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

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
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/mVsinus arrhythmiafirst-degree AV blocksinus bradycardianormal 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. 1sinus arrhythmia
  2. 2first-degree AV block
  3. 3sinus bradycardia
  4. 4normal sinus rhythm
5.Hard
II25 mm/s · 10 mm/mV

This lead II strip shows an AV block with an irregular ventricular rhythm. Use the 6-second method to find the ventricular rate in beats per minute.

lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
ventricular rate = bpm
6.Hard
II25 mm/s · 10 mm/mVjunctional rhythmthird-degree (complete) AV blockdual-chamber (AV) paced rhythmsinus rhythm with wide QRS

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. 1junctional rhythm
  2. 2third-degree (complete) AV block
  3. 3dual-chamber (AV) paced rhythm
  4. 4sinus rhythm with wide QRS

Answer key

  1. 1. QRS = 0.08 s
  2. 2. heart rate = 80 bpm
  3. 3. QTc = 0.44 s
  4. 4. normal sinus rhythm
  5. 5. ventricular rate = 50 bpm
  6. 6. dual-chamber (AV) paced rhythm

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