Prehospital 12 lead ECG quiz for the kitchen table

1. Which of the following statements about axis determination is false?

a.) The normal quadrant is the left inferior quadrant.
b.) When leads I and aVF show an upright QRS complex, the axis is in the normal quadrant.
c.) For the axis to be normal, the QRS complex in lead I can be negative as long as the QRS complex in leads II and III are positive.
d.) If the QRS complex in lead aVL is equiphasic, it means the heart’s mean electrical vector is moving perpendicular to that lead.

2. You attach the limb leads and the monitor shows artifact in leads I and III. You should:

a.) Trouble shoot the white electrode.
b.) Trouble shoot the black electrode.
c.) Trouble shoot the red electrode.
d.) Trouble shoot the green electrode.

3. Your patient is a 68 year old male complaining of chest pain. You capture a 12 lead ECG which shows ST segment elevation in leads III and aVF and ST segment depression in lead aVL. What is the most likely cause?

a.) Pericarditis
b.) Acute anterior ST elevation myocardial infarction
c.) Acute inferior ST elevation myocardial infarction
d.) Benign early repolarization

4. True or false. Acute myocardial infarction is the most common cause of ST segment elevation in chest pain patients.

a.) True
b.) False

5. You are treating a patient with shortness of breath. You capture a 12 lead ECG which shows sinus rhythm, a QRS duration of 148 ms, an rS complex in lead V1, and a monophasic R wave in lead I. The T waves are discordant with the QRS complex throughout the ECG. The most likely explanation is:

a.) Left ventricular hypertrophy
b.) Left bundle branch block
c.) Nonspecific intraventricular conduction defect
d.) Right ventricular hypertrophy with strain pattern

6. Which of the following statements about acute inferior ST elevation myocardial infarction is false?

a.) Patients with inferior ST elevation myocardial infarction are candidates for immediate reperfusion therapy.
b.) Patients with inferior ST elevation myocardial infarction tend to have a better prognosis than patients with anterior ST elevation myocardial infarction.
c.) Patients with inferior ST elevation myocardial infarction may also be experiencing right ventricular infarction.
d.) The most common arrhythmia associated with inferior myocardial infarction is sinus tachycardia.

7. You are treating a 35 year old male complaining of anxiety and palpitations. He states that he has a history of arrhythmias. The monitor is attached and shows a slightly irregular wide complex tachycardia at a rate of 258. A 12 lead ECG is captured. The computerized interpretive statement reads:

• Supraventricular tachycardia
• Right bundle branch block, plus right ventricular enlargement
• Lateral infarct, age undetermined
• T wave abnormality – consider inferior ischemia

The patient is hemodynamically stable and an IV has been established. You should:

a.) Suspect the possibility of an accessory pathway and provide supportive care only. Provide synchronized cardioversion if the patient becomes unstable.
b.) Give 150 mg Amiodarone mixed in a 50 ml bag of 0.9 NS over 10 minutes.
c.) Perform vagal maneuvers. If unsuccessful, give Adenocard, rapid IV push followed with a flush.
d.) Prepare the patient for immediate synchronized cardioversion.

8. You are called to the home of a 88 year old male with a complex medical history including heart failure and renal insufficiency. The chief complaint is general weakness, mild dyspnea, and vomiting. Medications include a beta blocker, an ACE inhibitor, a diuretic, and potassium supplements. A 12 lead ECG is attached and shows an undetermined rhythm with wide QRS complexes at a rate of 80. You suspect:

a.) Hyperkalemia
b.) Hypokalemia
c.) Acute pulmonary edema
d.) Acute myocardial infarction

9. Which of the following statements about reciprocal changes is false?

a.) Reciprocal changes are strong supportive evidence that ST segment elevation represents acute myocardial infarction.
b.) Leads I and aVL are reciprocal to each other.
c.) Leads I and II are reciprocal to each other.
d.) Leads III and aVL are reciprocal to each other.

10. Which of the following statements about prehospital 12 lead ECGs is false?

a.) For patients with suspected ACS, a prehospital 12 lead ECG should be captured with the first set of vital signs.
b.) If you are close to the hospital, it is more important to give nitroglycerin than capture a prehospital 12 lead ECG.
c.) You should perform serial prehospital 12 lead ECGs to record dynamic changes in supply vs. demand characteristics that might indicate an acute coronary syndrome.
d.) Poor data quality can lead to incorrect computerized interpretive statements on the 12 lead ECG.

1.) C
2.) B
3.) C
4.) B
5.) B
6.) D
7.) A
8.) A
9.) B
10.) B


  • SoCal Medic says:

    Thanks for the refresher. I need to review the axis deviation along with the Wave Terminology, the rS through me there. Simply put, I dont use it enough, and if you do not use it, you lose it. Thanks again Tom.

  • Tom B says:

    You’re welcome. I’ll be covering RBBB and LBBB in more detail in the coming months.Tom

  • Casey says:

    That was fun! I knew more than I thought I did; guess reading all of your posts with all of that terminology has really helped! Thank you!

  • Hillis says:

    Thank you Tom !!
    Some points i did not understand, would you please if you don’t mind explain..
    WHY Patients with inferior ST elevation MI tend to have a better prognosis than with anterior STEMI.
    Usually patients with inferior MI are more prone to arrythmia , cardiogenic shock and usually inferior MI is associated with lateral, posterior or involve the right ventricule ( of course that depend which artery is occluded) but in all cases it increases the mortality rate, is that true ?that doesn’t mean that answer d is not correct but i think b is also correct !!
    In Q5. amiodarone is not even save for SVT with abberancy so amiodarone can be given safely to the patient !!.

  • Tom B says:

    Dr. Hillis –

    I am basing this on the Fibrinolytic Therapy Trialists’ (FTT) Group that showed a tremendous benefit to fibrinolytic therapy for acute anterior STEMI (in terms of lives saved per 1000 patients treated) and a much more modest benefit for acute inferior STEMI.

    Consider that RCA is more likely to effect the right ventricle and inferior wall of the left ventricle while circulation off the LMCA (especially the LAD) is more likely to effect the left ventricle and cause wall motion abnormalities or myocardial damage that will cause cardiogenic shock.

    So while I agree that RV infarction patients are dependent on central venous pressure to maintain cardiac output and nitroglycerin must be used with caution, left-sided pump failure is more closely associated with acute anterior STEMI, according to the sources I’ve read, which of course could be wrong.

    In the setting of irregular or polymorphic rhythms with rates greater than 250 we must be mindful of the presence of an accessory pathway. While you are correct that the 2005 AHA ECC Guidelines condoned amiodarone in this setting, there is scant support in the peer reviewed literature to support this practice, and in fact Amal Mattu, M.D. has searched the literature extensively and found evidence of harm.

    I quote him here:


  • Hillis says:

    Thanks Tom for responding, very professional explanation.

    No doubt that the definitive treatment for AF with WPW is cardioversion but on the other side no clear or definitive contraindication for amiodarone esp. in hemodynamically stable patient it’s still written in literature !!.

    Regardig the above research or study is it proved by the AHA ECC ?

  • Leslie says:

    I have my certification for EKG Technician and I would like to make a career as a EKG/Cardiac/Telemetry Monitor Technician.  Where would I go to learn more about this.
    Are a lot of jobs in this field.
    I reside in New York City, NY; can someone advise me on this matter.
    Thank you.
    Leslie McDermott

  • Ben says:

    Leads I and aVL are reciprocal to each other? No they're not

  • Correct. They are not. Read the question!

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