ECG rhythm strip interpretation worksheet with answers

Free printable ECG rhythm strip interpretation worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
II25 mm/s · 10 mm/mV

This 6-second lead II strip is irregular, so the 300 and 1500 methods do not work. Use the 6-second method to estimate the ventricular heart rate in beats per minute.

lead II, 25 mm/s, 10 mm/mVstrip length 6 s (marks at 0, 3 and 6 s)
heart rate = bpm
2.Easy
II25 mm/s · 10 mm/mV

Measure the PR interval on this lead II strip, in seconds.

lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
PR = s
3.Medium
II25 mm/s · 10 mm/mVsupraventricular tachycardia (SVT)accelerated junctional rhythmventricular tachycardiaatrial flutter, 2:1 conduction

Interpret this lead II rhythm strip. Which rhythm is it? Click your answer.

lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
  1. 1supraventricular tachycardia (SVT)
  2. 2accelerated junctional rhythm
  3. 3ventricular tachycardia
  4. 4atrial flutter, 2:1 conduction
4.Medium
II25 mm/s · 10 mm/mV

Measure the QT interval and the R–R interval on this regular lead II strip, then calculate the rate-corrected QTc with Fridericia’s formula QTc = QT/∛RR (both in seconds). Give the answer in seconds to three decimals.

lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
QTc = s
5.Hard
II25 mm/s · 10 mm/mVtorsades de pointessupraventricular tachycardia (SVT)sinus tachycardiaventricular tachycardia

Identify the rhythm on this lead II strip. Click your answer.

lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
  1. 1torsades de pointes
  2. 2supraventricular tachycardia (SVT)
  3. 3sinus tachycardia
  4. 4ventricular tachycardia
6.Hard
II25 mm/s · 10 mm/mVsecond-degree AV block type IIthird-degree (complete) AV blockfirst-degree AV blocksinus bradycardia

This lead II strip shows a conduction problem between the atria and the ventricles. Which rhythm is it? Click your answer.

lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
  1. 1second-degree AV block type II
  2. 2third-degree (complete) AV block
  3. 3first-degree AV block
  4. 4sinus bradycardia

Answer key

  1. 1. heart rate = 80 bpm
  2. 2. PR = 0.2 s
  3. 3. supraventricular tachycardia (SVT)
  4. 4. QTc = 0.481 s
  5. 5. ventricular tachycardia
  6. 6. second-degree AV block type II

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