Name = Bradycardia
ICD10 = ICD10|R|00|1|r|00
ICD9 = ICD9|427.81, ICD9|659.7, ICD9|785.9, ICD9|779.81
Bradycardia, as applied to adult medicine, is defined as a resting
heart rateof under 60 beats per minute, though it is seldom symptomatic until the rate drops below 50 beat/min. [http://www.emedicine.com/emerg/topic534.htm Sinus Bradycardia] eMedicine] Trained athletes tend to have slow resting heart rates, and resting bradycardia in athletes should not be considered abnormal if the individual has no symptoms associated with it.
The term "relative bradycardia" is used to explain a heart rate that, while not technically below 60 beats per minute, is considered too slow for the individual's current medical condition.
cardiac arrhythmiacan be underlain by several causes, which are best divided into cardiac and non-cardiac causes.Non-cardiac causes are usually secondary, and can involve drug use or abuse; metabolic or endocrineissues, especially in the thyroid; an electrolyteimbalance; factors; autonomic reflexes; situational factors such as prolonged bed rest; and autoimmunity.Cardiac causes include acute or chronic ischemic heart disease, vascular heart disease, valvular heart disease, or degenerative primary electrical disease.Ultimately, the causes act by three mechanisms: depressed automaticity of the heart, conduction block, or escape pacemakers and rhythms.
There are generally two types of problems that result in bradycardias: disorders of the
sinoatrial node(SA node), and disorders of the atrioventricular node(AV node).
With sinus node dysfunction (sometimes called
sick sinus syndrome), there may be disordered automaticityor impaired conduction of the impulse from the sinus node into the surrounding atrial tissue (an "exit block").It is difficult and sometimes impossible to assign a mechanism to any particular bradycardia, but the underlying mechanism is not clinically relevant to treatment, which is the same in both cases of sick sinus syndrome: a permanent pacemaker.
Atrioventricular conduction disturbances (aka: AV block; 1o AV block, 2o type I AV block, 2o type II AV block, 3o AV block) may result from impaired conduction in the AV node, or anywhere below it, such as in the bundle of HIS.
Patients with bradycardia have likely acquired it, as opposed to having it
congenitally.Bradycardia is more common in older patients.
There are 2 main reasons for treating any
cardiac arrhythmias.With bradycardia, the first is to address the associated symptoms, such as fatigue, limitations on how much a person can physically exert, fainting(syncope), dizzinessor lightheadedness, or other vague and non-specific symptoms.The other reason to treat bradycardia is if the person's ultimate outcome (prognosis) will be changed or impacted by the bradycardia.Treatment depends on whether any symptoms are present, and what the underlying cause is.
Drug treatment is not needed if the pt is asymptomatic.
In symptomatic pts, draw a chem 12 and abg's to assess electrolytes and blood gases. IV
atropinemay provide temporary improvement in symptomatic pts.
for symptomatic pts:
Atropine0.5-1 mg IV or ET q3-5min [maximum dose is 3 mg total] (0.04 mg/kg)
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