Clinical presentation

Effects of chronic digoxin accumulation include:

• cardiovascular effects
  • minor or early electrocardiographic changes—ST depression with the characteristic ‘reverse tick’ appearance, ectopic beats, first-degree atrioventricular (AV) nodal block
  • bradyarrhythmias—slow atrial fibrillation, second- and third-degree AV block
  • junctional and atrial tachycardia
  • hypotension, syncope
  • ventricular tachycardia, cardiac arrest (ventricular fibrillation, asystole)
• gastrointestinal effects—nausea, vomiting, abdominal pain, diarrhoea
• central nervous system effects—weakness, confusion, delirium, visual disturbance (uncommon)
• metabolic effects—severe digoxin poisoning causes hyperkalaemia with associated electrocardiographic changes; pre-existing hypokalaemia and hypomagnesaemia can exacerbate digoxin toxicity.