your health care provider might also order heart, urine, or blood tests.


Sinus bradycardia may not need to be treated. If it's a side effect of your medications, your health care provider may change your medication or your dose.

If your bradycardia is caused by a disease in your S-A node, you may need a pacemaker. If it's caused by another type of heart disease, you may need other treatments.

A healthy lifestyle can help keep your heart strong. If you don't exercise, talk to your provider about the best activity level for you, and get active. If you smoke, quit. And, make sure you're eating a healthy diet.

Things to Remember

Bradycardia is a heart rate slower than sixty beats per minute.
Sinus bradycardia can be normal in athletes and during sleep.
You may not have symptoms.
If your bradycardia is due to sinoatrial node disease, you may need a pacemaker.

What We Have Learned

Bradycardia is a heart rate slower than sixty beats per minute. True or false? The answer is true. A normal heart rate is about 60 beats per minute.

The only treatment for bradycardia is a pacemaker. True or false? The answer is false. There are various kinds of treatment that can work for bradycardia. And in some cases, you may not need treatment.