Sick sinus syndrome

In medicine sick sinus syndrome is "a condition caused by dysfunctions related to the sinoatrial node including impulse generation (cardiac sinus arrest) and impulse conduction (sinoatrial exit block). It is characterized by persistent bradycardia, chronic atrial fibrillation, and failure to resume sinus rhythm following cardioversion. This syndrome can be congenital or acquired, particularly after surgical correction for heart defects."