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Flashcards in EKG Deck (46):

What is the function of the SA node?

Sinoatrial (SA) Node

“Pacemaker of the heart”

Rate of 60-100 bpm (intrinsic rate)

Begins atrial systole, and transmits electrical impulse to AV node


What is the function of the AV node?

Atrioventricular (AV) Node
Slows conduction to ventricles
Delay allows for “Atrial Kick”
completes ventriclular filling
~20% of Cardiac Output
Back-up pacemaker in case of SA conduction failure
Rate of 40-60 bpm (intrinsic rate)


How is blood transported into the Ventricles?

2 ways
80% from pressure gradient 20% from atrial kick


What is the Intrinsic rate of the AV node?

40 - 60 bpm


Bundle branches can have what rate?

20 - 40


What happens in Diastole?

Ventricles are filling and relaxed as tricuspid and mitral valves are open

Semilunar valves are closed.

Coronary Arteries are passively filled with blood that is past the Aortic valve


What happens during Atrial Systole (P-wave)?

Atrial Kick that give the last 20% of blood from atria

Greater pressure in ventricles than atria closes AV valve


What Happens in Isovolumetric Ventricular Contraction?

Ventricles contract, all valves closed rapidly increasing pressure.
Volume not changing in left and right ventricle


What Happens in ventricular systole?

Incresed pressure from ventricle contraction opens semilunar valves to release blood into arteries.


What is a heart Murmur?

regurgitation of blood back to original chamber due to valve weakening.


What Happens in Isovolumetric Relaxation?

Vents repolarize
Ventricle pressure decreased, AV valves open


What is the P-wave on an EKG?

Atrial depolarization, contraction


When reading an EKG, a small box represents what length of time?
A big box represents what length of time?

Small box = .04 secs
Big box = .20 secs


When reading a rate, if an R-wave peaks on every other line, what is the rate?

Remember: on every line = 300
if it skips 2 lines then beats = 100
if its skips 3 lines then beats = 75
if its skips 4 lines then beats = 50


What is the normal height and length of a P-wave?

less then 2.5 mm high

less .12 seconds or (3 sm boxes)


What is the normal length of a PR interval?

.12-.20 seconds (or 3-5 sm boxes)


What is the normal length of a QRS wave?

.06-.12 seconds (or 1 ½ to 3 sm boxes)


What is the ST segment and what conditions can it show?

It is normally an isoelectric line that happens after the QRS wave and right before the T wave.
An elevated ST segment may mean M.I. (code STEMI)
A depressed ST segment can occur in Angina


What is a T-wave?

repolarization of the muscles

T wave is typically larger than P wave and asymmetric, elevated with electrolyte imbalances


What is the process in reading an EKG?
6 things

-Is the rhythm regular?
-Determine the rate
-Norm 60-100
-P waves: are they normal? Is there a QRS after every one?
-PR interval: normal length?
-QRS normal?
-ST segment isoelectric and T waves normal?


What is a bi or tri gemini?

Its a term used in regularly irregular beats.
bi are irregular beats that happen ever other beat
tri are irregular beats that happen every 3rd beat


What is a couplet or a triplet?

Its a term used for irregular beats.
Couplet are 2 irregular beats that occur but then return
Triplets are 3 irregular beats


What are the 3 types of T waves?



What is a normal HR?



What are the characteristics of a Normal Sinus Rhythm?

HR - 60 - 100
Regular rhythm
There is a P wave before every QRS
PR interval of .12-.20 secs
QRS of less than .12


What are the characteristics of Sinus Brady?
What is the treatment?

HR - Less than 60
Regular rhythm
There is a P wave before every QRS
PR interval of .12-.20 secs
QRS of less than .12

Treatment: Atropine


What are the characteristics of Sinus Tachycardia?

HR - greater than 100
Regular rhythm
There is a P wave before every QRS
PR interval of .12-.20 secs
QRS of less than .12

Treatment: Need to find underlying cause.
Can use oxygen
Pain meds


What is a PAC?

Premature Atrial Contraction
Ectopic focus, atrial fires before SA node impulse

Can be Multifocal or Unifocal


What does unifocal and Multifocal mean?

It describes the origin of the ectopic beat outside of the normal electrical pathways.

Unifocal means the beat comes from one place

multifocal comes from multiple parts of the heart.


What are the causes for a PAC?

Atrial hypoxia, irritability

COPD due to dilated, hypertrophied atria which are more irritable

Digitalis toxicity



What is the treatment for a PAC?

Rarely needs treatment


What is PSVT and a PAT?

Paroxsymal Supraventicular tachycardia
Paroxsymal Atrial Tachycardia

dysrhythmias that correct itself.

Coughing or bearing down can bring rhythm back


What is an Atrial Flutter?

Very irritated focus – atrial contraction 250-400

AV node doesn’t (can’t) pass all impulses;

ventricular rate is controlled

Atrial kick diminished

Characteristic sawtooth pattern


What are the causes of A-flutter?
4 causes

AMI, Cardiac Surgery, hypoxemia, PE


How do you treat A-flutter?

Goal to control rate

Drugs: amiodarone, digoxin

Symptomatic (palpatations, angina, hemodynamic
compromise) = cardioversion


What is the difference of Cardioversion and D-Fib?

Cardioversion is timed to send a shock at an R-wave
while D-fib is not synchronized.


What is A-fib?
at least 5 things

Multiple ectopic impulses

Erratic quivering of atria

NO effective atrial contractions occur

Conduction thru AV node is slow or fast

Atrial rates can be 350-650


What are some risks of A-fib?

PE risk

Hemodynamic effect depends on patient tolerance of decreased CO


What is the treatment of A-fib?

anticoagulation (if patient has been in A-fib for an unknown time)
If symptomatic cardioversion.


What is a first degree Heart block?

What is the treatment?

Normal SA impulse

Delayed at AV node (PR interval longer than 0.2 seconds ( 5 boxes)

No treatment


What is second degree heart block TYPE 1?

What is the treatment?

PR interval gets longer with each beat until
transmission to ventricle is dropped

P wave is seen without QRS

No treatment


What is second degree heart block TYPE 2?

What is the treatment?

PR intervals remain Constant

Impulses are intermittently blocked at Bundle of His or Bundle branch

More P waves than QRS

Atropine then pacemaker


What is 3rd degree heart block?
Complete heart block

What is the treatment?

No Beats conducted to ventricle from atria
Atria and ventricles depolarize independently

SA node depolarizes atria, Bundle of His or
Bundle branches depolarize ventricles

Normal QRS if Bundle of his, wide complex if
below due to slower conduction rates



what is a Idioventricular Rhythm?

ventricles take over if Atria aren’t firing
Rate : 20-40
also called Ventricular escape rhythm

Do NOT try to abolish this rhythm
Lidocaine contraindicated

permanent pacing may be required, this is not a
reliable rhythm


What is ventricular tachycardia?

Rhythm usually regular

Rate is 100-250

P waves not usually present

Wide QRS

three PVCs in a row = V-Tach


What is the difference between an Idioventricular rhythm and a Junctional Rhythm?

An Idioventricular Rhythm occurs when SA node doesnt set pace for ventricular rate and an ectopic focus is use to set the pace.

Junctional Rhythm is controlled by the AV node and appears to be have a normal QRS. P wave may be present but can look inverted.