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

Measure the QRS duration 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
QRS = s
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/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
4.Medium
II25 mm/s · 10 mm/mV

This lead II strip shows atrial flutter. How many flutter waves per QRS complex are there (the n of n:1 conduction)?

lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
flutter waves per QRS =
5.Hard
II25 mm/s · 10 mm/mVsecond-degree AV block type IIfirst-degree AV blocksecond-degree AV block type I (Wenckebach)third-degree (complete) AV block

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. 2first-degree AV block
  3. 3second-degree AV block type I (Wenckebach)
  4. 4third-degree (complete) AV block
6.Hard
II25 mm/s · 10 mm/mVventricular fibrillationsinus tachycardiaventricular tachycardiaatrial flutter, 2:1 conduction

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. 1ventricular fibrillation
  2. 2sinus tachycardia
  3. 3ventricular tachycardia
  4. 4atrial flutter, 2:1 conduction

Answer key

  1. 1. QRS = 0.06 s
  2. 2. PR = 0.16 s
  3. 3. QTc = 0.491 s
  4. 4. flutter waves per QRS = 2
  5. 5. second-degree AV block type II
  6. 6. ventricular tachycardia

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