Sick Sinus Syndrome
(SSS; Bradycardia-Tachycardia Syndrome; Sinus Node Dysfunction)
by Maria Borowski, MA
The sinus node is a group of cells in the heart that make the heart beat (contract) in a regular pattern. Sick sinus syndrome is a group of symptoms that suggest the sinus node is not working properly. Sick sinus syndrome can lead to:
Sick sinus syndrome usually worsens over time, though some may never know they have it. However, sick sinus syndrome can eventually lead to major heart health complications.
The sinus node is the pacemaker of the heart. It creates and sends electrical signals that stimulate the heart to contract in a regular pattern. The sinus nodes ability to function may be disrupted by:
Sick sinus syndrome is fairly rare. It occurs most often in elderly people and those who have had damage to the heart tissue. It can rarely occur in infants and children due to congenital abnormalities in the heart.
At first, sick sinus syndrome may not have symptoms or the symptoms may come and go. Since the syndrome can cause a variety of problems, symptoms will be different from person to person.
Some people can feel irregular heart beats as flutters in their chest, very rapid heart beats, or missed beats. If the irregular heart patterns are severe enough to affect blood flow to the body symptoms may include:
These symptoms may be caused by other, less serious health conditions. If you experience any one of them, see your doctor.
Sick sinus syndrome may go undetected for some time if it is not causing symptoms. Your doctor will ask about your symptoms and medical history. A physical exam will be done. To examine the electrical activity of your heart your doctor order one or more of the following test:
For people with no symptoms, treatment may not be needed. Sick sinus syndrome can eventually increase the risk of other cardiovascular issues such as atrial fibrillation, heart failure, heart attack, or stroke. As a result, your doctor will monitor your overall heart health.
Treatment may be needed if the irregular heart patterns are disrupting the flow of blood through the heart. The exact treatment will depend on the individual's needs. Options include the following:
For most people, sick sinus syndrome is not preventable.
American Heart Association
Heart Rhythm Society
Canadian Heart Rhythm Society
Heart and Stroke Foundation of Canada
Semelka M, Gera J, Usman S. Sick sinus syndrome: a review. Am Fam Physician. 2013;87(10):691-696.
Sick sinus syndrome. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T113692/Sick-sinus-syndrome . Updated December 8, 2015. Accessed November 28, 2017.
Sick sinus syndrome. Heart Rhythm Society website. Available at:
...(Click grey area to select URL)
Accessed November 28, 2017.
Sinus node dysfunction. Merck Manual Professional Version website. Available at:
...(Click grey area to select URL)
Updated September 2017. Accessed November 28, 2017.
Last reviewed November 2018 by EBSCO Medical Review Board Michael J. Fucci, DO, FACC
Last Updated: 12/20/2014
EBSCO Information Services is fully accredited by URAC. URAC is an independent, nonprofit health care accrediting organization dedicated to promoting health care quality through accreditation, certification and commendation.
This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.
To send comments or feedback to our Editorial Team regarding the content please email us at firstname.lastname@example.org. Our Health Library Support team will respond to your email request within 2 business days.