All areas of clinical practice · UKMLA & AKT

Drug-induced prolonged QT and arrhythmias

A free high-yield preview for the UKMLA Applied Knowledge Test. Below are the key points to recognise drug-induced prolonged qt and arrhythmias — the full SA Note notes add investigations, management, complications and 10 practice questions.

Key high-yield points

  • Drug-induced QT prolongation occurs when drugs block the hERG (IKr) potassium channel, slowing phase 3 repolarisation. This prolongs the action potential, predisposes to early afterdepolarisations (EADs), and can trigger torsades de pointes (TdP) - a polymorphic VT that may degenerate into VF.
  • QTc calculated using Bazett formula: QTc = QT / √RR
  • Prolonged QTc: >440 ms (males), >460 ms (females); QTc >500 ms = high-risk threshold

Unlock the full Drug-induced prolonged QT and arrhythmias revision

Get the complete high-yield notes (4 more sections covering investigations, management and complications), 10 practice questions, mock exams and AI tutoring. Start free.

Related UKMLA topics

Drug-induced liver injuryDrug-induced nephrotoxicitySerotonin syndromeNeuroleptic malignant syndromeStevens-Johnson syndrome and toxic epidermal necrolysisDrug-induced blood dyscrasias