Sinus Bradycardia Clinical Presentation
- Author: Mark W Livingston, MD; Chief Editor: Erik D Schraga, MD more...
Sinus bradycardia is most often asymptomatic. However, symptoms may include the following:
- Chest pain
- Shortness of breath
- Exercise intolerance
Pertinent elements of the history include the following:
- Previous cardiac history (eg, myocardial infarction, congestive heart failure, valvular failure)
- Toxic exposures
- Prior illnesses
Cardiac auscultation and palpation of peripheral pulses reveal a slow, regular heart rate.
The physical examination is generally nonspecific, although it may reveal the following signs:
- Decreased level of consciousness
- Peripheral edema
- Pulmonary vascular congestion
- Poor perfusion
Causes of sinus bradycardia include the following:
- One of the most common pathologic causes of symptomatic sinus bradycardia is the sick sinus syndrome.
- 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.
- Less commonly, the sinus node may be affected as a result of diphtheria, rheumatic fever, or viral myocarditis.
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