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ECG Interpretation Drills for Vignette Exams

A high-yield ECG method designed for PLAB/MLA/MRCP-style questions: rapid rhythm ID, axis, intervals, ischaemia, and exam-grade wording.

Review date
Feb 2026
Reading time
11 min read
Author
Dr. Kola Tytler MBBS CertHE MBA MSt MRCGP
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Key points

  • Most ECG errors are <strong>sequence errors</strong>. Fix the sequence and your accuracy jumps.
  • Use a 60–90 second ECG script that always covers: rate, rhythm, axis, intervals, morphology, and clinical meaning.
  • Train with <strong>micro-drills</strong> (10 ECGs/week) and a structured error log.
Vignette exams rarely reward you for being poetic about ECGs. They reward fast identification of patterns, safe differentials, and correct immediate actions. The easiest win is to adopt a rigid sequence that you never break.

The 90-second ECG script (memorise it)

<strong>1) Rate</strong> (regular vs irregular) <strong>2) Rhythm</strong> (P waves? relationship to QRS?) <strong>3) Axis</strong> (normal/left/right/extreme) <strong>4) Intervals</strong> (PR, QRS, QT/QTc) <strong>5) Morphology</strong> (bundle branch block, hypertrophy) <strong>6) Ischaemia</strong> (ST elevation/depression, T changes) <strong>7) So what?</strong> (what it means + what you do next)
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Step 1 — Rhythm first, always

If rhythm is unclear, stop everything else. Identify: regular vs irregular, narrow vs broad, and whether P waves are present/related. This alone answers many exam questions.
2

Step 2 — Don’t guess QT (estimate properly)

QT mistakes are common. If the vignette is clearly about QT prolongation/torsades risk, slow down and measure. Then consider drivers: electrolytes, drugs, bradycardia.
3

Step 3 — Ischaemia: describe what you see, then interpret

Write/think: “ST elevation in leads X with reciprocal changes in Y.” Then interpret in context. Exams punish vague “ischaemic changes” statements when the pattern is specific.
4

Step 4 — “So what?” is the scoring layer

End with the action logic: “This is AF with RVR → rate control and anticoagulation assessment.” / “This is VT → treat as VT, immediate senior help.” Even if you’re not asked, practising this makes you safer and faster.

Your ECG error log labels (use these)

  • Sequence break (skipped rhythm or intervals).
  • Narrow/broad misclassification.
  • Axis confusion.
  • ST/T overcall (calling ischaemia without pattern).
  • QT miss (didn’t measure when QT was the point).

Do not overfit to rare zebras

For revision: master the common patterns (AF, flutter, SVT, VT, AV block, STEMI/NSTEMI patterns, hyperkalaemia changes). Rare patterns come later. Exams reward reliability under time pressure.
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The 10-per-week drill (sustainable, high yield)

Every week: 10 ECGs. For each: run the 90-second script, then check against an explanation. Capture the error label. After 6 weeks, your mistakes will cluster—and you fix the cluster.
SourceGMC: MLA Content Map (ECG interpretation sits within core safe-practice expectations)
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  • If rhythm is unclear, stop everything else. Identify: regular vs irregular, narrow vs broad, and whether P waves are present/related. This alone answers many exam questions.

    Return to this section

  • QT mistakes are common. If the vignette is clearly about QT prolongation/torsades risk, slow down and measure. Then consider drivers: electrolytes, drugs, bradycardia.

    Return to this section

  • Write/think: “ST elevation in leads X with reciprocal changes in Y.” Then interpret in context. Exams punish vague “ischaemic changes” statements when the pattern is specific.

    Return to this section

  • End with the action logic: “This is AF with RVR → rate control and anticoagulation assessment.” / “This is VT → treat as VT, immediate senior help.” Even if you’re not asked, practising this makes you safer and faster.

    Return to this section
  • Return to this section
  • Return to this section
  • Return to this section
  • Return to this section
  • Return to this section

  • Every week: 10 ECGs. For each: run the 90-second script, then check against an explanation. Capture the error label. After 6 weeks, your mistakes will cluster—and you fix the cluster.

    Return to this section

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