EKG 12/6 challenge

EKG Page

Test 1 Study Guide
PEP 475 Electrocardiography

Electrophysiology
1. Who was Waller? Who was Einthoven?
2. Define automaticity.
3. Draw the heart’s electrical conduction system. What is the job of the SA and AV node?
4. What part of the heart conducts electrical impulses the fastest? How about the slowest? Why?
5. What is the resting membrane potential in millivolts? What is the threshold potential for conduction of an impulse in a contractile cell?
6. Describe in detail what occurs in Phases 0-4 of the action potential for a contractile cell. Draw the action potential and label the phases.
7. What ion do autorhythmic cell membranes allow to leak in? What happens to heart rate if the membrane becomes more leaky to this ion?

Theoretical Basis of EKG
1. What two characteristics do all vectors posses?
2. What type of deflection occurs on the EKG when a vector travels towards, away, and perpendicular to an EKG lead?
3. How many limb leads make up the 12 lead EKG? How many precordial leads? Name them all. What plane are the limb leads in? The precordials?
4. What is a bipolar lead? What is a unipolar lead?
5. Individually draw the limb leads. Label the positive and negative ends of each lead.
6. Draw and label Einthoven’s triangle.
7. Why are the augmented limb leads "augmented"?
8. Draw and label the leads that comprise the Hexaxial system.
9. What leads are the inferior leads? The anterior leads? The lateral leads? The posterior?

Sequence of cardiac depolarization
1. Draw the 5 main vectors of the heart.
2. Based on the 5 main vectors, determine what each lead (limb and precordial) should normally look like.
3. Why does the mean QRS vector travel downward and to the left in the body?

Determination of heart rate
1. What is the length and height of one small square on the EKG paper? How many seconds is one small square? What about one large box? How many large boxes in 6 seconds?
2. How many large boxes make up a standard calibration pulse? What is it in milivolts?
3. What are two methods to determine heart rate if the rate is regular? What if the rate is irregular?
4. Be able to count heart rates using the triplet and 6-second method.

EKG waves, intervals, and segments
1. Draw one EKG cycle (P to T wave). Label the P wave, PR interval, PR segment, QRS complex, J point, ST segment, T wave, and QT interval. What do each represent?
2. What is the normal duration for the PR interval, QRS complex, and QT interval?
3. Is the ST segment normally isoelectric?
4. What is the normal height and duration of the P wave? What leads are P waves normally upright, inverted, and biphasic?
5. What leads usually contain the larget P waves?
6. What is the height and duration of a normal Q wave? What leads are these seen in?
7. What leads are T waves normally upright and inverted?

Electrical Axis
1. What are the first 4 steps of Jeff’s 12 lead checklist?
2. Draw the Hexaxial system. Label the leads, positive and negative ends of those leads, and the assigned degrees for each "spoke" of the hexaxial system.
3. Draw the boundaries and degrees for normal axis, right axis deviation, left axis deviation, and extreme right axis deviation on the hexaxial system.
4. What degree does the mean QRS vector normally travel at?
5. Determine which limb leads are perpendicular to one another.
6. Be able to determine which quadrant the Mean QRS vector is in by looking at Lead I and AVF
7. List the steps for determining the Mean QRS vector axis.
8. Be able to determine the axis of the Mean QRS vector.

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