EKG Basics

The center of the heart (Central Terminal)

Augmented leads use what as the (-) pole?

10 seconds

A 12-lead ECG depicts how much time?

Ventricular depolarization is originating from the AV node and there are no ectopic depolarizations.

A P:QRS ratio of 1:1 indicates what?

A depolarization moving Toward a (+) pole creates an Upward complex. A depolarization moving Away from a (+) pole creates a Downward complex.

A depolarization moving ________a (+) pole creates an __________ complex. A depolarization moving ________ from a (+) pole creates a __________ complex.

J Point

A point on the QRS complex where the depolarization is completed and repolarization starts. This is where the QRS segment turns horizontal and becomes the ST segment.

V1, V2, and V3

Any Q wave in these three leads is abnormal.

Find an R wave on a thick line. Count the large boxes until the next one. 1 box: 300 2 box: 150 3 box: 100 4 box: 75 5 box: 60 6 box: 50

Identify the numbers in the box method of determining rate.

Lead I: RA (-) --> LA (+) Lead II: RA (-) --> LL (+) Lead III: LA (-) --> LL (+) aVR: Central Terminal (-) --> RA (+) aVF: Central Terminal (-) --> LL (+) aVL: Central Terminal (-) --> LA (+)

Identify where the Frontal Leads are placed/oriented.

V5 and V6

Lack of a Q wave in which leads is abnormal?

Lead II V1 V2

The P wave is best visualized in which three leads?

The QT Interval should be < 1/2 of the R-R Interval.

The QT Interval should be ________ of the R-R Interval.

Isoelectric/flat

The ST segment represents the refractory period of the ventricles and should be this.

The height of the T wave should be 1/3 the height of the R wave in that lead.

The height of the T wave should be ______ the height of the R wave in that lead.

< 0.12s

The width of the QRS complex represents the conduction through the ventricles. What is the normal width of the QRS complex?

U Wave

This is a wave seen after a T wave. It is usually smooth and rounded. It is an abnormal finding that represents electrolyte abnormalities such as hypokalemia.

QTc

This is the QT interval after it is corrected for HR.

S Wave

This is the first downward deflection after an R wave. It represent depolarization of the Purkinje Fibers.

R Wave

This is the first upward deflection after a P Wave. It represents ventricular depolarization.

PR Interval

This is the start of the P wave to the start of the QRS complex.

QT Interval

This is the start of the QRS segment to the end of the T Wave.

QRS Complex

This represents the depolarization of the ventricles. AV Node --> Left and Right bundle branches --> Purkinje Fibers

PR Segment

This represents the refractory period of the atria and the AV Node pause.

ST Segment

This represents the ventricular refractory period.

T Wave

This represents ventricular repolarization.

Q Wave

This wave is the first downward reflection following a P wave. It represents septal depolarization.

P Wave

This wave represents Depolarization of the atria, starting with the SA node, going through the interatrial pathway, and also going through the internodal pathway to the AV node.

1. Check Standardization 2. Rate 3. Rhythm 4. P Waves 5. QRS

What are the five steps to reading an EKG Rhythm strip?

1. Morphology: Sinus, ectopic atrial, junctional 2. PRI: Normal, short, prolonged 3. P:QRS Ratio: Does every P wave have a QRS right after it?

What are the three components to assess in a P Wave?

Atrial depolarization: SA Node --> Bachmann Bundle SA Node --> AV Node

What does the P Wave represent?

The "hold up" at the AV junction. Normal distance is .12s to .20s

What does the PR Interval represent?

Refractory period of the atria AND the AV Node Pause.

What does the PR Segment represent?

Septal Depolarization

What does the Q Wave represent?

Ventricular Depolarization: AV Node --> Bundle of His --> Bundle Branches --> Purkinje Fibers

What does the QRS Complex represent?

Ventricular depolarization

What does the R Wave represent?

Depolarization of Purkinje Fibers

What does the S Wave represent?

Ventricular Refractory Period

What does the ST Segment represent?

Ventricular Repolarization

What does the T Wave represent?

The center of the heart (Central Terminal)

What is the (-) pole for the Transverse Leads?

A P:QRS ratio of 1:1 indicates that depolarization is conducting through the AV node and there are no ectopic ventricular depolarizations.

What is the ideal P:QRS ratio?

.12s - .20s

What is the normal distance of the PRI?

V1: 4th IC right sternum V2: 4th IC left sternum V3: Between V2 and V4 V4: 5th IC left midclavicular V5: 5th IC anterior axillary V6: 5th IC midaxillary line

What is the placement of the transverse leads?

SA Node: 60-100 AV Node: 40-60 Purkinje: 20-40 (no es bueno)

What is the resting rate of the following pacemaker cells? SA Node AV Node Purkinje Fibers

Sinus P Wave

What type of P Wave is presented here?

When checking the standardization of an EKG, 1mV should be represented by 10mm high and speed should be 25mm/sec.

When checking the standardization of an EKG, 1mV should be represented by ________ high and speed should be ________.

300 150 100 75 60 50 43 37

When using the box method, what are the numbers in order by box?

- Leads I, II, and III - aVR, aVF, and aVL

Which leads are in the frontal plane?

V1-V6

Which leads are in the transverse plane?