Atropine Therapy in Cardiovascular and Toxicological Emergencies

Primary Cardiovascular Indications

The American College of Cardiology recommends atropine for symptomatic bradycardia with hemodynamic compromise, defined as heart rate <50 bpm with hypotension, low cardiac output, peripheral hypoperfusion, or frequent premature ventricular contractions 1, 2
Atropine is indicated for bradycardia and hypotension following nitroglycerin administration, with a recommended dose of 0.5 mg IV every 5 minutes, maximum total dose 2 mg 1, 3
The American College of Cardiology suggests that atropine is most effective when used within 6 hours of acute MI onset, particularly with inferior MI or right coronary artery involvement 2

The American College of Cardiology recommends atropine for symptomatic Type I (Mobitz I) second-degree AV block at the AV nodal level, especially with acute inferior MI 1, 2
Atropine is indicated for third-degree AV block at the AV node level with narrow-complex escape rhythm, with a recommended dose of 0.5 mg IV every 5 minutes, maximum total dose 2 mg 2
The American College of Cardiology recommends atropine for ventricular asystole, with a dose of 1 mg IV, repeated every 3-5 minutes if asystole persists during CPR 1

The American College of Cardiology suggests atropine as an antisialagogue for nausea and vomiting associated with morphine administration in acute MI, with a recommended initial dose of 0.5-1 mg IV 1, 3, 4
Atropine is contraindicated for asymptomatic sinus bradycardia >40 bpm without hypoperfusion or ventricular ectopy, and for Type II second-degree AV block or infranodal third-degree block (wide QRS) 1, 2, 3, 4

The American College of Cardiology recommends a standard dosing of 0.5 mg IV every 5 minutes, maximum total dose 2 mg, for bradycardia, and warns against using doses <0.5 mg IV, which can cause paradoxical bradycardia 1, 3, 5
The American College of Cardiology suggests that cumulative doses >2.5 mg over 2.5 hours increase the risk of ventricular tachycardia/fibrillation, CNS toxicity, and sustained sinus tachycardia 1

The American College of Cardiology warns against giving atropine for wide-complex bradycardia or high-grade AV block with bundle branch block, as this represents infranodal disease requiring pacing, not atropine 1, 2
The American College of Cardiology recommends confirming asystole in two ECG leads before treating, as fine ventricular fibrillation may appear as asystole 6
The American College of Cardiology suggests that if bradycardia doesn't respond promptly to atropine, one should proceed immediately to transcutaneous or transvenous pacing rather than continuing to escalate atropine doses 1, 2