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 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
2.Easy
II25 mm/s · 10 mm/mV

The rhythm on this lead II strip is regular. Use the 300 method (300 ÷ the number of large boxes between two consecutive R waves) to estimate the heart rate in beats per minute, rounded to a whole number.

lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
heart rate = bpm
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 Bazett’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/mVatrial fibrillationsinus bradycardiajunctional rhythmnormal sinus rhythm

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. 1atrial fibrillation
  2. 2sinus bradycardia
  3. 3junctional rhythm
  4. 4normal sinus rhythm
5.Hard
II25 mm/s · 10 mm/mV

This lead II strip shows second-degree AV block type I (Wenckebach). How many P waves per group are there, counting the non-conducted one (the n of an n:(n − 1) block)?

lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
P waves per group =
6.Hard
II25 mm/s · 10 mm/mVthird-degree (complete) AV blockventricular tachycardiaidioventricular rhythmsinus bradycardia

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. 1third-degree (complete) AV block
  2. 2ventricular tachycardia
  3. 3idioventricular rhythm
  4. 4sinus bradycardia

Answer key

  1. 1. PR = 0.32 s
  2. 2. heart rate = 50 bpm
  3. 3. QTc = 0.46 s
  4. 4. junctional rhythm
  5. 5. P waves per group = 3
  6. 6. idioventricular rhythm

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