Sick sinus syndrome overview

Overview

Sick sinus syndrome is a group of abnormal heart rhythms (arrhythmias) caused by a malfunction of the sinus node, the heart's "natural" pacemaker. It encompasses disorder causing reduced automaticity of the sinoatrial node, exit block, and sinus arrest. The syndrome primarily affects the elderly, and is associated with paroxysmal atrial fibrillation or flutter in approximately half of the patients and with distal conduction disease in up to one tenth of patients. It is also sometimes called as tachycardia-bradycardia syndrome and is characterized by periods of bradycardia alternating with periods of atrial fibrillation with rapid ventricular response. Management of the syndrome usually requires an implanted permanent pacemaker.