Sick sinus syndrome
Background
- Also known as "Tachy-Brady Syndrome"
- Collection of signs or symptoms that indicate sinus node dysfunction[1]
- May present as bradycardia, tachycardia, or alternating bradycardia and tachycardia
- 50% have alternating bradycardia and tachycardia
Causes
- Intrinsic:
- Degenerative fibrosis
- Infiltrative disease process
- Ion channel dysfunction
- SA node remodeling
- Extrinsic:
- Pharmacologic
- Metabolic/electrolyte disturbance
- Autonomic dysfunction
- Obstructive sleep apnea
Clinical Features
- Syncope or pre-syncope (50%)
- Palpitations
- Fatigue
- Generalized weakness
- Dyspnea
- Angina
- Disturbed sleep
- Confusion
Differential Diagnosis
Symptomatic bradycardia
- Cardiac
- Inferior MI (involving RCA)
- Sick sinus syndrome
- Neurocardiogenic/reflex-mediated
- Increased ICP
- Vasovagal reflex
- Hypersensitive carotid sinus syndrome
- Intra-abdominal hemorrhage (i.e. ruptured ectopic)
- Metabolic/endocrine/environmental
- Hyperkalemia
- Hypothermia (Osborn waves on ECG)
- Hypothyroidism
- Hypoglycemia (neonates)
- Toxicologic
- Infectious/Postinfectious
- Other
Evaluation
- ECG identification, inpatient telemetry, outpatient Holter monitoring, event monitoring, loop monitoring
- ECG frequently negative for findings early in disease course
Management
- remove extrinsic factors and/or pacemakers
- Pacemakers do not reduce mortality, only decrease symptoms
Disposition
- Admit
Complications
- (50%) Tachy-brady syndrome with atrial fibrillation or atrial flutter
- (50%) AV block
See Also
External Links
References
- ↑ Semelka, M et Al. Sick Sinus Syndrome: A Review. Am Fam Physician. 2013 May 15;87(10):691-696. http://www.aafp.org/afp/2013/0515/p691.html