Pathogenesis (disease development)
The most common cause of sick sinus syndrome is idiopathic fibrotic degeneration.
Sick sinus syndrome (SSS) is cardiac arrhythmias due to impaired function of the sinus node (physiologic pacemaker of the heart) caused by various disease states.
The following dysfunctions are grouped under sick sinus syndrome:
- Sinus bradycardia (< 60 heartbeats per minute).
- Intermittent SA block (sinuatrial block), sinus arrest (sinus node arrest).
- Bradycardia-tachycardia syndrome bradycardic phases of the heartbeat (< 60 beats per minute) alternating with tachycardic phases (> 100 beats per minute); this is often associated with an insufficient rate increase under stress (chronotropic incompetence)
Etiology (causes)
Biographical causes
- Age of life – older age
Causes related to disease
- Hypertensive heart disease – heart disease caused by high blood pressure.
- Idiopathic degeneration of the conduction system.
- Cardiomyopathy – weakness of the heart muscle.
- Coronary artery disease – atherosclerosis (arteriosclerosis, hardening of the arteries) in the coronary arteries.
- Myocarditis (inflammation of the heart muscle)
