EKG Flashcards
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?
150 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?
Normal
Peaked
Inverted
What is a normal HR?
60-100
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?
Treatment?
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
Stress
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?
CVA
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) dixgoxin, esmolol, amiodarone. 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
Pacemaker
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.
