Bradycardia
From IDWiki
Differential Diagnosis
- Sinus node dysfunction
- Medications, including parasympathomimetic drugs (acetylcholine, carbachol, acetylcholinesterase inhibitors), sympatholytic drugs (beta blockers, methyldopa, clonidine), opioids and other sedatives, cimetidine, digoxin, non-DHP CCBs (diltiazem and verapamil), ivabradine, amiodarone and other antiarrhythmic drugs, sofosbuvir and daclatasvir (in patients on amiodarone), lithium, chemotherapies (thalidomide, lenalidomide, paclitaxel), and organophosphates
- Acute myocardial infarction
- Obstructive sleep apnoea
- Exaggerated vagal tone
- Increased intracranial pressure
- Infections, including Lyme disease, Chagas disease, legionellosis, psittacosis, Q fever, typhoid fever, typhus, babesiosis, Malaria chemoprophylaxis, leptospirosis, yellow fever, dengue fever, trichinosis, Rocky Mountain spotted fever
- Miscellaneous causes, including hypothyroidism, anorexia nervosa, hypothermia, severe prolonged hypoxia, long QT syndrome, catecholaminergic polymorphic ventricular tachycardia syndrome
Investigations
- Confirm sinus bradycardia with ECG and exclude heart block
- Vital signs including pulse oximetry
- Review medications and exposure history
- TSH to exclude hypothyroidism
Management
Asymptomatic Patients
- Often only need to be monitored
Symptomatic, Hemodynamically Unstable Patients
- Atropine 0.5 mg IV push q3-5min to maximum total dose of 3 mg
- For atropine-resistant hemodynamically-significant bradycardia:
- Consider temporary cardiac pacing
- Consider infusion of dopamine or epinephrine
- Continuous cardiac telemetry
Symptomatic, Hemodynamically Stable Patients
- Rule out acute coronary syndrome and manage as appropriate
- Investigate for and manage other causes
- Review medications and hold any that may be contributing
- Assess for sinus node dysfunction
