From the Guidelines
Bradycardia should be treated with atropine 0.5 to 1 mg IV repeated every 3 to 5 minutes as needed up to 1.5 to 3 mg total, as it is the first-line drug for acute symptomatic bradycardia, according to the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1. This recommendation is based on the strongest and most recent evidence available, which prioritizes morbidity, mortality, and quality of life as the outcome.
Key Points to Consider
- Atropine is the first-line treatment for symptomatic bradycardia, with a recommended dose of 0.5 to 1 mg IV repeated every 3 to 5 minutes as needed up to 1.5 to 3 mg total 1.
- If atropine is not effective, second-line drug therapy with dopamine or epinephrine may be considered, tailored according to potential causes in individual patients 1.
- Transcutaneous pacing may be considered when full-dose atropine fails, although it may not be any more effective than second-line drug therapy 1.
- Theophylline may be administered for the treatment of bradycardia unresponsive to atropine after inferior myocardial infarction, cardiac transplant, or spinal cord injury 1.
Important Considerations
- Atropine should be used with caution in patients with bradycardia after heart transplant, as it may cause paradoxical AV block 1.
- Doses of atropine sulfate of <0.5 mg may paradoxically result in further slowing of the heart rate 1.
- Atropine administration should not delay implementation of external pacing for patients with poor perfusion 1.
From the FDA Drug Label
Atropine-induced parasympathetic inhibition may be preceded by a transient phase of stimulation, especially on the heart where small doses first slow the rate before characteristic tachycardia develops due to paralysis of vagal control Adequate doses of atropine abolish 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 is used to treat bradycardia. It works by inhibiting the muscarinic actions of acetylcholine on the heart, which can help to increase heart rate.
- Key effects: Atropine can abolish reflex vagal cardiac slowing, prevent or abolish bradycardia, and increase heart rate in some patients.
- Important consideration: Atropine may cause a transient phase of stimulation, especially on the heart, before characteristic tachycardia develops due to paralysis of vagal control 2
From the Research
Definition and Causes of Bradycardia
- Bradycardia is a condition characterized by a heart rate of ≤50 beats/minute 3
- It can be caused by various factors, including reversible and irreversible causes
- Reversible causes of bradycardia include medication toxicity and hyperkalemia, which occurred in 4.2% and 8.5% of patients, respectively 3
- Irreversible causes of bradycardia include heart block and atrial arrhythmias with slow ventricular response, which occurred in 38.6% and 46.1% of patients, respectively 3
Management Strategies for Bradycardia
- Various management strategies for symptomatic bradycardia include observation, non-invasive management, early permanent pacemaker (PPM) implantation, and delayed PPM implantation 3
- A study compared these management strategies and found that adverse events were similar in patients who underwent early compared to delayed PPM implantation (6.6% vs 12.5%, P=.20) 3
- However, adverse events were higher in patients who received temporary transvenous pacing (19.1% vs 3.4%, P<.001) 3
Impact of Weekend Admissions on Bradycardia Management
- Weekend admissions were associated with increased temporary transvenous pacing, prolonged median time to PPM implantation by 1 day, and prolonged median length of stay by 2 days 3
- The study suggests that weekend PPM implantation should be considered to reduce temporary transvenous pacing and shorten length of stay 3