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/mVregularregularly irregularirregularly irregular

Look at the R–R intervals on this lead II strip. How would you describe the ventricular rhythm? 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. 1regular
  2. 2regularly irregular
  3. 3irregularly irregular
3.Medium
II25 mm/s · 10 mm/mVatrial flutter, 4:1 conductionjunctional rhythmatrial fibrillationatrial 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. 1atrial flutter, 4:1 conduction
  2. 2junctional rhythm
  3. 3atrial fibrillation
  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 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
5.Hard
II25 mm/s · 10 mm/mVpaced rhythm, failure to capturethird-degree (complete) AV blockidioventricular rhythmsecond-degree AV block type II

This patient has a pacemaker. Interpret the 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. 1paced rhythm, failure to capture
  2. 2third-degree (complete) AV block
  3. 3idioventricular rhythm
  4. 4second-degree AV block type II
6.Hard
II25 mm/s · 10 mm/mVthird-degree (complete) AV blockfirst-degree AV block2:1 AV block (type undetermined)second-degree AV block type II

Interpret this lead II strip. Which interpretation can you defend from this single 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. 2first-degree AV block
  3. 32:1 AV block (type undetermined)
  4. 4second-degree AV block type II

Answer key

  1. 1. PR = 0.16 s
  2. 2. regular
  3. 3. atrial fibrillation
  4. 4. QTc = 0.449 s
  5. 5. paced rhythm, failure to capture
  6. 6. 2:1 AV block (type undetermined)

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