Sinus Bradycardia
Definition

Sinus rhythm with a resting heart rate of < 60 bpm in adults, or below the normal range for age in children. Normal heart rates in children Newborn: 110 – 150 bpm 2 years: 85 – 125 bpm 4 years: 75 – 115 bpm 6 years+: 60 – 100 bpm Causes Non-pharmacological Normal during sleep Increased vagal tone (e.g. athletes) Vagal stimulation (e.g. pain) Inferior myocardial infarction Sinus node disease Hypothyroidism Hypothermia Anorexia nervosa Electrolyte abnormalities – hyperkalaemia, hypermagnesaemia Brainstem herniation (the Cushing reflex) Myocarditis. Pharmacological Beta-blockers Calcium-channel blockers (verapamil & diltiazem) Digoxin Central alpha-2 agonists (clonidine & dexmedetomidine) Amiodarone Opiates GABA-ergic agents (barbiturates, benzodiazepines, baclofen, GHB) Organophosphate poisoning