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Certified Medical Assistant — Practice Exam

Electrocardiography: practice questions

Our Medical Assistant bank has 20 questions on this topic. Here are 5 of them with answers; the full mock exam draws from every topic, like the real one.

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Question 1

What should a patient avoid while wearing a Holter monitor?

  1. Writing in the symptom diary
  2. Bathing or getting the device wet
  3. Sleeping in their own bed at night
  4. Walking or doing normal daily tasks
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B. Bathing or getting the device wet — Normal activity is encouraged so symptoms can be captured.

Question 2

What does the P wave represent on an ECG?

  1. Ventricular repolarization
  2. Ventricular depolarization
  3. Atrial repolarization
  4. Atrial depolarization
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D. Atrial depolarization — The QRS complex is ventricular depolarization; the T wave is ventricular repolarization.

Question 3

At standard speed, how much time does one small box on ECG paper represent?

  1. 0.10 seconds
  2. 0.04 seconds
  3. 1.00 second
  4. 0.20 seconds
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B. 0.04 seconds — Five small boxes make one large box (0.20 s).

Question 4

Where is the V4 electrode placed?

  1. Fourth intercostal space, right sternal border, next to the sternum
  2. Fifth intercostal space, left midclavicular line
  3. Fifth intercostal space, left midaxillary line
  4. Second intercostal space, left sternal border
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B. Fifth intercostal space, left midclavicular line — V3 goes midway between V2 and V4.

Question 5

What causes somatic tremor artifact on an ECG?

  1. A dead battery in the ECG machine
  2. Electrical interference from nearby equipment
  3. Patient movement, shivering or muscle tension
  4. Electrodes placed on the wrong limbs
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C. Patient movement, shivering or muscle tension — Keep the patient warm, relaxed and still.

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