Dysrhythmias Flashcards
Rate that the sa node should be between for a normal heart
60-100
What does the sa node do?
It is the pacemaker of the heart and it creates the impulse which then travels to the atria
What is conduction?
what allows for the ATRIA to contract?
Conduction is when the the muscle cells of the atria contract.
The AV node allows for the atria to contract by slowing the impulse down. This allows time for the atria to contract and ventricles to fill
Where does the impulse travel in order for the ventricles to receive the impulse to contract?
The impulse goes from AV node»_space; bundle of his»_space; perkinje fibers in the ventricles
systole
muscle contraction
diastole
muscle relaxation
What does heart depolarization correlate with?
Depolarization corresponds with heart muscles contracting like a wave through the heart
When the heart repolarizes the heart is doing what?
relaxing
What is the impulse doing when the ekg shows a P-wave?
The atria is depolarizing meaning conduction (remember this happens int he atria) is occurring there so there will be corresponding muscle contraction.
What is the impulse doing when the ekg shows a QRS?
The ventricles are just depolarizing and experiencing conduction.
What is going on if there is a T-wave on the ekg?
Ventricles are repolarizing or relaxing
What is the QT interval on an ekg?
Time from ventricles depolarizing to ventricles repolarizing.
What is an ST segment?
When do we common see it?
Early repolarization
Commonly seen elevated with an acute MI
Time for a ONE small box on the ekg
0.04 seconds
Time for ONE large box on the ekg
How many small boxes are in a large box?
0.20 seconds
5 small boxes inside a large box
Time for FIVE large boxes on the ekg
5 large boxes will equal 1 second
How many boxes on an ekg gives you 6 seconds?
30 large boxes
so 150 small boxes
What is positive deflection
Waveforms that move up the paper
First question you ask yourself when you’re assessing the cardiac rhythm on ekg?
Does the rhythm look regular?
- meaning does it look spaced out evenly
Second question you ask yourself when you’re assessing the cardiac rhytm on an ekg?
Are all the pieces there?
- P wave, QRS, T wave?
Third question you can ask yourself when assessing the cardia rhythm on the ekg?
What is the rate?
- add up the amount of boxes in between R intervals (top). then take 1500/n.
Fourth question you can ask yourself when assessing cardiac rhythm on the ekg to double check?
Check and see is the patient presentation lines up with your findings.
Do they have symptoms? Is the issue new or has it always been chronic?
When someone says your st segment is “isoelectric” what do they mean?
At baseline or straight
How big is the Pwave not supposed to exceed?
Should not exceed 1 box in length and 1 box in height
1x1
What is the time length and box length of a normal QRS complex?
0.08-0.12 seconds
2-3 horizontal boxes
What is the time length and box length of a normal PR interval?
How is this measured?
0.12-.20 seconds
3-5 horizontal boxes
Beginning of the P wave to the onset of the QRs. (initial wave can sometimes be an R isnead of the Q)
T/F
Sa node stimulates the heart for a rate of 40-60 bpm and the impulse travels to the ventricles
False.
Sa node heart rate is the higher one of 60-100.
The impulse of the sa node travels to the atria.
T/F
It is common for normal sinus rhythms to change during non-strenuous movements
What is treatment for normal sinus?
False.
Normal sinus rhythms are supposed to be able to remain steady when you aren’t straining yourself
Treatment includes monitoring closely (bc it can all change in an instant)
What is the definition of a normal sinus rhytm?
It is when all the correct components of an ekg are there and the HR is within the normal limits of 60-100 bpm (remember - the SA node is the pacemaker here so it should be between these numbers if the heart is NORMAL)
What is sinus bradycardia?
Correct components of the ekg but the HR is below 60 (or bradycardic)
T/F
Sinus bradycardia only occurs in a diseased heart
False
Sinus bradycardia can be present in normal and a diseased heart - you don’t have to be completely unhealthy to have it.
Ex: athletes
What is the clinical presentation of sinus bradycardia (as in a clue where you don’t have to look at the ekg)?
You look for signs of decreased cardiac output.
Fatigue
Thready pulse
Diaphoretic and sweaty
DOB
Decreased UO
confusion
T/F
You only ever need to treat sinus bradycardia if the client is having symptoms of distress
True.
What is the first treatment for sinus bradycardia?
What are the other meds you can give?
Machine that can help?
Atropine
Dopamine drip, Epinephrine
Cardiac pacing
- gives jolt if the hr drops below 60
When giving dopamine for sinus bradycardia what is the dosage?
low dose effect
high dose effect
2-10 mcg/kg/minute
helps increase contractions and hr
low dose = increase renal perfusion due to vasodilation
high dose = acts as presser for faster HR due to vasoconstriction
Explain how low and high dose effects of dopamine can affect renal perfusion
If you need more perfusion to kidneys (bc the hr is too low to perfuse) you can give low dose to dilate the vessels
if you were to give a high dose you can cause too much restriction and cause renal failure
If a pt is in sinus bradycardia and they are having angina why is this and how can we help them?
Pt is probably having angina due to not getting enough o2 from low HR. So, we can give them 02.
Body states that begin with an “H” which can lead to sinus bradycardia?
Hypoxia
Hypo/Hyperkalemia
Hypothermia
Hypovolemia
How can hypoxia cause sinus bradycardia?
Well there just low on 02 already
How can Hypovolemia cause sinus bradycardia?/
Not having enough fluids in the body can cause HR to slow (but be careful the same goes for tachycardia too)
What site stimulation can cause sinus bradycardia?
What procedure can cause the sinus bradycardia rt to it?
Vagal stimulation from barring down, coughing, vomiting
intubation can stimulate the vagal nerve and cause it
Causes of sinus bradycardia that begin with “T”?
“PT”?
Toxins
Trauma
Tamponade
Thrombosis
Pneumothorax
H & T????
Drugs that can cause sinus bradycardia
Digoxin
Beta Blockers
Verapamil
Diltiazem
(the drugs youd give for tachy essentially)
- make sure you monitor patient or even make sure there are perimeters
Atropine dosage for bradycardia?
Push speed?
- 5 mg IV push
- can repeat up yo 3 mg
Push it fast!!! as well as the flush
Second line bradycardia drug?
What is the caution here?
Dopamine 2-10 mg/kg/min
Caution with heart blocks and active MI
- if we increase hr, a heart that is already exhausted will become even more exhausted
also know some doctors will choose Epi (depends on doctor). same dosage too
More invasive treatment for bradycardia that just won’t go away?
Two types and their meaning?
Pacemaker placement that can be temporary or permanent
transcutaneous - on skin . delivers shock set to 60 zou
transvenous - invasive at central venous access. gives shock
Treatment of choice for patients with symptoms of bradycardia with signs of poor perfusion (if meds aren’t working)?
Transcutenous - on skin
What is Sinus Tachycardia?
Why does it occur?
It is when all the components are there so its sinus but the HR is faster making it tachycardia. 100-150 rate
The sa node rapidly fires
T/F
Sinus tachycardia is a rapid contraction in response to a condition of an abnormal heart
False. It is usually in a normal heart
Eight main causes of sinus tachycardia
Which is a main indicator of sepsis?
Drugs Disease Pain FEVER Excitement or caffeine Hypovolemia MI HF
The fever. If they have tachy it can be from infection
What is sinus tachycardia characterized by?
- Normal RESTING heart rate but with an exaggerated postural sinus tachy with or without orthostatic (pt can get tachycardic but won’t have changes in BP)
- decreased cardiac output
What does clinical presentation of sinus tachycardia rely on?
The rate and how well the pt can handle it
Why do patients with sinus tachycardia experience:
Dizziness
Hypotension
Angina and chest pain
Dizziness = due to the HR being too fast, the rest of the organs of the body may not be perfused enough and could be starving
Hypotension = with prolonged tachy
Angina = due to no oxygen to heart
- can put them on O2
How can psychological stress cause sinus tachycardia?
What other obvious causes of tachycardia are there?
Stress can make your HR increase, duh.
Pain
Exercise
Fear
Medical conditions that can make sinus tachy appear?
Fever
Myocardial Ischemia
Hypovolemia (being dry)
Drugs that can cause sinus tachycardia?
Atropine
EPI
Dopamine
Caffeine
Main symptoms of sinus tachycardia
Dizzy
Hypotension later on
Angina due to heart muscles not having enough o2
What determine the sinus tachycardia treatment?
Should you treat symptoms of the underlying condition FIRST?
The underlying cause as with anything.
Treat condition first
Med classifications you can use for sinus tachycardia treatment
Beta blockers
Calcium channel blockers
Antipyretic
Analgesics
Examples of beta blockers for sinus tachy
Why do we use them for sinus tachy?
Metroprolol
Coreg
Labetolol
Reduce the HR and need for myocardial oxygenation
Example of a calcium channel blockers used for sinus tachycardia?
Why do we use it?
Verpamil
Slows the sa pacemaker down
Why use an antipyretic for sinus tachy and what is an example?
Use acetaminophen to reduce FEVER which is a big reason that HR can increase
Why use analgesics for sinus tachy?
To treat the pain which is causing HR to increase
You’re the nurse. You give beta blockers to one patient. You give calcium channel blockers to another patient. What do you need to monitor for both of these patients?
Monitor both BP and apical pulse
What is sick sinus syndrome?
Is it common?
Heart rhythm can be too fast, too slow, or a combination of both.
- Will have marked sinus bradycardia while sometimes having a coexisting atrial flutter or a fib. Can even have long pause and look like asystole
Very uncommon
Why is the patho behind sick sinus?
SA node doesn’t fire and the atria rapid fires not knowing what to do. Av node is no help either.
When patients have sick sinus syndrome what are symptoms like?
Can often come and go.
- may not have them at all
Your patient has fatigue, bradycardia, dizziness, SOB. Even co chest pains. They complain of palpitations. You check the rhythm and it shows a HR that is all over the place. Start, stop, etc. Then pt says they have a tickling feeling. What heart rhythm could this be?
Sick sinus syndrome
