Basics of the Electrical System, Lead Placement, Labeling and Measuring, Sinus Rhythms, SVT, Asystole

How should you place leads in a 5 lead system

• Clouds over grass

  • White RA —> just below right clavicle

  • Green RL —> Lower edge of right rib

• Brown V1 —→ Fourth intercostal space immediately right of sternum

• Smoke over fire

  • Black LA —> just below left clavicle

  • Red LL —> lower edge of left rib

Where to place leads in a 3 lead system

RA —> just below right clavicle

LA —> just below left clavicle

G —> just below pectoral muscles, lower edge of left rib cage

Where to place positive and negative ends in 3 lead ecg (lead 1)

Negative on left point of triangle, arrow points to positive sitting on the right end

Where to place positive and negative ends in 3 lead ecg (lead 2)

Negative on left point of triangle, arrow points to the positive sitting on bottom point of triangle

Where to place positive and negative ends in 3 lead ecg (lead 3)

Negative is on right point, arrow points to positive end on bottom point of triangle

Whip out a heart diagram and label the sinoatrial node, atrioventricular node, atrioventricular bundle (bundle of his), bundle branches, purkinje fibers

answer is on page 25

What is the electrical activity associated with the p wave

atrial depolarization, SA —> AV

What is the electrical activity associated with the pr segment

delay at av node

What is the electrical activity associated with the qrs complex

ventricular depolarization, bundle branches

What is the electrical activity associated with the T wave

ventricular repolarization

What is the electrical activity associated with the isoelectric line

no electrical activity

How many seconds is each small box

.04 sec

How many secs in one big box

.20 sec

How many small boxes in 1 minute

1500

Explain the first way to measure heart rate (for regular rhythms)

• find two regular points and measure the number of small boxes between those two points, divide by 1500 to get bpm

  • Measuring R-R and dividing that # boxes into 1500 gives ventricular rate

  • Measuring P-P and dividing that # boxes into 1500 gives atrial rate

Explain the first way to measure heart rate (for irregular rhythms)

Measure the two complexes closest together, and the two complexes farthest apart

• take number of boxes in between and divide into 1500

Provides a range

Explain the first way to measure heart rate (for rhythms with different atrial and ventricular rates)

• measuring from P-P shows atrial rate

• Measuring from R-R shows ventricular rates

  • Helpful when rhythm is some form of a block or an atrial flutter

Explain the second way to measure heart rates

Start counting from QRS and count down from number line above 1 large box at a time until you get to the next QRS complex

(lowks watch a video on this, i dont understand. im not gonna teach myself rn tho cause its less accurate than 1500 method)

Explain the third way to measure heart rates (for irregular rhythms)

• Look at six second strip (each line below the grid paper indicates one second)

• count number of QRS complexes

• multiplying number by 10 will gives ventricular rate

• Counting p waves and multiplying by 10 gives atrial rate

What questions should you answer to help determine rhythms

1) mark strip to indicate p wave, qrs complex, mark beginning and end of PRI, QRS, QTI

2) does rate look fast (>100) or slow (<60)

3) Does it have a p wave? A QRS complex? a normal t wave?

4) is the rhythm regular? R-R regular? P-P regular?

5) are there any extra or early beats that seem out of place

From where to where is the PR interval

beginning of P wave to before the QRS complex starts (before Q)

What is a normal PRI

.12-.20 seconds (3-5 little boxes)

From where to where is the QRS

Beginning of Q to end of S

What is a normal QRS

less than or equal to .12 seconds (2.5 little boxes)

From where to where is QTI

Beginning of Q to end of T

What is a normal QTI

.30-.40 seconds (7.5-10 little boxes)

How to measure seconds of PRI, QRS, QTI

number of little boxes x .04

What is an artifact

anything on EKG paper not caused by heart’s conduction system

• interferes with ability to read an EKG strip

What are the three main types of artifacts (draw an example!)

• 60 second cycle interference (some other electrical activity in room is interfering with reading??)

• muscle artifact or movement (patient moved)

• wandering baseline (patches need to be changed)

what to do when an artifact occurs

• change ekg patches

• clean off chest with alcohol pad if patient is sweaty or has lotion on

• taping the wire to prevent the lead wires pulling

What does it mean if a QRS is greater than .12 seconds

bundle branch block

How to determine if a rhythm is a sinus rhythm

PRI, QRS, and QTI are normal

What sinus rhythm is it if the heart rate is less than 60bpm

sinus bradycardia

What sinus rhythm is it if heart rate is 60-100bpm

normal sinus rhythm

What sinus rhythm is it if heart rate is above 100 bpm

sinus tachycardia

What sinus rhythm is it if there is a slight variation to the heart rate, but everything else is normal

sinus arrhythmia

What sinus rhythm is it if everything is normal but PRI is greater than .20

Sinus rhythm with 1st degree heart block

How to determine if rhythm is supraventricular tachycardia

• heart rate above 150 (children —> above 180, infants —> above 220)

• hard to distinguish p from t

• regular rhythm and QRS within normal limits

• QRS measurable, PRI and QTI not measurable

Asystole

• absence of all waves and intervals

• baseline should have slight wave

  • if absent, ensure leads are on

• this rhythm never has a pulse

• this patient is dead :’)