Sick Sinus Syndrome usually occurs in people over 50, often from scar-like damage to the heart's conductive system.
The conduction system is a group of specialized cardiac muscle cells in the walls of the heart that send signals to the heart muscle causing it to contract.

It's often made worse by medications such as digitalis (treats certain heart rhythm problems) , calcium channel blockers, beta-blockers, and anti-arrhythmics.

In children, it's caused by heart surgery, especially to the upper chambers.

SSS is uncommon.
Sinus bradycardia occurs more often than the other types.

Causes