What is the role of Atropine (antimuscarinic agent) in treating asystole (flatline, cardiac arrest)?

From the Guidelines

Atropine is not recommended for systole (asystole) in cardiac arrest. The available evidence suggests that routine use of atropine during PEA or asystole is unlikely to have a therapeutic benefit [ 1 ]. Instead, the focus should be on high-quality CPR and identifying and treating reversible causes of cardiac arrest. Atropine works by blocking parasympathetic (vagal) influences on the heart, which increases heart rate, but in asystole, the problem isn't excessive vagal tone but rather complete electrical failure of the heart, which atropine cannot overcome.

Key Points to Consider

• The 2015 American Heart Association guidelines update for cardiopulmonary resuscitation and emergency cardiovascular care do not support the routine use of atropine in asystole [ 1 ].
• High-quality CPR, epinephrine administration, and identifying and treating reversible causes of cardiac arrest are the mainstays of treatment for asystole.
• Atropine may still be considered in documented bradycardic arrest due to high vagal tone or primary AV block, but this is not a first-line treatment for asystole [ 1 ].

Clinical Implications

• Healthcare providers should prioritize effective chest compressions, early defibrillation when indicated, and epinephrine administration in the management of cardiac arrest.
• The use of atropine in asystole should be avoided due to the lack of therapeutic benefit and potential for harm [ 1 ].

From the FDA Drug Label

Atropine Sulfate Injection, USP, is indicated for temporary blockade of severe or life threatening muscarinic effects, e.g., as an antisialagogue, an antivagal agent, an antidote for organophosphorus or muscarinic mushroom poisoning, and to treat bradyasystolic cardiac arrest. Adequate doses of atropine abolish various types of reflex vagal cardiac slowing or asystole

Atropine can be used to treat systolic cardiac arrest, specifically bradyasystolic cardiac arrest. The drug works by antagonizing the muscarinic actions of acetylcholine, which can help to abolish reflex vagal cardiac slowing or asystole. Key points to consider:

• Indication: Atropine is indicated for temporary blockade of severe or life-threatening muscarinic effects, including bradyasystolic cardiac arrest.
• Mechanism of action: Atropine antagonizes the muscarinic actions of acetylcholine, which can help to abolish reflex vagal cardiac slowing or asystole.
• Clinical use: Atropine can be used to treat bradyasystolic cardiac arrest, but its effectiveness depends on the underlying cause of the arrest 2.

From the Research

Atropine for Systole

• The use of atropine for systole, specifically in the context of cardiac arrest, has been studied in various research papers 3, 4, 5.
• According to a study published in the Circulation journal, atropine sulfate was assessed in 7,448 adults with non-shockable rhythm, including asystole and pulseless electrical activity (PEA) 3.
• The study found that the epinephrine with atropine group had a significantly higher return of spontaneous circulation (ROSC) rate than the epinephrine alone group in patients with asystole, but there was no long-term neurological benefit 3.
• Another study published in Resuscitation found that atropine had no significant effect on the outcome of patients with PEA, and its use was not recommended for adults with PEA 3.
• A review article published in Critical care nursing clinics of North America discussed the importance of understanding nonshockable rhythms, including PEA and asystole, in in-hospital cardiac arrests, but did not specifically address the use of atropine 4.
• Other studies have focused on the effects of epinephrine in cardiac arrest, including its use in patients with PEA and asystole 6, 7, 5.
• Overall, the evidence suggests that atropine may have some benefits in certain cases of cardiac arrest, but its use is not universally recommended and should be considered on a case-by-case basis 3.