Overview
- Bradycardia refers to heart rate <60/min in an adult
- Bradycardias are classified as regular or irregular, narrow complex or wide complex
Differential diagnosis causing bradycardia
- Cardiac disease
- Myocardial ischaemia / infarction
- Myocarditis
- Cardiomyopathies
- Hypoxia
- Electrolyte disturbance – Hyperkalemia
- Medications, poisonings and toxic exposures
- Digoxin
- Beta blockers
- Calcium channel blockers
- Amiodarone
- Clonidine
- Hypothermia
- Hypothyroidism
- Raised intracranial pressure (Cushing response)
- Infections (Lyme disease, diphtheria, typhoid fever)
- Autoimmune – Systemic lupus erythematosis
- Infiltrative disorders (e.g. sarcoidosis, amyloidosis)
- Physiological causes
- athletes
- vagal response
| Remember Life threatening causes of bradycardia include: hypotension, raised intracranial pressure and MI. |
History
- Past medical history
- Cardiac history and risk
- Medical conditions – screen for
- Hypothyroidism
- Autoimmune/ infiltrative disease
- Medication – digoxin, beta-blocker, calcium channel blockers or other antiarythmics
Examination
- General observation
- Vitals
- Low body temperature?
- Cushings triad
- ECG
- Hyperkalaemia – Tall tented T-waves
- Cardiovascular examination
- Respiratory examination
Acute Management
- ABCD
- Oxygen
- IV access
- Tredenleberg position if hypotensive
- ECG
- Drug: Atropine
- Transthoracic pacing
- Low dose adrenaline infusion – if transthoracic pacing unavailable
- CPR – if deteriorating
| Pharmacology Atropine |
Investigations
- FBC
- EUC
- Hyperkalaemia
- LFT
- CRP
- Cardiac biomarkers
- Cardiac ultrasound
Discussion