ECG: the first step

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Direction and polarity of the representative leads

There are 12 leads in a standard electrocardiogram. Representative leads are as follows.

Lead Positive deflection Negative deflection
I left right
aVF inferior superior
V2 nearly anterior nearly posterior

Achievement Quiz

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  1. Which direction (component) of the cardiac vector would elicit a positive/negative ECG deflection in each lead? Select from anterior/posterior/left/right/superior/inferior.

    Lead Positive deflection Negative deflection
    I anterior/posterior/left/right/superior/inferior anterior/posterior/left/right/superior/inferior
    aVF anterior/posterior/left/right/superior/inferior anterior/posterior/left/right/superior/inferior
    V2 anterior/posterior/left/right/superior/inferior anterior/posterior/left/right/superior/inferior

    Answer

  2. How would the electrocardiograph needle in lead I, lead aVF, and lead V2 deflect when the cardiac vector is directed as shown?




    Answer

    Projection to each lead

    Lead I
    Lead aVF
    Lead V2



  3. Which direction would the cardiac vector be, when the electrocardiograph needle is deflected like this?




    Answer

    Projection to each lead

    Lead I
    Lead aVF
    Lead V2



  4. How would the electrocardiograph needle in lead I, lead aVF, and lead V2 deflect when the cardiac vector is directed as shown?




    Answer

    Projection to each lead

    Lead I
    Lead aVF
    Lead V2



  5. Which direction would the cardiac vector be, when the electrocardiograph needle is deflected like this?




    Answer

    Projection to each lead

    Lead I
    Lead aVF
    Lead V2



  6. How would the electrocardiograph needle in lead I, lead aVF, and lead V2 deflect when the cardiac vector is directed as shown?




    Answer

    Projection to each lead

    Lead I
    Lead aVF
    Lead V2



  7. Which direction would the cardiac vector be, when the electrocardiograph needle is deflected like this?




    Answer

    Projection to each lead

    Lead I
    Lead aVF
    Lead V2



  8. How would the electrocardiograph needle in lead I, lead aVF, and lead V2 deflect when the cardiac vector is directed as shown?




    Answer

    Projection to each lead

    Lead I
    Lead aVF
    Lead V2



  9. Which direction would the cardiac vector be, when the electrocardiograph needle is deflected like this?




    Answer

    Projection to each lead

    Lead I
    Lead aVF
    Lead V2



  10. How would the electrocardiograph needle in lead I, lead aVF, and lead V2 deflect when the cardiac vector is directed as shown?




    Answer

    Projection to each lead

    Lead I
    Lead aVF
    Lead V2



  11. Which direction would the cardiac vector be, when the electrocardiograph needle is deflected like this?




    Answer

    Projection to each lead

    Lead I
    Lead aVF
    Lead V2



  12. How would the electrocardiograph needle in lead I, lead aVF, and lead V2 deflect when the cardiac vector is directed as shown?




    Answer

    Projection to each lead

    Lead I
    Lead aVF
    Lead V2



  13. Which direction would the cardiac vector be, when the electrocardiograph needle is deflected like this?




    Answer

    Projection to each lead

    Lead I
    Lead aVF
    Lead V2