6th March 2024

Background

Bradycardia is defined as a ventricular rate below 60 bpm and may be physiological in athletes or during sleep. Pathological bradycardia may be a consequence of SA node and or AV node dysfunction. In these cases, patients may present with fatigue, dizziness, syncope, vertigo, and hypotension. Causes for bradycardia include:

• Acute myocardial infarction and ischaemia
• Disease of SA node (Sick sinus syndrome)  
• AV node dysfunction
• Anorexia nervosa
• Hypothyroidism 
• Hypothermia 
• Electrolyte imbalances – hypo or hyperkalaemia.
• Raised intracranial pressure
• Increased vagal tone 
• Medications: beta blockers, digoxin, calcium channel blockers, ivabradine, lithium, clonidine.