Sinus rhythm refers to the rhythm of your heart beat, determined by the sinus node of your heart. The sinus node creates an electrical pulse that travels through your heart muscle, causing it to contract, or beat. You can think of the sinus node as a natural pacemaker.

While similar, sinus rhythm is different from heart rate. Your heart rate refers to the number of times your heart beats in a minute. Sinus rhythm, on the other hand, refers to the pattern of your heartbeat.

Keep reading to learn about the different types of sinus rhythms and what they mean

Normal sinus rhythm is defined as the rhythm of a healthy heart. It means the electrical impulse from your sinus node is being properly transmitted.

In adults, normal sinus rhythm usually accompanies a heart rate of 60 to 100 beats per minute. However, normal heart rates vary from person to person. Learn what your ideal heart rate is.

When your heart beats too many or too few times in a minute, it’s called arrhythmia.

Sinus tachycardia

Sinus tachycardia occurs when your sinus node sends too many electrical impulses in a certain amount of time, leading to a faster heart rate. While the electric pulse that’s causing your heart to beat may be normal, the pace of these beats is faster than usual. Someone with a heart rate of over 100 beats per minute is considered to have tachycardia.

You may have tachycardia and not know it, since it doesn’t always cause symptoms. In some cases, sinus tachycardia can increase your risk of serious complications, including heart failure, stroke, or sudden cardiac arrest.

There are many possible causes of sinus tachycardia, including:

Sinus bradycardia

Sinus bradycardia is the opposite of sinus tachycardia and happens when your sinus node doesn’t send enough impulses, resulting in a heart rate of fewer than 60 beats per minute.

Keep in mind that a heart rate below 60 beats per minute can be normal for some people, particularly younger adults and athletes. For others, however, it can be a sign that your heart isn’t distributing enough oxygenated blood to your body.

Like sinus tachycardia, sinus bradycardia can be caused by a number of things, including:

  • damage to your heart due to heart disease
  • issues with your sinus node
  • electric conduction issues in your heart
  • damage to your heart related to aging
  • hypothyroidism

Sick sinus syndrome is an umbrella term for a group of symptoms that indicate a problem with the sinus node. In addition to sinus node arrhythmias, other types of sick sinus syndrome include:

  • Sinus arrest. This causes your sinus node to briefly stop transmitting electric impulses.
  • Sinoatrial block. Electrical impulses move too slowly through your sinus node, leading to a slower-than-normal heart rate.
  • Bradycardia-tachycardia (tachy-brady) syndrome. Your heart beat alternates between fast and slow rhythms.

Sinus rhythm refers to the pace of your heart beat that’s set by the sinus node, your body’s natural pacemaker. A normal sinus rhythm means your heart rate is within a normal range. When your sinus node sends electric impulses too fast or too slow, it leads to sinus arrhythmia, including sinus tachycardia or sinus bradycardia. For some people, sinus arrhythmia isn’t anything to worry about, but for others it can be a sign of an underlying condition.