Management of Symptomatic Bradycardia

First-Line Management

The American College of Cardiology recommends atropine as the first-line pharmacological treatment for symptomatic bradycardia, administered at 0.5-1 mg IV every 3-5 minutes to a maximum total dose of 3 mg, as it works by blocking muscarinic acetylcholine receptors, facilitating sinoatrial conduction and increasing sinus node automaticity 3, 4
Atropine doses less than 0.5 mg may paradoxically worsen bradycardia due to central vagal stimulation, according to the American College of Cardiology 5

The American College of Cardiology suggests that isoprenaline may be considered as a second-line treatment for symptomatic bradycardia when atropine is ineffective, particularly in patients with second-degree or third-degree atrioventricular block who have a low likelihood of coronary ischemia 1, 2
Standard dosing of isoprenaline is 20-60 mcg IV bolus followed by doses of 10-20 mcg, or infusion of 1-20 mcg/min titrated based on heart rate response, as recommended by the American Heart Association 3

The American College of Cardiology recommends that isoprenaline be used with caution in patients with symptomatic bradycardia who have a low likelihood of coronary ischemia, and that patients be monitored closely for potential development of ischemic chest pain during administration 1, 2, 3
Dopamine (5-20 mcg/kg/min IV) may be considered as an alternative chronotropic agent, according to the American Heart Association 3, 6

The American College of Cardiology suggests that transcutaneous pacing should be initiated if pharmacological therapy fails to improve symptoms, and that transvenous temporary pacing is reasonable for patients with persistent symptomatic bradycardia refractory to medical therapy 1, 2, 4
Epinephrine (2-10 mcg/min IV) can also be used to increase heart rate, as recommended by the American Heart Association 3, 7

For patients with tachy-brady syndrome and symptoms attributable to bradycardia, permanent pacing is reasonable to increase heart rate and reduce symptoms, according to the American Heart Association 8
In heart transplant patients, atropine should not be used to treat sinus bradycardia due to denervation, as recommended by the American Heart Association 3, 7