Sick sinus syndrome

Background

Also known as sinus dysfunction, sinoatrial node disease, and tachycardia-bradycardia syndrome (a specific variant)
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 (i.e. tachycardia-bradycardia syndrome)

Intrinsic:
- Degenerative fibrosis
- Infiltrative disease process (e.g. amyloidosis)
- Ion channel dysfunction
- SA node remodeling
- Myocardial ischemia
Extrinsic:
- Pharmacologic
- Metabolic/electrolyte disturbance
- Autonomic dysfunction
- Obstructive sleep apnea

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
  - Myxedema coma
- Hypoglycemia (neonates)
Toxicologic
Infectious/Postinfectious
Other
- Brash syndrome

ECG identification, inpatient telemetry, outpatient Holter monitoring, event monitoring, loop monitoring
- ECG frequently negative for findings early in disease course

Remove extrinsic factors and/or pacemakers
- Pacemakers do not reduce mortality, only decrease symptoms
Consider reversible causes e.g. treat hyperkalemia or hypokalemia
Atropine for bradycardia, progress to catecholamine or pacing
consider aminophylline, which inhibits suppressive effects of adenosine on the SA node in: [2]
- Acute inferior MI with 2nd or 3rd degree AV block; 250mv IV bolus
- Heart transplant: 6mg/kg in 100-200mL of IV fluid over 20-30 minutes
- Spinal cord injury: 6mg/kg in 100-200mL of IV fluid over 20-30 minutes

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
Kusumoto FM, et al. 2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol. 2019 Aug 20;74(7):e51-e156

This article is issued from Wikem. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.