Overview

Sick sinus syndrome is the inability of the heart's natural pacemaker (sinus node) to create a heart rate that's appropriate for the body's needs. It causes irregular heart rhythms (arrhythmias). Sick sinus syndrome is also known as sinus node dysfunction or sinus node disease.

The sinus node is an area of specialized cells in the upper right chamber of the heart. This area controls your heartbeat. Normally, the sinus node creates a steady pace of electrical impulses. The pace changes depending on your activity, emotions, rest and other factors.

In sick sinus syndrome, the electrical signals are abnormally paced. Your heartbeat can be too fast, too slow, interrupted by long pauses — or an alternating combination of these rhythm problems. Sick sinus syndrome is relatively uncommon, but the risk of developing it increases with age.

Many people with sick sinus syndrome eventually need a pacemaker to keep the heart in a regular rhythm.