EKG Practice Test 3 - Learn & Master ACLS/PALS


  1. ALEXANDRA says

    for question 5 in test 3: so, one “almost looking like a” QRS doesn’t make it a 3rd degree block.
    i mistook it for 3rd degree, thinking there were a lot of p-waves and one qrs.
    still learning.. 🙂

    thank you

    • ACLS says

      I recommend a thorough review of the section on bradycardia listed on this page. One of the main things is to practice by looking at EKG rhythms. Knowing what normal looks like is the best way to recognize when you see some an ekg because you’ll then immediately recognize abnormal.

      EKG rhythms

      Kind regards, Jeff

      • RF says

        1st degree has a long PR interval and is consistent.
        2nd degree type 1- The P wave has a going . going.. gone pattern which can be confusing with a third degree HB.
        2nd degree type 2 will have a consistent PR interval but will have extra P’s between complexes.
        3rd degree will have the P waves disassociated from the QRS complex so there wont be a pattern of P waves between the complexes.

    • Jesse says

      The only difference between normal sinus rhythm and a first degree heart block is that the PR interval is more than .20. A regular PR interval is .12 – .20. So if you could your small boxes, they are .04 each. 3-5 boxes is normal. Anything more than 5 boxes or .20 classifies the rhythm as a first degree heart block. Hopefully this helps!


    I am not understanding how this is SVT with a rhythm of 150. I assumed that for SVT the rhythm needs to be greater than 150, whereas sinus tach is 100-150. On other similar strips that have a rhythm of 150, the answer is usually sinus tach. What is the best way to differentiate between the two?

    Question 12

    • ACLS says

      SVT can have a rate of 150 and it may be difficult to differentiate between SVT and ST at times.

      Gathering a history and physical exam plays and important part in distinguishing the two:

      In sinus tachycardia, there is gradual onset and termination of symptoms like palpitation.

      SVT typically presents with sudden onset and termination of palpitations, light-headedness, chest pain, abnormal pulsations in the neck and dyspnea lasting between seconds to several hours.

      Less commonly, symptoms of SVT may include syncope secondary to vasovagal response or compromised cardiac output, and polyuria secondary to the diuretic effects of atrial natriuretic factor.

      Sinus tachycardia is usually due to physical, emotional, pathological (fever, hypovolemia, anemia, anxiety, infection, malignancy, myocardial infarction, congestive heart failure, pulmonary embolus, thyrotoxicosis) or pharmacological (caffeine, alcohol, nicotine, salbutamol, aminophylline, atropine, cocaine, doxorubicin, daunorubicin) stimulus.

      Majority of the SVT occurs without any underlying cause.

      Kind regards, Jeff

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