From the Guidelines
Symptomatic bradycardia should be managed with atropine 0.5 mg IV every 3-5 minutes up to a maximum of 3 mg as the first-line treatment, as recommended by the most recent guidelines 1. For immediate management, administer atropine 0.5 mg IV every 3-5 minutes up to a maximum of 3 mg. If atropine is ineffective, use transcutaneous pacing or infusions of epinephrine (2-10 mcg/min) or dopamine (2-10 mcg/kg/min) as second-line treatments. The following symptoms warrant intervention:
- Syncope
- Dizziness
- Fatigue
- Exercise intolerance
- Confusion
- Signs of hypoperfusion The underlying cause should be identified and addressed, including:
- Medication review (beta-blockers, calcium channel blockers)
- Electrolyte abnormalities
- Hypothyroidism
- Structural heart disease Bradycardia becomes clinically significant when the heart rate falls below 60 beats per minute and cardiac output becomes insufficient to meet the body's metabolic demands. While awaiting definitive treatment, position the patient supine with legs elevated, ensure adequate oxygenation, establish IV access, and continuously monitor vital signs and cardiac rhythm, as supported by previous studies 1. For persistent or recurrent symptomatic bradycardia, permanent pacemaker implantation is the definitive treatment, as stated in the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1.
From the FDA Drug Label
Atropine abolishes various types of reflex vagal cardiac slowing or asystole The drug also prevents or abolishes bradycardia or asystole produced by injection of choline esters, anticholinesterase agents or other parasympathomimetic drugs, and cardiac arrest produced by stimulation of the vagus. Atropine also may lessen the degree of partial heart block when vagal activity is an etiologic factor In some patients with complete heart block, the idioventricular rate may be accelerated by atropine; in others, the rate is stabilized.
Atropine is used to treat symptomatic bradycardia by counteracting vagal activity that may be causing the bradycardia.
- Key benefits: Atropine can abolish reflex vagal cardiac slowing, prevent bradycardia, and stabilize the heart rate in some patients with complete heart block.
- Clinical use: Atropine may be used to treat symptomatic bradycardia, particularly when vagal activity is suspected to be the cause 2.
From the Research
Definition and Causes of Symptomatic Bradycardia
- Symptomatic bradycardia is defined as a heart rate lower than 60 beats/min, which can be due to sinus, atrial, or junctional bradycardia or to a problem with the conduction system (eg, an atrioventricular block) 3.
- Bradyarrhythmias can be benign, requiring no treatment; however, acute unstable bradycardia can lead to cardiac arrest 4.
Symptoms of Symptomatic Bradycardia
- Bradycardia symptoms can include syncope, dizziness, chest pain, dyspnea, or fatigue 3.
- It is essential to determine during the evaluation if bradycardia is the cause of the patient's symptoms 3.
Management of Symptomatic Bradycardia
- In the acute setting, symptomatic patients should be treated with atropine 3.
- Percutaneous pacing can be used as a bridge to definitive treatment 3.
- The only therapy for persistent bradycardia is placement of a permanent pacemaker 3.
- Management of bradycardia is based on the severity of symptoms, the underlying causes, presence of potentially reversible causes, presence of adverse signs, and risk of progression to asystole 4.
- Pharmacologic therapy and/or pacing are used to manage unstable or symptomatic bradyarrhythmias 4.
- Symptomatic patients with sick sinus syndrome and high second- or third-degree atrioventricular blocks require placement of permanent pacemakers 3.