What are the causes of sinus bradycardia?

Updated: Dec 27, 2017
  • Author: Mark W Livingston, MD; Chief Editor: Erik D Schraga, MD  more...
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Causes of sinus bradycardia include the following:

  • One of the most common pathologic causes of symptomatic sinus bradycardia is the sick sinus syndrome.

  • The most common medications responsible include therapeutic and supratherapeutic doses of digitalis glycosidesbeta-blockers, and calcium channel-blocking agents.

  • Other cardiac drugs less commonly implicated include class I antiarrhythmic agents and amiodarone.

  • A broad variety of other drugs and toxins have been reported to cause bradycardia, including lithium, paclitaxel, toluene, dimethyl sulfoxide (DMSO), topical ophthalmic acetylcholine, fentanyl, alfentanil, sufentanil, reserpine, and clonidine.

  • Sinus bradycardia may be seen in hypothermiahypoglycemia, and sleep apnea.

  • Less commonly, the sinus node may be affected as a result of diphtheria, rheumatic fever, or viral myocarditis.

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